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.

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.

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...

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."

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.

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.