Well, this marks a close to this year's Spring Experiment activities. We will begin again in the late summer this year with the Fire Weather and Heavy rain experiment starting August 24 and ending September 3. I would like to thank all of the participants this year from the various cooperative institutes and partners for coming and assisting in the product training and participating in the experiments alongside the forecasters. Without this participation, the experiment would not have been a success. I would also like to thank all the forecasters who participated this year and took valuable time away from their WFOs to come out and give us their time. The feedback gathered from the forecasters in the EFP and the EWP this year provided invaluable information to help improve the GOES-R products we evaluated this year. While not all feedback gathered this year may have been positive, it is important to remember that understanding the shortcomings in the demonstration strategy and the products themselves is essential to develop a robust product set prior to operational use once GOES-R launches. I would particularly like to thank Andy Dean, Gregg Grosshans, Israel Jirak and Chris Melick from the SPC's Science Support Branch for setting up and providing technical support for the NAWIPS systems on the EFP side. I would also like to thank Ben Baranowski and Darrel Kingfield from WDTB, as well as Kristin Kuhlman, Kevin Manross, Greg Stumpf and Travis Smith from NSSL for their assistance in setting up the AWIPS systems and providing technical support for the EWP side throughout the weeks. Without all of these people there would have been no experiment and I greatly appreciate all of their efforts. We are looking forward to continued interactions with the forecaster and product developer communities throughout the next year and into the coming years.
Thank you!
Friday, June 18, 2010
EWP weekly debrief
Today is the end of this year's Spring Experiment, and what a fitting end. Yesterday was our busiest day in the EWP over ND/MN/IA. As of the time of this entry there were 65 tornadoes reported over the area associated with the event. It was indeed a big day, and luckily there were no technical issues during the IOP. Unfortunately, due to the rapid developing nature of this event the GOES-R products were used only for a short time before it was essential to move into radar operations for warning purposes. The forecasters were inundated with issuing tornado warning pretty much in a consistent line from Canada down into IA. We were able to get some feedback and since this is the weekly debrief I was able to ask the forecasters in more detail, based on my observations this week as well as their survey responses. Here is a breakdown of what we discussed...
UWCI
I asked about the lead times from the surveys... 15-30 mins the general consensus?
"Hard to be sure because we were arriving at the HWT after convection was developing."
"Getting in there around noon would get more accurate results."
"The case event was already initiated when I got there."
"Struggling giving up screen space during severe weather" (from survey)... is there a display you think would help?
"Having an additional head would help. We were only provided with two screens so it changed our strategy."
"Would be useful for the mesoanalyst position at the WFO."
"4-panel devoted to those products works well."
I asked the forecasters if they were ok with more signals if that meant giving up some FAR...
"I would like earlier signals, like a probability signal... which part of my CWA is going to have the best chance... Some kind of signal before there's aggitated clouds would be helpful."
I asked the forecasters whether they preferred the CI or the cloud-top cooling...
"I used them both... kind of liked them both simultaneously."
"It was hard because it seemed it was 50/50 on detecting things so I lost a lot of confidence in using the product, but I did like the cloud-top cooling a little better because it seemed to do better."
I asked the forecasters if they preferred the accumulated of instantaneous fields...
"I stuck with the instantaneous for the most part, I don't think I even looked at the accumulated to be honest."
"I tended to look at the instantaneous."
Would you see a benefit in having a cloud-top cooling track?
"Yes... an overshooting top track would be very useful as well."
OTTC
Detections or magnitudes more useful?
"I looked at the detections only."
Did you see any correlations between OT detections and features developing on radar?
"Reflectivity was increasing above certain (height) levels at that time."
How often did the product correctly detect OTs that you could see on VIS/IR?
"Kinda 50/50."
"For a warning operator, I don't see this product adding much value to an on-going event..." (from survey) Why is that? Lack of detection, timeliness, applicability of product?
"Radar was more important... mix between timeliness and applicability."
"Get a good a western example case where you don't have radar."
"Maybe knock out some radars in a WES case."
PGLM
"It's an acquired taste, working with lightning data. I think it's a fundamental component in the decision making process trying to determine what's going on with the updraft... it's an interesting way of looking at it."
"With supercells I don't see any added benefit, unless it flared up right before an RFD developed... but I would have to see a lot of cases before I could determine that."
"Would be of a lot of value in low top events."
"Would be nice to see it in a non-supercell case event, like winter events."
"In terms of just lightning forecasting... I think the GLM stuff you were showing would be very useful in that area."
OVERALL / TRAINING
Overall feelings following the week...
"I'm 50/50... I'm not leaving here warm and fuzzy if that's what you're asking."
"When I came in I was very excited to have the convective initiation... I don't come out feeling as confident as I did and as excited as I did when I came in."
"The word convective initiation tool sounds awesome, maybe I went into it with high expectations as maybe seeing a tool with some probabilistic information."
How confident were you with the products following the training?
"The products were easy to understand so I was confident in using them."
What changes/additions would you like to see with the training?
Cases in the west re-iterated.
"The training itself was fine... it just seemed that it didn't perform as well as we would like to see."
I asked if the forecasters would like some sort of alert for the GOES-R products (UWCI, OTTC), so they would know when a detection was occurring, or if that would be more annoying than helpful...
"An initial alert would be nice... a continuous one would be overload."
"That would vary forecaster to forecaster."
Re-iterated the need for wind-based warning products.
"When I got really busy, I went back to the things I was used to using. I was just falling back on my normal routine."
"Would be nice on the first day to have a sort of hand-holding process to get used to the products."
"Maybe already have a base set of procedures so we don't have to spend 30 minutes setting everything up... especially on the first day."
Need cases where radar was out or nocturnal events over poor radar coverage.
UWCI
I asked about the lead times from the surveys... 15-30 mins the general consensus?
"Hard to be sure because we were arriving at the HWT after convection was developing."
"Getting in there around noon would get more accurate results."
"The case event was already initiated when I got there."
"Struggling giving up screen space during severe weather" (from survey)... is there a display you think would help?
"Having an additional head would help. We were only provided with two screens so it changed our strategy."
"Would be useful for the mesoanalyst position at the WFO."
"4-panel devoted to those products works well."
I asked the forecasters if they were ok with more signals if that meant giving up some FAR...
"I would like earlier signals, like a probability signal... which part of my CWA is going to have the best chance... Some kind of signal before there's aggitated clouds would be helpful."
I asked the forecasters whether they preferred the CI or the cloud-top cooling...
"I used them both... kind of liked them both simultaneously."
"It was hard because it seemed it was 50/50 on detecting things so I lost a lot of confidence in using the product, but I did like the cloud-top cooling a little better because it seemed to do better."
I asked the forecasters if they preferred the accumulated of instantaneous fields...
"I stuck with the instantaneous for the most part, I don't think I even looked at the accumulated to be honest."
"I tended to look at the instantaneous."
Would you see a benefit in having a cloud-top cooling track?
"Yes... an overshooting top track would be very useful as well."
OTTC
Detections or magnitudes more useful?
"I looked at the detections only."
Did you see any correlations between OT detections and features developing on radar?
"Reflectivity was increasing above certain (height) levels at that time."
How often did the product correctly detect OTs that you could see on VIS/IR?
"Kinda 50/50."
"For a warning operator, I don't see this product adding much value to an on-going event..." (from survey) Why is that? Lack of detection, timeliness, applicability of product?
"Radar was more important... mix between timeliness and applicability."
"Get a good a western example case where you don't have radar."
"Maybe knock out some radars in a WES case."
PGLM
"It's an acquired taste, working with lightning data. I think it's a fundamental component in the decision making process trying to determine what's going on with the updraft... it's an interesting way of looking at it."
"With supercells I don't see any added benefit, unless it flared up right before an RFD developed... but I would have to see a lot of cases before I could determine that."
"Would be of a lot of value in low top events."
"Would be nice to see it in a non-supercell case event, like winter events."
"In terms of just lightning forecasting... I think the GLM stuff you were showing would be very useful in that area."
OVERALL / TRAINING
Overall feelings following the week...
