DSS – EWP Blog

Severe Weather over western Pennsylvania

Posted in DSS, Lightning Stoplight, LightningCast, SPG2026 on May 13, 2026 by Kevin Thiel.

On Day 3 Wednesday of the Hazardous Weather Testbed, we monitored weather for the Pittsburgh CWA (PBZ), and in particular lightning and severe weather that could affect the Pittsburgh Mimosa Festival and the Allegheny Caribbean Carnival. We issued several SVRs that ended up verifying with multiple hail reports of 1.0” in diameter (quarter size) and a few damaging wind reports in northern WV. See SPC reports further below.

The main radar products that were used for severe weather decision making were the 0.5° Base Reflectivity and Base Velocity products, the MRMS @-20C, Vertically Integrated Ice, and MESH. LightningCast V2 and Stoplight V2 were also used to support DSS activities at the two festivals mentioned above. At the beginning of the event at 18Z, thunderstorms were already impacting the two festivals as seen on the Time-Series plot of LightningCast with observed GLM flash counts and near 100% lightning probability at the exact locations.

Figure 1 above shows the probability of lightning at the location of the Allegheny Caribbean Carnival from LightninCast V2 (green line) and the observed flash counts from the Geostationary Lightning Mapper (GLM) instrument. Notice that the second spike in lightning probabilities did not result in lightning activity detected at the exact location as shown by the lack of GLM flash counts. In this second spike in lightning probability, the LightningCast V2 had a small false alarm than the V1 product.

Figure 2 above shows the Pittsburgh Mimosa Festival experienced two rounds of thunderstorms, one between 18Z and 19Z and a second round between 1945Z and 20Z.

We also monitored the Stoplight V2 product to give the all clear message that the lightning threat had ceased.

Figure 3 above shows the Stoplight product indicating the cessation of lightning and when it was good to give the all clear message that activities could be resumed.

Figure 4 above shows the MRMS Isothermal Reflectivity product @-20C which often shows the most significant storms and the storms that might contain hail alongside the Vertically Integrated Ice. SVRs polygons are also shown to indicate where SVRs were issued.

Figure 5 above shows the SPC’s Severe Weather reports from Wed May 13 2026. Four hail reports of quarter size were reported in western Pennsylvania and three wind damage reports in northern WV.

-Hurricane Specialist

SPG Blog Post Day 3

Posted in DSS, Lightning Stoplight, LightningCast, SPG2026, Synthetic GXI on May 13, 2026 by Kevin Thiel.

Disclaimer: I had alot of internet and AWIPS issues today :-(. So I mostly got experience with DSS procedures. After IT helped me (Thank you!!) I was able to get some warnings out. I’m sorry for the issues!

Today, we looked at a slight risk out in Idaho. A relatively strong low pressure system with an associated cold front moved through, providing decent parameters for wind concerns in the PIH CWA. This event featured some initially shallow pop-up convection, that quickly blew up to storms that were producing 70-85mph winds over eastern Idaho! Very interesting setup, because the only really notable instability initially noticed was the impressive DCAPE (1000-2000 J/kg), and decent lapse rates. Was hard to notice before reports rolled in, since the storms really did not look impressive on satellite or radar.

Figure 1: WVT (left: colored color map, right: greyscale)

During the quiet period of the event in Idaho, after sending out Slack messages and a briefing slide to partners, I played around with the color maps for the WVT product. This one is based off of a WV map product that SLC uses. You can see the seabreeze move in pretty well during this time frame (lighter green = moisture).
- I sent this color map in the Slack group!

Figure 2: LightningCast Stoplight over PIH

LightningCast was great today for having multiple DSS events!
- This is an image where I made the colormap slightly transparent so you can see the imagery underneath the stoplight colors a bit more clearly.
- What isn’t visible here, was that I had the “0-10” range blinking, to help grab attention quickly.
- I also used the SuperDashboard today! I really liked it – especially when I had AWIPS issued and had to rely on desktop products more than AWIPS.
  - I oddly enough couldn’t get both events on the dashboard at the same time? Both events existed and had links. At first, it was because they started at different times because I had entered the wrong time zone. But, when both events should have been active, only one appeared. The links themselves sent to my email, however, worked just fine!

-Kelvin-Helm

DSS: Max Road Fire

Posted in DSS, Lightning Stoplight, LightningCast, SPG2026, SZA Imagery on May 12, 2026 by Kevin Thiel.

