SPG2026 – Page 4

Cloud Top Cooling Signals

Posted in OCTANE Speed Sandwich, SPG2026 on April 28, 2026 by Kevin Thiel.

The Octane Cloud Top Cooling product provided a strong indication of the continued southwestward development of storms in advance. While in the towering cumulus stage of development, the CTC indicated the stronger updrafts. Later on, those towering cumulus continued to develop into mature thunderstorms. While highlighting the areas that ended up growing, I didn’t notice it flagging any of the bubbling cumulus in areas where storms did not develop. This raises my confidence in the product as being able to use it to identify areas of greater concern. It may be worth noting that high level cirrus hid any potential updraft development in the southern portions of the area. However, in this specific case that proved to be non-consequential

Figure 1: OCTANE CONUS cloud top cooling at 18:51 zulu. Cloud top cooling can be seen on the line extending SW from the then dominant supercell.

Figure 2: Radar screenshot from roughly the same time as Figure 1.

Figure 3: The OCTANE CONUS cloud top cooling at 1911 zulu. Showering more development and continued signals on the SW flank.

Figure 4: Radar corresponding with Figure 3. Storms continued to develop and intensify in the same region highlighted 20 minutes prior in Figure 1.

-wxboi

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

Big Ol’ Storms, Amazing Satellite Products!

Posted in Lightning Stoplight, LightningCast, OCTANE Speed Sandwich, SPG2026, Synthetic GXI on April 28, 2026 by Kevin Thiel.

Today’s focus for my group was over WFO FWD where discrete supercells developed, eventually congealing into a more linear storm mode. Being on the DSS desk today, I primarily used lightning products today, though I did peep at a few others. I wanted to take a moment to highlight the GeoXO 5.15/0.91 products for very clearly defining a moisture gradient over northeast TX that would eventually go on to be our focus point for CI.

Figure 1: WV/WVT/Itob/VISob Compare highlighting distinct moist/dry boundary

LightingCast:

Provided DSS using LightningCast V2 overlaid with OCTANE CONUS CTC. I really like using the products together as the increasing LightningCast probs nudge me to either contact or not contact an EM. Overall, I thought the product did very well. I did notice something odd in the dashboard that I spoke with the developer about – instances of GLM flashes were observed at a time there was a downward trend with LightningCast. Figure attached below.

Figure 2: LightningCast V2 vs V1

For documentation, here was the primary procedure I used today to make decisions:

Figure 3: OCTANE CONUS CTC w/ LightningCast (yellow circle is 8-mile radius DSS event)

Using all of the above mentioned products, here was a CWA graphic I put together:

Figure 4: DSS graphic

Feedback for Day 2

LightningCast: For the Dashboard, I feel like V2 did a better job than V1. The amount of variables being measured is a little confusing, and over time, I noticed I was more just looking at a trend rather than all of the different variables.

Stoplight: Though I never got to give the all clear for my DSS event, Stoplight matched up very well with LightningCast and radar trends.

OCTANE: Made some progress in terms of understanding some of the OCTANE products today, thank you for answering all of my questions, Jason! I really liked that we had 2 live weather events to compare the difference in the wind profiles with OCTANE. Yesterday, we observed a lot of greenish hues, indicative of stronger low-level flow. That element was a bit more lacking in FWD today, and the imagery corroborated that with more blue hues. Jason also showed us examples of cloud top divergence, with more blue/green colors indicating deceleration. After getting to know these products a little better today, I feel less overwhelmed by it.

GeoXO: I continue to be very impressed with this product’s moisture and boundary detection. The example I shared above was very impressive and mostly lined up with the 00Z HRRR.

SZA: Did not look at SZA today

-simoom

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

Overview: Week 1, Day 2

Posted in Daily Summaries, SPG2026, SZA Imagery on April 28, 2026 by Kevin Thiel.

10AM

Day 2 of the experiment brought another Moderate Risk region from the SPC, driven by a 30% CIG 2 Hail outlook. Thunderstorms were expected to form along an advancing dry line, with a diffuse temperature and moisture gradient in place from southern Oklahoma to northern Alabama as of 15Z. After our morning debrief, the Fort Worth-Dallas office (FWD) was a pretty easy pick for us to target today. After more discussion, we decided our second WFO should be further east ahead of some early morning convection in the Jackson, MS (JAN) office. Unfortunately the Lightning Stoplight product continued to face ingest issues and was unavailable today, and we hope to have it in AWIPS tomorrow. In the meantime forecasters viewed that data on the SPoRT Lightning Viewer and in GR2Analyst.