"I'm 50/50... I'm not leaving here warm and fuzzy if that's what you're asking."
"When I came in I was very excited to have the convective initiation... I don't come out feeling as confident as I did and as excited as I did when I came in."
"The word convective initiation tool sounds awesome, maybe I went into it with high expectations as maybe seeing a tool with some probabilistic information."
How confident were you with the products following the training?
"The products were easy to understand so I was confident in using them."
What changes/additions would you like to see with the training?
Cases in the west re-iterated.
"The training itself was fine... it just seemed that it didn't perform as well as we would like to see."
I asked if the forecasters would like some sort of alert for the GOES-R products (UWCI, OTTC), so they would know when a detection was occurring, or if that would be more annoying than helpful...
"An initial alert would be nice... a continuous one would be overload."
"That would vary forecaster to forecaster."
Re-iterated the need for wind-based warning products.
"When I got really busy, I went back to the things I was used to using. I was just falling back on my normal routine."
"Would be nice on the first day to have a sort of hand-holding process to get used to the products."
"Maybe already have a base set of procedures so we don't have to spend 30 minutes setting everything up... especially on the first day."
Need cases where radar was out or nocturnal events over poor radar coverage.
Review of yesterday's event... an EWP perspective
24-hour UWCI nowcasts (top left), overshooting top (top right) and thermal couplet detections (bottom left), and SPC storm reports (bottom right) for 17 June 2010.
Today we discussed yesterday's event over ND/MN/IA and I wanted to mention a few things we discussed with the forecasters regarding the performance of the UWCI and OTTC products leading up to and during the event. We showed the forecasters the 24-hour accumulations of UWCI, cloud-top cooling, overshooting top and thermal couplet detections with regards to severe reports from the SPC (see images above), as well as their own experiences. Forecasters did notice that cloud-top cooling was occurring on southern edge, but it was already ongoing on radar. The first UWCI signals were seen at 1855 UTC with the convection that was developing over ND and MN. The first overshooting top was detected at 1915 UTC over northern MN. These occurred just prior to beginning operations in the HWT, so it is hard to determine the CI lead times for this event given that we did not see the first detections of CI. I reiterated that we are hoping to expand the experiment in the future years by having overlapping shifts that would provide additional time to evaluate GOES-R Proving Ground products in a nowcasting perspective, which is what they are meant for originally. Forecasters did not see any thermal couplets in real-time, but did notice a few overshooting tops, especially when they began. However, they mentioned that the storms seem more low topped in nature and this may have hindered the products ability to detect these features. They were honest with me in saying that as soon as they moved into warning operations they turned the GOES-R stuff off because they did not feel it provided them with additional warning information and needed the window space for their traditional radar products.
Jordan Gerth did show the forecasters an AVHRR image that demonstrated similar to what GOES-R would see regarding overshooting tops and thermal couplets and noted that the detection efficiency would be much better. The forecasters were impressed with this and agreed that the products would perform much better in the future and appreciated us showing them the products now. The forecasters also did note that in the case of a line forming upstream from main convective area, convective initiation being detected in the line behind would help prevent getting tunnel vision and increase their situational awareness.
Thursday, June 17, 2010
SATCAST improvements identified
SATCAST CI nowcast overlaid on visible satellite imagery for 1945 (top left), 2002 (top right), 2015 (mid left), 2033 (mid right), and 2045 UTC (bottom center) on 17 June 2010.
Today we were able to remedy the issues we were having with the SATCAST product within our NAWIPS system. While examining today's potential severe weather outbreak over ND/MN/IA I noticed a few issues that have been relayed to the developers for future improvements. The product did not detect development over southwestern MN where some obvious convective initiation occurred between 1945 and 2045 UTC (see images above). We examined the cloud object detections provided within the output (see images below) and noticed that this area was not widely flagged as having any cloud objects within it. I discussed this with the developers and it was determined that because the clouds were developing so rapidly, the 15-minute cloud typing product used by SATCAST produced cloud types that changed so rapidly that the SATCAST algorithm's quality control threw them out. It should be noted that GOES-13 was operating in RSO during the course of the day, but due to limited computing resources it is not possible to run the product outside of the 15 minute CONUS scans at the moment. It is theorized that this issue would not exist given that the product was able to utilize RSO scans. This does help highlight a major benefit of utilizing higher temporal resolution data that will be available continuously when GOES-R is operational.
SATCAST CI nowcasts (red) and detected objects (blue) for 1945 (top left), 2002 (top right), 2015 (bottom left) and 2045 UTC (bottom right) on 17 June 2010. Note that the 2033 UTC image was not generated and the 2045 UTC image has no objects or CI nowcasts.
It also seemed as though the product was not producing output for the 2032 and 2045 UTC time periods (see images above). I also mentioned this to the developers and they discovered that the algorithm could not handle the scanning schedule changes that occurred with GOES-13 RSO. The algorithm has been changed to accommodate the scan schedule and the output has resumed.
EWP daily briefing... 6/17/2010
At the beginning of the briefing we discussed yesterday real-time IOP event over the Sterling, VA WFO CWA. We had the ability to use the PGLM output from the DCLMA for this event. Most of the warnings issued were for severe wind threats and were fairly marginal. One of the forecasters mentioned that he focused on the PGLM products because of the marginal nature of the event to try and pick out regions of greater importance since the radar and MRMS products were showing similar features for most of the convection around the area. However, due to the marginal nature of the event, no strong conclusions were drawn as to the usefulness of a lot of the experimental data. One of the forecasters brought up the idea of creating regional versions of some of the products to try and draw more information from them. This may eventually be useful for products like the CI and cloud-top cooling products since we have seen some regional dependence on the product performance (ie - diagnostic over SE US)
We also discussed the performance of the UWCI over the same area. The forecasters reiterated the lack of detection over WV/VA border from yesterday's blog post. We believe that this was due to some microphysical issues being presented in the cloud typing product that were masking out the CI signals. We mentioned that we had wished we had moved to SD sooner, which is where we ended up for the remainder of yesterday's IOP. There were a lot of signals over that area (see image above), but we were unsure as to the timing of them since we were not watching in real time. This would be a good case to look at in the future. Also, notice the lack of signals over the Sterling and State College WFO areas where we focused at the beginning of the day. Jordan Gerth discussed with the forecasters about the idea of providing a cloud-top cooling rate 'image' with no filtering, which would allow for the forecasters to see all areas of cooling/warming regardless of cloud motion or other effects that are currently removed. This would allow the forecasters decide for themselves what are false signals and may be particularly useful for determining the life cycle of MCS's and weakening supercell storms.
24-hour overshooting top (left) and thermal couplet (right) detections for 16 June 2010.
We examined the overshooting top and thermal couplet detections (see images above) and saw that both the overshooting top and thermal couplet detections did correlate well to the location of the severe weather in this case, especially over SD. However, when these were seen during the real-time IOP, it was already obvious that severe weather was occurring based on reports being received and the standard radar data. The overshooting top detections that continue further east, as well as the blob of CI nowcasts east of the tornadic storm were questioned by the forecasters since they occurred after the IOP ended and they were not sure how legitimate they were. We did look back very quickly to see what happened and it seemed as though a MCS developed later on associated with many additional warnings and it would have been nice to see the performance of the products in that instance. Again, this would be a good case to look at in the future. We will attempt to archive the data, but it may be difficult since we do not yet have dedicated disk space to do so.
The plan for today is to operate over MN and IA. This is our last chance for real-time IOPs and it looks like it should be a good one for GOES-R with the lack of cirrus in the area... assuming we get started soon enough.
Hail Probability Product from 16 June
The image above shows the severe hail probability product from 16 June, valid from 21-00Z. Also plotted are the severe weather reports between 18-00Z; hail is denoted by 'a'. Only a couple of the reports in Montana occurred prior to 21Z, the rest being observed within the hail product's 3-hour time window. For reference, the 2115 UTC GOES-East IR image is below. The product did a nice job of highlighting the regions in which hail was observed (and other severe weather in the case of eastern Kansas). In particular, note the small region near Sydney, Nebraska. There, towering cumulus had just begun to form and a bullseye of probabilities can be seen. Hail was reported there around 2200 UTC.