During Day 2 of the Hazardous Weather Testbed, we provided mock-DSS to the Max Road Fire located in South FL along the Broward and Miami-Dade county line. Since this was a DSS event, we evaluated the two most important products related to lightning onset and cessation, LightningCast V1 vs V2 and the Stoplight product, at the fire location making sure firefighters had ample lead to time to seek shelter before lightning struck the area. We also requested an on-demand dashboard display of LightningCast V1 and V2 at the exact fire location to help monitor probability trends of lightning activity.

Figure 1 (above): shows an animation of LightningCast V1 (images on the left) vs Lightning V2 (images of the right). Notice the higher probabilities indicated by V2 on the right of up to 70% vs 50% on the left. It turned out that LC V2 provided a much longer lead time of lightning onset just outside the range ring over the fire location.

Figure 2 (above): shows the Spotlight V2 product (GLM FED + ENTLN combined) confirming lightning activity at 1921Z outside of the 8-mile radius from the fire location.

Figure 3 (above): shows a time series plot showing the probability trends of lightning at the exact location of the fire and also the maximum probability of lightning within the 8-mile radius of the fire location. Lightning was detected by the GLM instrument around 2041Z (image below) when the LightningCast probability trends showed a rapid upward trend in probabilities (image above)

Lastly, the Solar Zenith Angle imagery below provided a clearer view of the texture of the clouds right on the coast just north of Miami roughly an hour before sunset when compared to the traditional imagery on the right.

Figure 1: Solar Zenith Angle imagery at 606 PM EDT, almost two hours before sunset. Sunset at Miami (MIA) was at 7: 58 PM as shown on the Climate Daily Report (CLI) from NWS MFL.

Hurricane Specialist

Tuesdays HWT

Posted in DSS, Lightning Stoplight, LightningCast, SPG2026, SZA Imagery on April 28, 2026 by Kevin Thiel.

Main issue today was to do IDSS near Delhi MS. We were using lightning cast and lightning stoplight. We were also issued a few warnings. Fortunately, we had a storm move over the region so we were quite busy for at least an hour or so.

Our team created some loops of the data. A long loop of GLM and ltg prob is below …

The blinking circle was our DSS site. Lena was our “emergency manager” for the day.

We had thorough conversations with Lena and Kevin regarding using the tow lightning products in operations. We agreed that the products are very useful, but would not work all that well to send these products directly to our partners.

Note that we had a thorough conversation on the slack channel and you can follow the “blow by blow” discussions there.

We also had a great conversation with Lena regarding how we interact with our emergency managers.

Regarding Lightncast, I believe that the planview products are good. I prefer looking at the imagery like this though >>>>

Note that the data probabilities on the awips image above go from 0% to 100 percent. Why is it important to show the data this way instead of contours? The reason is you can see the VERY beginning of when the ltg probs start to show up. Using contours, you have to wait until the 10% prob shows up. Note that I do not have sat pix imagery overlaid, The reason why I do this with AWIPS is I can have the sat pix data opened up in another panel and use the cursor to read the data. Also the contours (or the image for that matter) would get “lost” (or buried) within the colors of the sat pix imagery.

We used the Lightning Stoplight product today. This was helpful in letting us know when the last flash occurred in the 10, 20 and 30 increment time frame. However I am hesitant with sharing this directly with the EMs.

I envision that the Stoplight product and the LightningCast product will be married in the future, and this will make these two products more useful.

I can not say enough how valuable the lightningcast product is. Prior to this we did not have a good idea when lightning would be a threat, and would have to carefully watch radar data and do cross sections or monitor to -10C level. With lightningcast, you have the probabilities calculated for you in real time every minute (mesosector) or every 5 minutes for CONUS.(However waiting 5 minutes is wayyyyyyyy toooooo lonnnnnnnnnnnnng.

We talked about the SZA product. This is a no brainer and this satellite product should be implemented operationally as soon as possible. Being able to see the detail in the sat pix data towards sunset is priceless.

-Mesovortex

April 28th Hazmat DSS

Posted in DSS, LightningCast, SPG2026 on April 28, 2026 by Kevin Thiel.

Warm Sector Growth: Jaxson MS

The day started this morning with thunderstorm development from the overnight outflow boundary that remained in the southeast. This was quickly replaced by 1500 to 2500 j/kg of MUCAPE. There was 40 kts of shear, which would help to sustain any pre-frontal convection. With dewpoints in the warm sector approaching 75° in Northeast Louisiana. A very shallow cap was present, but quickly eroded from solar heating. Once the cap was eroded we got rapid growth of a thunderstorm complex. This complex moved slowly across Northeast Louisiana and Central Mississippi throughout the afternoon.

