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

24-hour severe reports from 16 June 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)

24-hour UWCI nowcasts for 16 June 2010.
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

EFP QPF group discussing simulated WV imagery from the 00Z run of the NSSL-WRF on 17 June 2010
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.

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.

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.

EWP daily briefing... 6/15/2010

Psuedo-GLM total lightning flash extent density overlaid with OKLMA flash contours and associated radar reflectivity for the OKC flood event at 1100 UTC on 15 June 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.

SPC Day-1 outlook for 15 June 2010
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.