Use of Simulated WRF Imagery in the EFP
As part of the morning EFP session, we took a look back at yesterday's severe weather forecast. The domain was centered over State College, PA. Many of the model guidance products pointed toward Pennsylvania as a region for possible severe weather. However, as can be seen in the visible GOES-East image above (right), low clouds were present across the eastern part of the state, and the 15Z analyzed SBCAPE showed positive values only where solar insolation had occurred. The image on the left shows the simulated 10.35 micron band (from the NSSL WRF-ARW) also at 15Z, along with the model's SBCAPE field. Note that the model correctly places the low clouds in eastern Pennsylvania, but has CAPE values a bit too high in western PA.
The images above show the same fields, except valid at 22Z. Some convection had begun to fire in the unstable region in central PA, and the model also showed convection in this area. In this case, the WRF seemed to perform quite well with the evolution of afternoon convection. However, its overprediction of the instability lead to the model storms being a bit too strong. No severe weather reports came out of Pennsylvania.
EFP simulated satellite evaluation
Today in the EFP's QPF group Dan Lindsey led a discussion on the comparison of the simulated satellite imagery from the NSSL-WRF to that which was observed over the past few hours (see image above). They used this simulated satellite imagery to determine the accuracy of the current 00Z NSSL-WRF model run for the day. It was determined that is is missing some convective development down near NE and IA, but that the main threat area up near MN is being captured fairly well. This provides them with confidence that the model should handle the rest of the day's development fairly well.
Wednesday, June 16, 2010
EWP real-time IOP CI feedback
Today's IOP focused over the DCLMA domain to get some real-time PGLM experience. The forecasters broke up into two groups and localized over the Sterling, VA and State College, PA WFOs. The Sterling WFO group have been issuing severe thunderstorm warnings based on PGLM and MRMS products over the past couple hours. I was sitting with the State College WFO group as they were focusing on the UWCI products, watching for convective initiation over their area. One of the forecasters had multiple GOES-R Proving Ground products (UWCI, cloud-top cooling, overshooting top, and thermal couplet) into a 4-panel display and mentioned to me that this display strategy would be extremely useful as a situational awareness tool for monitoring satellite convective information.
GOES-13 IR imagery for 1832 (top left), 1845 (top right), 1902 (bottom left) and 1915 UTC (bottom right) on 16 June 2010. Area of interest noted by green circle.
We noticed an area of obvious convective development that was not detected by the UWCI product on the WV/VA border at 1915 UTC and the forecaster asked me to explain why no CI nowcast was made. Looking at the IR, you could see significant cooling occurring from 1832 and 1915 UTC (see above), but still no signals were seen. Jordan Gerth and I looked at the cloud typing output to see if we could draw any conclusions from that to determine what was going on (see below). Most of the area was covered by cloud types identified as 'water' or 'mixed phase'. However, there were a few spots of 'cirrus' classification over WV nearby where the CI nowcast should have been made. It seemed on visible and IR satellite that this may not have been the case, but this is hard to determine for sure. Jordan suggested that because there were these spots nearby that they may have been contaminating the spatial tests required by the algorithm to flag an area as filtered cloud-top cooling, and thus not allow for a CI nowcast to be made. This may be a fluke case where nothing can be done, but it may be useful to examine this in more detail to see if something can be improved.
UW-CIMSS Cloud typing product for 1832 (top left), 1845 (top right), 1902 (bottom left), and 1915 UTC (bottom right) on 16 June 2010. Area of interest noted by red circle.
GOES-13 IR imagery for 1832 (top left), 1845 (top right), 1902 (bottom left) and 1915 UTC (bottom right) on 16 June 2010. Area of interest noted by green circle.
We noticed an area of obvious convective development that was not detected by the UWCI product on the WV/VA border at 1915 UTC and the forecaster asked me to explain why no CI nowcast was made. Looking at the IR, you could see significant cooling occurring from 1832 and 1915 UTC (see above), but still no signals were seen. Jordan Gerth and I looked at the cloud typing output to see if we could draw any conclusions from that to determine what was going on (see below). Most of the area was covered by cloud types identified as 'water' or 'mixed phase'. However, there were a few spots of 'cirrus' classification over WV nearby where the CI nowcast should have been made. It seemed on visible and IR satellite that this may not have been the case, but this is hard to determine for sure. Jordan suggested that because there were these spots nearby that they may have been contaminating the spatial tests required by the algorithm to flag an area as filtered cloud-top cooling, and thus not allow for a CI nowcast to be made. This may be a fluke case where nothing can be done, but it may be useful to examine this in more detail to see if something can be improved.
UW-CIMSS Cloud typing product for 1832 (top left), 1845 (top right), 1902 (bottom left), and 1915 UTC (bottom right) on 16 June 2010. Area of interest noted by red circle.
Results from Tuesday's EFP forecast
Following up Tuesday's post on the use of simulated imagery, the low cloud deck turned out to be quite important for the storm evolution. Above is the observed GOES-East visible image from 1845UTC. The stratus deck had burned off between 15-18 UTC, and a cumulus cloud/no-cloud boundary was clearly evident in the visible image across southern Indiana and central Illinois. This boundary presumably resulted from the differential heating resulting from the morning clouds. Also note the storm which had formed on the boundary in eastern Illinois, and the multiple storms in southeast Missouri. These progressed to the east-northeast and subsequently grew upscale into a bowing MCS. The severe reports are below.
The blue dots represent severe wind reports. It's interesting that the northern boundary of the wind reports across central Illinois and Indiana corresponds quite well with the cumulus cloud boundary noted above. Most of the high-res models, including the NSSL WRF (for which we looked at the simulated imagery yesterday) had a bowing MCS further north. It turned out that the low clouds limited the instability further north, and the severe weather was confined to the south where more heating had occurred. This was a nice example of how the simulated imagery might be used to diagnose the model's treatment of morning clouds.
The blue dots represent severe wind reports. It's interesting that the northern boundary of the wind reports across central Illinois and Indiana corresponds quite well with the cumulus cloud boundary noted above. Most of the high-res models, including the NSSL WRF (for which we looked at the simulated imagery yesterday) had a bowing MCS further north. It turned out that the low clouds limited the instability further north, and the severe weather was confined to the south where more heating had occurred. This was a nice example of how the simulated imagery might be used to diagnose the model's treatment of morning clouds.Tuesday, June 15, 2010
EWP daily briefing... 6/15/2010
During today's EWP briefing we discussed the previous day's flooding event over OKC from a PGLM perspective. Unfortunately the event unfolded in the morning hours when the EWP was not operating, so we were unable to view the data in real-time. Kristin Kuhlman presented the archived data and discussed with the forecasters what the PGLM showed during the event. She also overlaid the OKLMA flash contours to show how the PGLM relates to what was actually occurring (see above), which really helped the forecasters get a grasp over what the PGLM was showing them. They noted that the lightning seemed to be mainly focused with convection developing on the backside of the system and that this would help radar operators focus on which areas had continued development and represented an increased threat for flooding and severe weather in the future.
24-hour UWCI detections (top left), overshooting top detections (top right), thermal couplet dtetections (bottom left), and SPC severe reports (bottom right) from 14 June 2010
Jordan Gerth showed the UWCI and OTTC products over the past 24 hours in comparison to the severe reports from the same time period (see above). He pointed out the the UWCI had a lot of hits over the southeast with the diurnal convection that was not necessarily severe. He was unsure about how the UWCI performed with the the widespread swatch of wind reports through NC, but it is highly possible that the mass of UWCI signals in WV may be in initiation point for this convection... but we would need to do an in depth analysis of the event to determine this. Also, the numerous severe reports over southern IN seemed to have no UWCI detections associated with them. We suspected this was due to the presence of cirrus over the area. Jordan also noted the high density of overshooting top detections over OK with very few severe reports. He made sure to mention that the overshooting top detections are not necessarily associated with severe weather at the surface, as they are more of an indication of turbulence and lightning threats. There were only a few thermal couplet detections, which are highly linked to severe weather. The three located over TX seemed to be the best examples for this day. Jordan also did a quick introduction to the UW-CIMSS Nearcasting product for the EWP forecasters and showed a couple case examples in addition to the output for today to show areas of convective destabilizations associated with differential theta-e and precipitable water fields. Unfortunately we were unable to establish data flow for this product in time for this Spring Experiment, but we do plan on having it for future experiments.