DSS operations for a Hazmat: Northeast Louisiana

We coordinated with a hazmat cleanup site that was near the Louisiana/Mississippi border. The emergency manager had required the heads up on lightning within a 10 mile radius of the location. In the figure below we see a developed thunderstorm complex that is moving west to east across the segment of the 10 mile radius. The OCTANE product allowed us to build confidence on a strengthening thunderstorm near the hazmat clean up area. We can see a very moist inflow on the southwestern edge of the complex. It was good that we were able to see a very distinct inflow because we received a report of 1.75” hail. This inflow allowed the thunderstorm to continue to strengthen.

Cessation of Lightning:

The biggest question the public or our partners will ask, is when will the lightning end. We used a variety of tools to determine when it is good to give the all clear. They were the lightning stoplight, lightning cast, and radar. With this event we heavily relied on the stoplight and radar, due to a lag in the lightning cast probabilities. While lightning cast had identified lower chances it would still put over 50% probabilities when the threat had been over for 30 minutes.

The first graphic shows a quick downward response to the cessation of lightning. However, on the second graphic we see lightning probabilities remain elevated for a long period of time. Using other tools like lightning stoplight and radar, it makes no sense that we should be holding the all clear until the probabilities go near 0. While lightning cast may not be perfect, it is another tool in the toolbox.

-Blizzard

Day 4- Large Hail in Texas

Posted in DSS, GREMLIN, LightningCast, SPG2025 on June 5, 2025 by Kevin Thiel.

Conditions were favorable for severe thunderstorms across west Texas on Thursday, June 5, 2025. High instability and shear led to rapid development thunderstorms across the high plains. Initially, a cluster of thunderstorms congealed into one which then split into two. The right mover went on to produce at least 3” in diameter hail and wind gusts in excess of 72mph. Due to the poor radar coverage in west Texas, GREMLIN was useful in supplementing radar and MRMS data. GREMLIN showed features I hadn’t seen in the start of the week, including bean-shaped storms and double updrafts that later split into two storms.

GREMLIN had some odd things occur too. ECONUS GLM did not represent the lightning that was occurring with these storms and it is believed that this may have degraded GREMLIN. In the loop below, ECONUS GREMLIN produced a fictitious cell northeast of the left and right movers. It also lagged a bit before it showed two strong cells, especially the southern storm.

Four Panel-GREMLIN EMESO-1 (top left,) MRMS -10c (top right,) GREMLIN ECONUS (bottom right,) and CH07 (bottom left.) In this example you can see the stronger storm to the south

Here is a single image of the bean shaped cell that produced at least 3” hail.

LightningCast was useful for situational awareness and messaging our partners for the DSS event. We noticed V2 was a little better at maintaining the high probability of lightning (greater than 90%) than V1 in mature convection.

LightningCast proved to be useful for our fictitious DSS event in west Texas. V2 was faster to increase the probability of lightning prior to lighting occurring at the event (below.) It was also faster to show lightning cessation. There was a brief lull in lightning mid-way through the operational period and both V1 and V2 showed about a 20 min lead time of the probability of lightning decreasing in the next hour. V2 stayed slightly elevated compared to V1, but both highlighted that there was still a high probability of lightning in the next hour.

Lastly, OCTANE (below) proved to be useful again in warning operations. Robust, mature convection was ongoing and while it was “off to the races” in west Texas, the speed and divergence products continued to the tight gradient of speed divergence. We noticed that the compressed color scale was more “eye catching” to show the tight gradient. Below is a picture of the speed/direction divergence product with sampling turned on. The overshooting top was at an impressive -85C with winds out of the west at 50 mph. In this example, the gradient on the west side of the storm helped maintain our confidence of a powerful storm.

– Eagle

Supercells in Southwest Kansas

Posted in DSS, GREMLIN, LightningCast, OCTANE Speed Sandwich, SPG2025 on June 5, 2025 by Kevin Thiel.

Convection crossing into Hamilton County

Pretty much right at the start of operations, convection over southeast Colorado began pushing east into Hamilton County, KS. Looking at the first gif below (Figure 1 with the Octane 4-panel), you can really see a persistent divergence signal as the storm continued into the county. Additionally, probsevere (located in the top left panel) was pretty high, maxing out above 90%. Next, looking at the LightningCast panels in Figure 2, you can see the lightning jump occurring right as it crosses over the county line. Utilizing these products together and noting radar showing a mid-level meso with 50 dBZ over 35kft, we felt confident to go ahead and issue a Severe Thunderstorm Warning for this cell (shown in Figure 3).

