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.

Simulated lightning threat over western US for fire weather applications

NSSL-WRF Simulated lightning threat 3 21-hour forecast (contoured) and hourly NLDN lightning detections (red symbols) valid at 2100 UTC on 9 June 2010
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.

EWP daily briefing... 6/10/2010

SPC Day-1 outlook for 10 June 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.