The plan for the day is to once again start early and operate over the SPC moderate risk area in southern IL/IN to examine the GOES-R Proving Ground products prior to warning operations. With a relatively cirrus free sky, it should be a good event to demonstrate the UWCI. However, some storms are currently ongoing and are possibly severe, so we are hoping for some new development further south and west of the ongoing convection. The WFO's localized for the start of the IOP will be Indianapolis, IN and Louisville, KY.
Simulated satellite imagery in the EFP
On Tuesday morning, the Ohio valley region has been chosen for the daily forecast. The left image above is the 4-km NSSL WRF-ARW simulated 10.35 micron channel valid at 15 Z, and the image on the right is the observed GOES-East image from 1515 UTC. One of the biggest advantages of the GOES-R simulated imagery is the ability to evaluate the model's representation of morning clouds. In this case, the model appears to have a pretty good handle on the cold cloud placement. A more subtle but relevant feature is the low clouds across central and northern Indiana. These clouds may inhibit heating and limit the destabilization. At 15 UTC, the model has burned off the low cloud layer across central Indiana, but the observations show that the cloud deck is still present.
The image above shows the simulated band 13 image valid at 18 UTC. Note that the model has formed a new storm in southern Illinois which is moving into the area in question in Indiana. It will be interesting to see whether such a storm forms, and how it evolves as it moves into Indiana.
Hail Probability Product
Data from yesterday's probability of severe hail product was examined. The image above shows the probability forecast (%) from 20 UTC, valid from 20-23 UTC. Also plotted are the severe reports, where hail reports are denoted by 'a'. NAWIPS requires all reports from 18-00 UTC to be plotted at the same time, so not all of the reports above occurred during the 20-23 UTC forecast period. Specifically, the 3 southernmost reports occurred after 23 UTC.
Cold cloud tops from GOES-East dominated the input parameters, but the instability from the SPC mesoanalysis and the RUC forecast contributed. Note that the majority of the hail reports fell within the 1% contour in west Texas, although not specifically within the maximum probability area. The second max across Oklahoma saw no reports; this is a weakness of the product....if cold cloud tops are observed over regions of moderate instability, as was in the case in Oklahoma, higher probabilities will result. I looked at earlier forecasts, and on this particular day the product did not provide a significant lead-time prior to the development of storms.
Monday, June 14, 2010
Real-time PGLM operations
The forecasters are now engaged in a real-time IOP over Norman, OK and Lubbock, TX. Luckily the OKLMA became operational once again right before the dinner break so we are able to get the forecasters familiar with the PGLM product. The first two forecasters to look at the PGLM data had some interesting comments regarding the product's potential uses and performance. One of the forecasters mentioned how useful the product would be in the case of being overloaded with radar information. For instance, during weak cap, high instability days when storms cover the entire radar area a radar operator can get 'tunnel vision' on a couple storms they initially think are the most important and forget about the rest. She said that a GLM product would be very useful in getting you 'back to reality' when you get overwhelmed and help you identify the cells which are most important at that time. Also, the same forecaster mentioned how they would use this in situations when they are bordering on issuing a severe warning. When the radar information is ambiguous or unchanging, the GLM would help determine whether or not to issue the warning based on any dramatic increases seen in the number of total flashes in the cell.
In one case during the IOP we saw the first occurrence of flashes from the PGLM occurring with a growing cell near the center of the OKLMA network 40 minutes prior to the first CG. Flash rates reaching 25 flashes / 8 km / min occurred 25 minutes prior to the first CG for the same cell. She mentioned that this would be extremely helpful in determining whether the cell was actually a 'thunderstorm' and something to watch out for, stating that a lot of forecasters use the first occurrence of a CG to start thinking about the possibility of that cell ever becoming severe. This would provide a much heightened level of situational awareness, especially when storms can rapidly produce tornadoes, severe hail and/or winds with little warning.
In one case during the IOP we saw the first occurrence of flashes from the PGLM occurring with a growing cell near the center of the OKLMA network 40 minutes prior to the first CG. Flash rates reaching 25 flashes / 8 km / min occurred 25 minutes prior to the first CG for the same cell. She mentioned that this would be extremely helpful in determining whether the cell was actually a 'thunderstorm' and something to watch out for, stating that a lot of forecasters use the first occurrence of a CG to start thinking about the possibility of that cell ever becoming severe. This would provide a much heightened level of situational awareness, especially when storms can rapidly produce tornadoes, severe hail and/or winds with little warning.
EWP daily plan
Following the training sessions for the GOES-R UWCI, OTTC and PGLM products we had planned to move into an immediate IOP focusing over the Norman, OK WFO to get some exposure for the PGLM product with the chance of severe weather entering the area. Unfortunately as we were finishing the training we had heard that some of the OKLMA stations went down due to the heavy flooding occurring in central OK. Therefore, we decided that the current plan should be to move the domain towards the VORTEX-II domain south of Lubbock, TX following the MRMS training for some severe weather applications for the remainder of the evening.
Missing data... now partially restored
Sometime last week, changes were made to the experiment's NAWIPS systems and the GOES-R Proving Ground Products SATCAST and Probability of Severe Hail were removed by an unknown party. I worked with the SPC IT staff to reincorporate the missing data into the NAWIPS systems... The Probability of Severe Hail is back up, but we are still trying to get SATCAST back up and running. The simulated satellite imagery, lightning threat, UWCI and OTTC products remained unharmed. Will keep an eye on this and work on getting the SATCAST back up and running.
The final week begins...
Today marks the start of the final week of the Spring Experiment (it's gone by so fast). This week we will once again be participating in both programs, which means back to the 14 hour days. Our visitors this week include Jim Gurka and Bonnie Reed from the GOES-R Program Office, Dan Lindsey from CIRA and Jordan Gerth from UW-CIMSS. Jordan will be our resident expert within the EWP because he is directly tied to the UWCI and OTTC products, so he will be providing the training and expertise during real-time IOPs.
This morning begins with around the room introductions and an overview of the project...
This morning begins with around the room introductions and an overview of the project...
Friday, June 11, 2010
EWP weekly debrief
Here is the breakdown from this week's EWP weekly debrief...
UWCI
This week was plagued by cirrus... can't remove it so we need to communicate well the limitations of the product. Forecasters were mentioning that they were constantly referring to the cloud type web page and suggested providing this into AWIPS. Will severely limit the applicability.
"If it's a good day to use it, the forecasters will use it... Most useful prior to development... right now things have to start developing before we issue products, this gives us some additional lead time."
Forecasters mentioned that the product would be useful in nighttime operations... possibly get more lead time... At night, stuff fires so quickly... perhaps providing a CI alarm in AWIPS would help situational awareness. Forecasters suggested providing a nighttime WES case for training. Lee is going to distribute web site and explain how to use it so they can look at it anytime.
Expressed interest in CI accumulated to follow CI signals through time in case they missed a scan.
Limitations in sensor scan time noted.
Forecasters mentioned the interest in providing more signals. they saw a lot of cases where CI was obvious but was not captured by the product. I asked if they were ok with the idea to sacrifice FAR for more detections...
"More times I expected to see something and didn't happened more often than not... not useful if things aren't showing where I expected to see it."
"Could you build different thresholds? Could you build one that was not so strict?"
"What about probabilistic detection? Then you can set your own threshold."
"Concerned about FAR getting too high because then it'll stop getting used."
There was a request for using additional bands... "You guys know the best bands to use... If you can get more information from other bands, go for it"
I asked if they saw the UWCI product being a precursor to lightning...
"Did not specifically check."