Figure 1: Octane 4-panel with ProbSevere overlaid in the top left panel

Figure 2: LightningCast v1(left) and v2(right) with GLM

Figure 3: Radar Reflectivity with the Severe Thunderstorm Warning

GREMLIN (top left panel in Figure 4 below) did a pretty good job showcasing this cell, as well as another strong cell just to the southwest, however compared to MRMS (top right panel), it didn’t capture the stronger reflectivities as well, and was approximately 5-10+ dBZ off. So if I didn’t have radar access and could only rely on GREMLIN, I may not have felt as strongly about issuing a SVR.

Figure 4: GREMLIN 4-panel

I didn’t grab images of this, however later on, there was a clear decrease in the lightning activity, with noticeably lower divergence and cloud top cooling. This gave me the confidence to cancel my warning early.

Octane and ProbSevere

Later on, the same cell over Hamilton County began slightly cooling again, with ProbSevere noting 59% probabilities (top left panel in Figure 5). Additionally, there was a very clear mesocyclone noted in Figure 6. Using just these two products, I may have been inclined to issue at least a SVR warning. However Octane wasn’t noting much, if any, cloud top divergence or cloud top cooling. Lightning also didn’t look very impressive either. Noting this, I strayed away from any warning issuance (especially considering radar was sampling this storm at 12.5kft), which I think was a good call, at least for this time.

Figure 5: Octane 4-panel with ProbSevere overlaid in the top left panel

Figure 6: Storm Relative Velocity

LightningCast Dashboard for the DSS Event in Dodge City

Closer to the end of operations, the LightningCast dashboard (Figure 7) started showing higher probabilities of lightning, with the Max prob for a 10-mile radius showing 77%, v1 at 45%, and v2 at 30%. There were two supercells several counties west of the event that were expected to track southeast, missing the venue, however with the dashboard and CAMs showcasing the potential for lightning to reach the event, we were confident enough to fill out a DSS form and graphic (shown in Figure 8) with this information.

Figure 7: LightningCast Dashboard

Figure 8: DSS Graphic

It should be noted that v2 only highlights a 30% probability, and later on was ~44% lower than v1 (v1 was at 76%, with v2 at 32%. With this being at the end of operations, we couldn’t see if lightning actually occurred at the event, but I’d be interested to see if v2 actually had a better grasp on the convection tracking southeast and missing the event altogether, or if v1 showcasing the higher probabilities was the better option.

Final Thoughts from Day 4:

The Octane product really shined today, both in increasing my confidence to issue a SVR warning, and in talking me down from issuing a separate warning. I’ve been sold on the Stoplight colorcurve, with no smoothing (top right panel) coming out on top.

– Fropa

Southwest Texas Lightning Product Performance

Posted in DSS, GLM, LightningCast, SPG2025 on June 5, 2025 by Kevin Thiel.

Lightning, and GOES-East vs. GOES-West

Observation 1: GLM discrepancies between satellites

Left: GOES-East LightningCast v1 & GLM FED Right: GOES-East LightningCast v2 & GLM FED 1836 UTC – 1931 UTC 5 June 2025 in southwest Texas

GOES-West GLM 1911 UTC – 1933 UTC 5 June 2025 in southwest Texas (LightningCast outside the domain)

The Midland-Odessa (MAF) forecast area (and nearby upstream areas in Mexico) sits in a weird position where it is well within the GOES-East CONUS domain, but on the edge of the GOES-West CONUS domain (and thus outside the CONUS LightningCast domain), yet within the GOES-West full disk domain. The above images show GLM observations in southwest Texas from both satellites, where GOES-East shows far less lightning (and a downward trend) while GOES-West showed significantly more lightning at the same time (also with a downward trend, but still indicating a stronger storm).

Observation 2: GOES-East LightningCast performance within areas where GLM FED is underestimating

While LightningCast data is not available from GOES-West in this portion of southwest Texas to compare GOES-West v1 vs. v2 as well as East vs. West, the quality of the GOES-East LightningCast product in areas with potentially degraded GLM observations raises an interesting question about how the models perform in this situation.

In the first GOES-East LightningCast loop shown above, version 1 and version 2 generally seem to perform very similarly, likely because of poor radar coverage and data availability. (See RQI image for the area below). Version 1 picks up on a contour of 70% ProbLightning for a developing storm to the northwest of our main cell at 1856 UTC, roughly the same time as Version 2, giving roughly a 20 minute lead time, with the first strike via GLM around 1916 UTC. Version 1’s 70% contour is larger and remains larger than version 2 for the first 10 minutes or so, before both products begin matching closely around the time of first lightning detection. Version 2 then quickly begins downtrending on that cell, seeming to pick up on lightning cessation prior to version 1 does.