"I was more correlating the 35-40 dBZ"
During an event with a strong cap, the UWCI/CTC showed signals but no development occurred (or continued to occur)... perhaps provide a case of this in training.
From yesterday's IOP over Boulder, CO area... cell showed CI at 22:30 UTC... at 22:58 UTC a 30-40 dBZ occurred... showing 28 min lead time. Similar results were seen throughout the week.
A forecaster asked is testing on simulated satellite imagery planned? Yes, but currently the computation time is expensive so 5 min data would be rough.
Forecaster requested that it would be nice if the UWCI automatically loaded with satellite imagery in AWIPS.
OTTC
Forecasters mentioned they don't know what overshooting tops tell you... need more examples of this in training/literature.
Losing confidence by high threshold when you can see in visible... maybe a training issue... when you see a detection maybe it's more serious than a typical OT.
Combining with storm top divergence... "I think there's a lot of potential there."
Forecasters requested thermal couplet/overshoot detections in one product... hard to watch two different products... takes up a window in their D2D... "The more we can combine the better."
PGLM
Need to understand the importance of lightning "jumps"... show what would be significant... "What type of airmass dependence would we see with that?"
Need a rate of change product. Also, need to explain downward jumps... "What do we think is going on with the storm?"
Polarity information... needs to be mentioned that the ground based can be used in comparison.
Smoothing reducing peaks and faking a high res product.
Max-value track product would be useful... similar to rotation/hail track MRMS products.
"I think one of the problems with using lightning data in the WFO (currently) is that forecasters realize that it's (NLDN) such a small percentage of what's really going on."
"My guess is when the product becomes available it'll become a mainstream product that people are looking at all the time."
"Not necessarily going to be the main warning product, but it will be a good confirmation tool. If I had paid more attention and been more aware I could have issued my tornado warning one scan earlier." (24 May 2008 case event)
I asked if they noticed any lead time on CG from the PGLM... ~10 mins in general... canned case and real-time.
OVERALL/TRAINING
Training experience...
"Getting some simulations where the product does work out to field (WES cases) is important... hard to trust people with a Powerpoint. But be careful of putting out WES cases... 20 min articulate cases are fabulous... too long and we don't have time."
"Thankful for the canned case"
Asked forecasters how confident in the products they were after the training...
"With the UWCI I felt really good about, the other one (OTTC) was good too, I just probably don't experience it as much in operations"
"If you guys see something during real-time operations, don't hesitate to tell us something was there... don't hesitate to be the hands on instructor for the first couple days."
I asked what additional information they would like to see in the training...
"When you see a detection, provide a 'here's what it means' quicklook that we can refer to in operations."
Examples where it didn't work (cirrus, cap), and why are needed.
GOES-R products seem to be more useful before storm initiation.
Forecasters re-iterated need for object tracking and end to end multi-sensor tool... combine lightning, radar and satellite.
MRMS and GOES-R products are sparse grids... what could be done to improve your awareness that things are happening?
"Message or prompt to tell you when things are occurring."
"Some hesitation in alarms though... start to drown them out, especially when too many things trying to alert you."
"Number in lop left corner showing number of detections, like NLDN products, would be very useful."
"If there are a lot of false detections this would be hard."
Forecasters mentioned that you shouldn't be too worried about shipping the color curve information... forecasters are going to change it anyways.
"Glad you guys are here... good to have the interactions that we have and learn how these things work."
UWCI
This week was plagued by cirrus... can't remove it so we need to communicate well the limitations of the product. Forecasters were mentioning that they were constantly referring to the cloud type web page and suggested providing this into AWIPS. Will severely limit the applicability.
"If it's a good day to use it, the forecasters will use it... Most useful prior to development... right now things have to start developing before we issue products, this gives us some additional lead time."
Forecasters mentioned that the product would be useful in nighttime operations... possibly get more lead time... At night, stuff fires so quickly... perhaps providing a CI alarm in AWIPS would help situational awareness. Forecasters suggested providing a nighttime WES case for training. Lee is going to distribute web site and explain how to use it so they can look at it anytime.
Expressed interest in CI accumulated to follow CI signals through time in case they missed a scan.
Limitations in sensor scan time noted.
Forecasters mentioned the interest in providing more signals. they saw a lot of cases where CI was obvious but was not captured by the product. I asked if they were ok with the idea to sacrifice FAR for more detections...
"More times I expected to see something and didn't happened more often than not... not useful if things aren't showing where I expected to see it."
"Could you build different thresholds? Could you build one that was not so strict?"
"What about probabilistic detection? Then you can set your own threshold."
"Concerned about FAR getting too high because then it'll stop getting used."
There was a request for using additional bands... "You guys know the best bands to use... If you can get more information from other bands, go for it"
I asked if they saw the UWCI product being a precursor to lightning...
"Did not specifically check."
"I was more correlating the 35-40 dBZ"
During an event with a strong cap, the UWCI/CTC showed signals but no development occurred (or continued to occur)... perhaps provide a case of this in training.
From yesterday's IOP over Boulder, CO area... cell showed CI at 22:30 UTC... at 22:58 UTC a 30-40 dBZ occurred... showing 28 min lead time. Similar results were seen throughout the week.
A forecaster asked is testing on simulated satellite imagery planned? Yes, but currently the computation time is expensive so 5 min data would be rough.
Forecaster requested that it would be nice if the UWCI automatically loaded with satellite imagery in AWIPS.
OTTC
Forecasters mentioned they don't know what overshooting tops tell you... need more examples of this in training/literature.
Losing confidence by high threshold when you can see in visible... maybe a training issue... when you see a detection maybe it's more serious than a typical OT.
Combining with storm top divergence... "I think there's a lot of potential there."
Forecasters requested thermal couplet/overshoot detections in one product... hard to watch two different products... takes up a window in their D2D... "The more we can combine the better."
PGLM
Need to understand the importance of lightning "jumps"... show what would be significant... "What type of airmass dependence would we see with that?"
Need a rate of change product. Also, need to explain downward jumps... "What do we think is going on with the storm?"
Polarity information... needs to be mentioned that the ground based can be used in comparison.
Smoothing reducing peaks and faking a high res product.
Max-value track product would be useful... similar to rotation/hail track MRMS products.
"I think one of the problems with using lightning data in the WFO (currently) is that forecasters realize that it's (NLDN) such a small percentage of what's really going on."
"My guess is when the product becomes available it'll become a mainstream product that people are looking at all the time."
"Not necessarily going to be the main warning product, but it will be a good confirmation tool. If I had paid more attention and been more aware I could have issued my tornado warning one scan earlier." (24 May 2008 case event)
I asked if they noticed any lead time on CG from the PGLM... ~10 mins in general... canned case and real-time.
OVERALL/TRAINING
Training experience...
"Getting some simulations where the product does work out to field (WES cases) is important... hard to trust people with a Powerpoint. But be careful of putting out WES cases... 20 min articulate cases are fabulous... too long and we don't have time."
"Thankful for the canned case"
Asked forecasters how confident in the products they were after the training...
"With the UWCI I felt really good about, the other one (OTTC) was good too, I just probably don't experience it as much in operations"
"If you guys see something during real-time operations, don't hesitate to tell us something was there... don't hesitate to be the hands on instructor for the first couple days."
I asked what additional information they would like to see in the training...
"When you see a detection, provide a 'here's what it means' quicklook that we can refer to in operations."
Examples where it didn't work (cirrus, cap), and why are needed.
GOES-R products seem to be more useful before storm initiation.
Forecasters re-iterated need for object tracking and end to end multi-sensor tool... combine lightning, radar and satellite.
MRMS and GOES-R products are sparse grids... what could be done to improve your awareness that things are happening?
"Message or prompt to tell you when things are occurring."
"Some hesitation in alarms though... start to drown them out, especially when too many things trying to alert you."
"Number in lop left corner showing number of detections, like NLDN products, would be very useful."
"If there are a lot of false detections this would be hard."
Forecasters mentioned that you shouldn't be too worried about shipping the color curve information... forecasters are going to change it anyways.
"Glad you guys are here... good to have the interactions that we have and learn how these things work."
PGLM: Week in Review
I would like to offer my thanks to all of the forecasters who participated this week with the pseudo-GLM and other products this week. It was an educational experience for myself too, as I was provided with great suggestions for improved training and developing additional products to improve integration of future GLM data.
There were two big items I can take away from my participation this week. First, the PGLM is a strong support tool for the forecasters that helps provide confidence to the forecaster's thoughts on the current event. This matches what I have seen in previous assessments of total lightning data with NASA SPoRT's partners. Based on what was seen this week, one forecaster commented that the GLM data may eventually be a mainstream product with forecasters to provide situational awareness. Second, the utility of total lightning data will be greatly enhanced with some form of flash rate of change product. Currently, a lightning jump is a subjective analysis and there is a desire to create a more quantitative product. The first step is likely a maximum flash density "track" product that does not require a cell tracking algorithm. Ultimately, the work done by University of Alabama in Huntsville researchers to develop a lightning jump algorithm could be the best way to give forecasters valuable data in a form that does not overwhelm them during severe weather operations.
There were two big items I can take away from my participation this week. First, the PGLM is a strong support tool for the forecasters that helps provide confidence to the forecaster's thoughts on the current event. This matches what I have seen in previous assessments of total lightning data with NASA SPoRT's partners. Based on what was seen this week, one forecaster commented that the GLM data may eventually be a mainstream product with forecasters to provide situational awareness. Second, the utility of total lightning data will be greatly enhanced with some form of flash rate of change product. Currently, a lightning jump is a subjective analysis and there is a desire to create a more quantitative product. The first step is likely a maximum flash density "track" product that does not require a cell tracking algorithm. Ultimately, the work done by University of Alabama in Huntsville researchers to develop a lightning jump algorithm could be the best way to give forecasters valuable data in a form that does not overwhelm them during severe weather operations.
Thursday, June 10, 2010
Early UWCI detection leads to golf-ball sized hail producing storm
At 2132 UTC UWCI made a detection of a 'Pre-CI Growth' with a convective element located withing the very southern region of the Boulder, CO CWA (See figure above). At approximately 2204 UTC, radar imagery indicated the first echo > 35 dBZ with this flagged convection giving the UWCI 32 minutes of lead time on the significant radar echo. At approximately 2309 UTC the ensuing storm had spotter reports of golf ball sized hail. A success!
Additionally, as a side note, UWCI has be performing well most of the afternoon, since our four-letter friends cirrus have not been creating problems for the algorithm. A lot of the early convection that has been flagged did not amount to much, since it would die as it hit the very large cap in place, thanks to ~ 19C temperature layer at 850 mb. Radar echoes would reach 40-45 dBZ to about 4000 ft and then die. Lead times on these initial convective elements were approximately 20-30 minutes. Later indications of cloud top cooling are showing more progress with vertical development.
Simulated lightning threat over western US for fire weather applications
Today I spoke with Mark Burger from NWS Eureka, CA who is participating in the EFP this week about the GOES-R products and our future plans for a fire weather and heavy rain experiment. One of his questions regarding the NSSL-WRF simulated lightning threat product particularly peaked my interest. He asked how the lightning threat performs over the west where it would be very useful in fire weather forecasting operations. I pulled up the output from yesterday's 00Z run and overlaid NLDN lightning detections over the OR/WA/ID area for some convection that occurred in the late afternoon. The attached image in this post shows an example of this output for the 2100 UTC time period (a 21-hour forecast), with NLDN lightning detections over the past hour shown as red + or - symbols. The lightning threat product, which predicts total lightning over each square km per 5 mins at the same time captured well the regions of peak lightning interest. This will be a very interesting thing to examine during this year's fire weather / heavy rain experiment taking place this August/September. I passed along the web link for this output, as well as some other GOES-R products, for him to use in the office and distribute amongst other forecasters.
Real-time PGLM: 9 June 2010
After a quiet first two days during our operation times, we had the chance to do real-time operations for the pseudo-GLM over the north Alabama domain Wednesday. The SPC outlook had a slight risk over the Memphis and Nashville, TN as well as Huntsville, AL county warning areas covering the northern half of our domain. Wind was the predominant threat, but severe hail was a possibility. Forecasters started in the Memphis county warning area to get a feel for the PGLM product in the far western part of the domain and then transferred to Nashville and Huntsville later in the evening. Overall, few warnings were issued, but this was a good event to introduce forecasters to the PGLM in real-time.
I will add a few general comments and then include two images from the event. Overall, like the 24 May 2008 archived case, the impression was that the PGLM served as a good situational awareness tool. I then asked about the resolution of the product. Again, the response is that forecasters always want better resolution. In this case, though, the PGLM was adequate for what it was being used to analyze. One comment was that the PGLM was useful to see the convective cores, particularly during initiation. The NLDN has been used in this role, but the PGLM can give a few extra minutes lead time on initiation since most storms initiate with intra-cloud lightning before cloud-to-ground strikes. Another interesting comment after the event was that the PGLM could be very useful for coastal WFOs where the offshore data is typically less reliable.
I will switch gears and go into some of the interesting things we saw yesterday. One item came from Huntsville's Hytop radar. The PGLM showed a jump in activity at 0016 UTC and then decreased. This was followed by a significant increase in the radar reflectivity at 0027 UTC at the -20 C isotherm level. This raised the question, "Why did was the lightning jump followed by an intensification in the radar signature?" This leads into the discussion of how lightning jumps precede severe weather. Typically, a jump will occur and then the lightning activity will decrease ahead of the severe weather event as the storm core descends. However, yesterday, we saw the echo tops increase after the lightning jump. This is likely a case of larger hail aloft developing, which results in weaker charging in the updraft. The result is less lightning, but stronger reflectivities.
Another fun example is in the image below.
This screen capture shows the PGLM flash extent density (as the 8 km blocks) along with the NLDN cloud-to-ground strike locations with the '-' and '+' symbols in yellow. Notice how the majority of storms have NLDN strikes co-located with PGLM flashes. The exception is the circled storm moving into the extreme western section of the Huntsville (HUN) county warning area. This storm was just developing and the PGLM began detecting lightning activity ahead of the NLDN strikes. The forecasters liked how this feature can be useful in detecting the initiation of convective cells and I pointed out the utility of the advanced lead time for the first cloud-to-ground strike for public products like airport weather warnings.
The second image, below, is an interesting combination of the PGLM with the IR satellite data that I have not seen used previously by forecasters.
I was interested in seeing this particular overlay and asked about its utility. The response was for monitoring the location of the convective cores. The IR shows the coldest cloud tops where convection is occurring, although cirrus can obscure what is happening below. By overlaying the PGLM over the IR imagery, the PGLM focuses the forecasters attention on the actual cores.
Overall, this was a good real-time event that generated good discussions throughout the evening.
I will add a few general comments and then include two images from the event. Overall, like the 24 May 2008 archived case, the impression was that the PGLM served as a good situational awareness tool. I then asked about the resolution of the product. Again, the response is that forecasters always want better resolution. In this case, though, the PGLM was adequate for what it was being used to analyze. One comment was that the PGLM was useful to see the convective cores, particularly during initiation. The NLDN has been used in this role, but the PGLM can give a few extra minutes lead time on initiation since most storms initiate with intra-cloud lightning before cloud-to-ground strikes. Another interesting comment after the event was that the PGLM could be very useful for coastal WFOs where the offshore data is typically less reliable.
I will switch gears and go into some of the interesting things we saw yesterday. One item came from Huntsville's Hytop radar. The PGLM showed a jump in activity at 0016 UTC and then decreased. This was followed by a significant increase in the radar reflectivity at 0027 UTC at the -20 C isotherm level. This raised the question, "Why did was the lightning jump followed by an intensification in the radar signature?" This leads into the discussion of how lightning jumps precede severe weather. Typically, a jump will occur and then the lightning activity will decrease ahead of the severe weather event as the storm core descends. However, yesterday, we saw the echo tops increase after the lightning jump. This is likely a case of larger hail aloft developing, which results in weaker charging in the updraft. The result is less lightning, but stronger reflectivities.