Observation 2.5: GOES-East LightningCast DSS Dashboard

This storm impacted our DSS event. At 1955 UTC, DSS was provided to the partner that “lightning will be within 10 miles of the event within the next 30 minutes (by 2030Z) from a storm roughly 30 miles south-southwest of the location (the larger, southernmost storm in the GOES-East loop), a Severe Thunderstorm Warning has been issued for that storm just south of them but the warning doesn’t encompass the event, and that additional convection is going up north of the event, which may also bring lightning within the 10 mile range of the event.”

GOES-East LightningCast DSS Dashboard.

The decision to contact the partner about the DSS event at 1955 UTC was made with the help of the LightningCast DSS Dashboard, which had a max probability of lightning within the 10 mile radius of the event at 90% at the time of the contact. They were told they had less than 30 minutes before lightning was within 10 miles, and 20 minutes after that call, the first GLM strike was observed in that radius. Negating the time it took to fill out the DSS form online in comparison to picking up the phone, the DSS provided to the partner based on the dashboard output was 10 minutes late on onset, but could have been spot-on if the DSS call was provided immediately after the 10-mile radius probability reached 90% instead of waiting to see persistence before calling the partner.

Back to observation 2: GOES-East LightningCast performance within areas where GLM FED is underestimating

Also in the GOES-East LightningCast loop, there is a lower probability contour in the farthest northwest corner of the image at the beginning of the loop. Both versions pick up on it, and both versions go back and forth between characterizing this small bullseye area as continuous/connected to the two storms to its southeast and discrete. Version 2 indicates 50% probabilities briefly, while Version 1 does not. Both have probabilities dropping <10% at the same time, and lightning was never observed.

MRMS radar quality index

– prob30

Lightning Dashboard IDSS

Posted in DSS, LightningCast, SPG2025 on June 5, 2025 by Kevin Thiel.

For Day 4, we were DDC. There was an outdoor event ahead of the convection, and prob lightning did a great job 1) detecting some convection ahead of it and 2) showing that it would be east of our IDSS event.

The animated GIF above shows both versions of the lightning cast, with the outdoor event marked by the “Home”. In this case, both versions accurately predicted lighting (white dashes), and also showed it staying east of the event.

– Updraft

Warning Without Radar Data in Northern New Mexico

Posted in DSS, GREMLIN, LightningCast, OCTANE Speed Sandwich, SPG2025 on June 4, 2025 by Kevin Thiel.

Day 3 of the testbed offered a unique opportunity to issue real-time warnings without access to radar data. Having never been in such a situation before, it was an eye-opening experience.

Mesoanalysis showed very steep lapse rates, a long and straight hodograph, high LCLs and a fairly deep mixed layer with relatively low surface dew points. This allowed us to key in on large hail and severe winds being the primary hazards. Additionally, equilibrium levels were only around 9km so hail much larger than 1” was determined to be unlikely.

We issued our first warning upon noticing a rapid uptick in updraft intensity on OCTANE, which showed cooling cloud tops, fast motions, and strong divergence aloft. This storm was located west of Albuquerque in a sparsely populated area so it is difficult to say if the warning verified or not. Gremlin showed a similar uptick in simulated reflectivity which added weight to our decision to warn.

We issued additional warnings as the storm traveled into the Albuquerque area. A second and third cell began to strengthen as well, and two more warnings were issued with the southwest storm looking the most intense on OCTANE. Our mesoanalysis determined that the low-level cumulus field east of the northeastern cell appeared flat and was therefore stable…so weakening was anticipated as it moved off the Raton Mesa.

As expected the northeastern cell began to weaken and dissipate, which was evident on OCTANE and Gremlin. The two cells further southwest continued to look strong, and warnings were maintained into the Albuquerque metro. A hail report of 1” was received at this point on the southern margin of the city.

Lastly, lightningCast showed the northeastern cell begin to weaken before its appearance on satellite degraded significantly. This allowed us to cancel the warning early, in conjunction with noticing the downward trends in OCTANE (weakening cloud top divergence).

During the course of the event we had to keep tabs on a fictitious DSS event, and used LightningCast and its associated dashboard to determine when lightning was approaching their critical threshold (10 miles). LighgtningCast did a good job with lead time as it had 70 percent or higher before any lightning was detected nearby.

– WxAnt

EWP Blog

Spring Experiments & Beyond

Category: DSS