Another fun example is in the image below.
This screen capture shows the PGLM flash extent density (as the 8 km blocks) along with the NLDN cloud-to-ground strike locations with the '-' and '+' symbols in yellow. Notice how the majority of storms have NLDN strikes co-located with PGLM flashes. The exception is the circled storm moving into the extreme western section of the Huntsville (HUN) county warning area. This storm was just developing and the PGLM began detecting lightning activity ahead of the NLDN strikes. The forecasters liked how this feature can be useful in detecting the initiation of convective cells and I pointed out the utility of the advanced lead time for the first cloud-to-ground strike for public products like airport weather warnings.The second image, below, is an interesting combination of the PGLM with the IR satellite data that I have not seen used previously by forecasters.
I was interested in seeing this particular overlay and asked about its utility. The response was for monitoring the location of the convective cores. The IR shows the coldest cloud tops where convection is occurring, although cirrus can obscure what is happening below. By overlaying the PGLM over the IR imagery, the PGLM focuses the forecasters attention on the actual cores.Overall, this was a good real-time event that generated good discussions throughout the evening.
EWP daily briefing... 6/10/2010
SPC has issued a moderate risk over the area formerly known as "Big-12 Country" (ie - Nebraska/Colorado border). The plan will be similar to what we have done for previous IOPs with the first half of the day spent monitoring the GOES-R products for convective initiation and the second half of the day monitoring the MRMS products during warning operations.
During the briefing, Lee discussed the previous day. Unfortunately the area we targeted yesterday did not have much happen in terms of UWCI due to a widespread area of cirrus. We were able to see some overshooting top detections over northern Alabama, but they were not really associated with a lot of severe weather. There was only one thermal couplet detection but was not used by the forecasters during warning operations because they did not notice it. Most of yesterday's IOP was focused on the PGLM product, which Geoffrey Stano will post on in more detail in an upcoming post, and we got some very good feedback from that, as well as in the case example that Geoffrey has already discussed. Lee did show an area over NM/CO where the UWCI was showing 30-35 minute lead times on the first occurrence of a 35 dBZ echo on composite radar.
One important thing I noted during the discussion is that the forecasters need some sort of tool to help them forecast, and/or diagnose areas of severe winds. Right now they mentioned they have nothing that really helps them and it is really hard for them to warn for severe wind. Something to keep in mind for possible applications of GOES-R data, but I know this would be a difficult task. Nonetheless, it is an area where a obvious void in forecaster tools are present.
Wednesday, June 9, 2010
Discussions from the 24 May 2008 Archived Case
As I mentioned in the previous pseudo-GLM post, there were several good lines of discussion during and after the event was run.
I had asked what the forecasters felt about the pseudo-GLM as a whole and how the WFOs use lightning now. One common response was that lightning is a "good to know" product, particularly for situational awareness. Lightning is good for outdoor events and monitoring lightning initiation. The pseudo-GLM improves the lead time on the first cloud-to-ground strike as most storms begin with intra-cloud lightning before the first cloud-to-ground strike. The pseudo-GLM also can assist in radar poor regions as well as gauge the intensity of the lightning activity.
Additionally, I was a little too concerned with influencing the forecasters' thought process during the event. As a result the lightning jump described in the previous post was not readily seen. During the post analysis, the discussion focused on the lightning jump and how it did help flag the southern cell a few minutes earlier than radar alone. The post-event analysis helped solidify the connection between the lightning jump and what was observed on radar.
I also asked about how the 8 km resolution worked for the forecasters. The main response is that everyone always prefers higher resolution. With that said, this resolution should be good enough to distinguish between the updraft and forward flank downdraft region of storms. It also can show the cores of individual storms.
Another comment by the forecasters was the interest in seeing total lightning during winter storms. They wish to determine if there is convective snow and they have found that the National Lightning Detection Network (that detects cloud-to-ground strikes) rarely indicates lightning. Knowing that a snow event is convective could lead to a doubling of the estimated snowfall amount.
One of the final topics I asked about was how to better include lightning data in public products. Currently, the WFOs do not issue "lightning warnings" like the 45th Weather Squadron does for Kennedy Space Center and Cape Canaveral Air Force Station. Also, the typical warning for severe thunderstorms or tornadoes starts with, "Doppler radar has indicated ..." We discussed how lightning wording could be added and I included some of my conversations with the Huntsville, AL and Melbourne, FL WFOs. There is the potential to state that, "A GLM lightning jump was detected ..." but this incurs problems with interpretation by the public. An excellent suggestion by the forecaster participants was to include the phrase, "... GLM lightning trends indicate a higher confidence that this storm is becoming severe or producing a tornado." This helps convey confidence in the forecast as well as adding additional lightning awareness.
Tomorrow I will update the blog with the discussions and comments from the real-time operations we performed over the Huntsville, Alabama domain today.
I had asked what the forecasters felt about the pseudo-GLM as a whole and how the WFOs use lightning now. One common response was that lightning is a "good to know" product, particularly for situational awareness. Lightning is good for outdoor events and monitoring lightning initiation. The pseudo-GLM improves the lead time on the first cloud-to-ground strike as most storms begin with intra-cloud lightning before the first cloud-to-ground strike. The pseudo-GLM also can assist in radar poor regions as well as gauge the intensity of the lightning activity.
Additionally, I was a little too concerned with influencing the forecasters' thought process during the event. As a result the lightning jump described in the previous post was not readily seen. During the post analysis, the discussion focused on the lightning jump and how it did help flag the southern cell a few minutes earlier than radar alone. The post-event analysis helped solidify the connection between the lightning jump and what was observed on radar.
I also asked about how the 8 km resolution worked for the forecasters. The main response is that everyone always prefers higher resolution. With that said, this resolution should be good enough to distinguish between the updraft and forward flank downdraft region of storms. It also can show the cores of individual storms.
Another comment by the forecasters was the interest in seeing total lightning during winter storms. They wish to determine if there is convective snow and they have found that the National Lightning Detection Network (that detects cloud-to-ground strikes) rarely indicates lightning. Knowing that a snow event is convective could lead to a doubling of the estimated snowfall amount.
One of the final topics I asked about was how to better include lightning data in public products. Currently, the WFOs do not issue "lightning warnings" like the 45th Weather Squadron does for Kennedy Space Center and Cape Canaveral Air Force Station. Also, the typical warning for severe thunderstorms or tornadoes starts with, "Doppler radar has indicated ..." We discussed how lightning wording could be added and I included some of my conversations with the Huntsville, AL and Melbourne, FL WFOs. There is the potential to state that, "A GLM lightning jump was detected ..." but this incurs problems with interpretation by the public. An excellent suggestion by the forecaster participants was to include the phrase, "... GLM lightning trends indicate a higher confidence that this storm is becoming severe or producing a tornado." This helps convey confidence in the forecast as well as adding additional lightning awareness.
Tomorrow I will update the blog with the discussions and comments from the real-time operations we performed over the Huntsville, Alabama domain today.
24 May 2008 Archived Lightning Case
With no lightning in any of our total lightning domains during operations Monday and Tuesday, the forecasters focused on the archived case from 24 May 2008 near Enid, Oklahoma. This case has served as a good introduction to the pseudo-GLM flash extent density product ahead of the real-time operations that have been taking place Wednesday afternoon. This event was interesting to go through, with a northern cell in Garfield County and a later, southern cell in Kingfisher County. The scenario starts with the northern cell already active. Both cells showed strong lightning jumps ahead of intensification.
For the northern cell, the jump preceded the formation of a strong rotation couplet. However, storm reports did not indicate an observed tornado or severe weather. I had remarked after the event that this was one of the stronger jumps I had seen without a severe weather report. Most of the forecasters warned on this storm due to the radar velocity signature, but the lightning jump helped add confidence. Potentially, severe weather occurred, but due to the location of the storm nothing was observed.
The southern cell demonstrated the utility of total lightning for both lightning safety and severe weather operations. As the southern cell began to develop, the pseudo-GLM indicated lightning activity 5 minutes before the first cloud-to-ground strike. Initially the pseudo-GLM was showing a flash density of 6 flashes at 1902 UTC. This gradually increased for the next 8 minutes and then demonstrated a rapid jump to 86 flashes by 1919 UTC. This occurred 8 minutes ahead of the first reported tornado just west of Lacey, Oklahoma at 1927 UTC. During the post analysis, this lead time was significant for the event as the radar velocity signature was weak at 1921 and was just showing signs of a couplet at 1926 UTC. The reflectivity was showing some signs of a hook at 1921.
I feel the discussions from going through this event with four forecasters were the best results. I will follow-up with this in a subsequent post.
For the northern cell, the jump preceded the formation of a strong rotation couplet. However, storm reports did not indicate an observed tornado or severe weather. I had remarked after the event that this was one of the stronger jumps I had seen without a severe weather report. Most of the forecasters warned on this storm due to the radar velocity signature, but the lightning jump helped add confidence. Potentially, severe weather occurred, but due to the location of the storm nothing was observed.
The southern cell demonstrated the utility of total lightning for both lightning safety and severe weather operations. As the southern cell began to develop, the pseudo-GLM indicated lightning activity 5 minutes before the first cloud-to-ground strike. Initially the pseudo-GLM was showing a flash density of 6 flashes at 1902 UTC. This gradually increased for the next 8 minutes and then demonstrated a rapid jump to 86 flashes by 1919 UTC. This occurred 8 minutes ahead of the first reported tornado just west of Lacey, Oklahoma at 1927 UTC. During the post analysis, this lead time was significant for the event as the radar velocity signature was weak at 1921 and was just showing signs of a couplet at 1926 UTC. The reflectivity was showing some signs of a hook at 1921.
I feel the discussions from going through this event with four forecasters were the best results. I will follow-up with this in a subsequent post.
EWP daily briefing... 6/9/2010
Before the official briefing started, one of the forecasters mentioned to Lee Cronce and myself the idea of creating a filter for the CI product where cirrus is present so that the forecasters will know when the product will not be able to make any nowcasts, similar to how the radars have a certain color for areas where range folding is occurring. He mentioned that at some times they cannot understand why the product is not producing nowcasts in obvious situations of CI unless someone looks up the cloud type output for them. This was noted by Lee as a possibility for future input into the product's output.
24-hour thermal couplet detections and severe reports for 7 June 2010
During the briefing Lee presented some scan by scan output from the UWCI product over Wyoming during the 6/7 IOP. He mentioned that the first signal in the UWCI was seen at 2032 UTC, with more widespread signals occurring at 2045 UTC and beyond. The area of interest was actually located between two radars where coverage is fairly limited and the UWCI provided some information on the initiation about 15 minutes prior to detection on radar. He also showed the 24-hour thermal couplet detections and severe reports from the same event (see images above). There were a lot of detections associated with the severe reports, including one that was co-located with and prior to a report of a tornado near Scottsbluff, NE.
One of the forecasters mentioned the possibility of a GOES-R storm top divergence product. He mentioned how this would be very useful in determining storm characteristics in warning operations. I mentioned Bob Rabin's work with current GOES WV winds in producing real-time winds at various levels by tracking features in the WV imagery. From these winds he is able to calculate divergence, vorticity and wind speed contours. I showed them real-time examples from the website provided by Bob Rabin at http://cimss.ssec.wisc.edu/mesoscale_winds/. The forecasters seemed very interested in this and mentioned interest in demonstrating this in future experiments. I also made sure to point out that with GOES-R's great improvement on spatial and temporal resolution, these products will be much more accurate and will be able to capture smaller scale features. I also talked about GOES-R's increased capability for object tracking.
During the weather discussion I showed the forecasters the UW-CIMSS simulated satellite/observed satellite comparison page to see how well the NSSL-WRF was representing the day's weather. It seemed to be doing fairly well so I showed the simulated lightning threat product to see what the NSSL-WRF was showing for the possibility of lightning over the CONUS region. There seemed to be the possibility of some lightning occurring over the Nashville area later on this evening, so following the weather discussion for the day we decided to localize near Huntsville, AL for the possibility of real-time PGLM operations.
24-hour thermal couplet detections and severe reports for 7 June 2010
During the briefing Lee presented some scan by scan output from the UWCI product over Wyoming during the 6/7 IOP. He mentioned that the first signal in the UWCI was seen at 2032 UTC, with more widespread signals occurring at 2045 UTC and beyond. The area of interest was actually located between two radars where coverage is fairly limited and the UWCI provided some information on the initiation about 15 minutes prior to detection on radar. He also showed the 24-hour thermal couplet detections and severe reports from the same event (see images above). There were a lot of detections associated with the severe reports, including one that was co-located with and prior to a report of a tornado near Scottsbluff, NE.
One of the forecasters mentioned the possibility of a GOES-R storm top divergence product. He mentioned how this would be very useful in determining storm characteristics in warning operations. I mentioned Bob Rabin's work with current GOES WV winds in producing real-time winds at various levels by tracking features in the WV imagery. From these winds he is able to calculate divergence, vorticity and wind speed contours. I showed them real-time examples from the website provided by Bob Rabin at http://cimss.ssec.wisc.edu/mesoscale_winds/. The forecasters seemed very interested in this and mentioned interest in demonstrating this in future experiments. I also made sure to point out that with GOES-R's great improvement on spatial and temporal resolution, these products will be much more accurate and will be able to capture smaller scale features. I also talked about GOES-R's increased capability for object tracking.
During the weather discussion I showed the forecasters the UW-CIMSS simulated satellite/observed satellite comparison page to see how well the NSSL-WRF was representing the day's weather. It seemed to be doing fairly well so I showed the simulated lightning threat product to see what the NSSL-WRF was showing for the possibility of lightning over the CONUS region. There seemed to be the possibility of some lightning occurring over the Nashville area later on this evening, so following the weather discussion for the day we decided to localize near Huntsville, AL for the possibility of real-time PGLM operations.
Tuesday, June 8, 2010
Thermal Couplet detection prior to spotter funnel report
An interesting thermal couplet case not within the assigned WFO emulations. At 2202 UTC a thermal couplet was detected right near the border of northeastern KS/northwestern MO within the EAX CWA. At that time, no LSRs indicated any severe reports other than flooding. Approximately 15 minutes later a report came in of a funnel cloud via a spotter network. As an additional note, there is currently no severe thunderstorm warning for the storm with the detected thermal couplet. Perhaps this would be a good case of increasing forecaster confidence for warning with the associated thermal couplet detection?
Now 2239 UTC, and the cell that produced the thermal couplet is now tornado warned
TX Panhandle CI in the HWT-EWP 6-8-10
Today in the NOAA HWT EWP in Norman we have been watching a line of cu over the TX Panhandle. At 1932 UTC we first noticed the CI "pre-cloud growth" and the "likely" indications. It was interesting to note however that the "likely" was associated with cloud-top cooling rates in the -4 to -7 range, but the "pre-cloud growth" was associated with greater values of cloud-top cooling rates of around -9. Eventually the area of -9 became the first convective initiation spot, and those values increased to -14 before we saw the first 35 db echo. The first 35 db echo showed up at 1955 UTC, which was 23 minutes later. At 2025 UTC a 1" hail report was logged with that same storm.
One other point to note was that we were monitoring the products on the web site (http://cimss.ssec.wisc.edu/snaap/convinit/quicklooks2.php) and estimated that the CI indications were approximately 3 minutes faster than the LDM feed into AWIPS.
One other point to note was that we were monitoring the products on the web site (http://cimss.ssec.wisc.edu/snaap/convinit/quicklooks2.php) and estimated that the CI indications were approximately 3 minutes faster than the LDM feed into AWIPS.
Identified Overshooting Top
The above overshooting top was identified at 2032 UTC outside the current IOP area of Wichita and Topeka, Kansas, with the associated severe thunderstorm warning issued at 2038 UTC by the Shreveport WFO. However, unsure what the forecasters were thinking when issuing the warning, and whether the OT product would have been helpful in their decision.
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