1 PM

Forecasters today were tasked with issuing simulated Severe Thunderstorm and Tornado warnings in WarnGen on AWIPS-II, along with providing decision support for mock-events that we created for each office. Today FWD was tasked with mock-DSS for a Red River BBQ Cookoff near Gainesville, TX, and JAN was tasked with mock-DSS for a hazmat spill near Waverly, MS. Shortly after operations began, CI occurred just west of the FWD CWA, and thunderstorms were maturing just west of the JAN CWA. This gave everyone plenty of storms to observe, and the forecasters with the chance to issue warnings and communicate hazards through decision support.

I spent part of the day in ops viewing the SZA imagery product on the west coast shortly after sunrise. When comparing SZA data in a modified Day Cloud Phase Distinction RGB against the traditional RGB, the differences are stark right at sunrise, and features stand out sooner. How much sooner is something we need to determine. There was a nice discussion in the morning about how SZA imagery may benefit WFOs in higher latitudes (main example: Alaska). I also compared the modified SZA RGB against CIRA’s GeoColor imagery, and found that more interesting than anything.

When zooming into the SZA imagery in north Texas, it appears the 0.69µm (channel 2) imagery has ‘gaps’ in highly reflective features. My first hypothesis is that the solar zenith adjustment is pushing reflectance factor values above 130% and creating plotting issues in AWIPS, but I feel like traditional ABI visible imagery saw similar artifacts in AWIPS after launch that had to be corrected.

Kevin

Lightning Cast V1 vs V2

Posted in LightningCast, SPG2026 on April 27, 2026 by Kevin Thiel.

LightningCast version two highlighted an area of towering cumulus as having a greater probability of producing lightning when compared to version one (30% vs 10%). Later on, version one caught up with version two, highlighting the same area, with both versions increasing to 70% (not pictured). However the signal showed up well in version two about 20 minutes ahead of version one.

Figure 1: GOES flash extent density, 1-min lightning plot, cloud phase distinction, and Lightningcast v1 (left)/ lightning cast v2 (right). Valid at 1930 zulu

Figure 2: GOES flash extent density, 1-min lightning plot, cloud phase distinction, and Lightningcast v1 (left)/ lightning cast v2 (right). Valid at 1950 zulu.

-WXboi

Satellite, Satellite, Satellite

Posted in OCTANE Speed Sandwich, SPG2026 on April 27, 2026 by Kevin Thiel.

Warm Sector and no Synoptic Forcing: Paducah Kentucky Edition

We started today with a very established capped warm sector. Dewpoints were in the upper 60s and low 70s across the CWA. MUCAPE values were in the 2000 to 3000 J/kg range with 0-1 km SRH around 250 m^2/s^2. The thermodynamic parameters had started off well, but an early afternoon filled with cumulus clouds may spoil the convective threat. None of the warm sector convection never had gotten a chance to get started, there were glimpses of potential, but would quickly fizzle out. This will change quickly into the evening as the cold front moves across the region, but it is out of the “operational period”.

Vertical Wind Profiles:

With much quieter weather this afternoon than anticipated, we were able to deep dive the various uses of OCTANE. One of those is looking at the vertical wind profile. At the 0-3 km layer there is consistent south-southwest motion, while the 3-6 km layer is moving west-southwest. This analysis allows us to create a sense of ground truth that we are able to compare with models.

Figure: Here in this image we have low clouds that are identified as this more brown color, while the higher clouds are in the green. In motion these clouds have a well defined hook vertical wind profile with the lower layers moving south-southwest and the higher layer moving west-southwest.

Figure: Here is the 22z RAP model hodegraph for the convection southeast of Marion in the previous figure. This paired with the satellite product listed above we are to say with good confidence that in Northwest Kentucky there is a well defined hooking hodograph.

Final Thoughts:

For a day filled with a firehouse of new techniques they all stood out with their uses. The common theme for me is confidence in the models and also the ground truth. Each of the techniques we were shown helped to build confidence in either direction. It will be interesting to see how effective these techniques are, when in a more normal “operations” setting filled with time and workload constraints.

-Blizzard

April 27th Severe Storms – A Satellite Analysis

Posted in OCTANE Speed Sandwich, SPG2026, Synthetic GXI on April 27, 2026 by Kevin Thiel.

A large-scale, multi-state severe weather event is unfolding across the Midwest and Ohio River Valley, extending down into the Mid-South region. With a broad warm sector and CIN dwindling, the first focus was to watch for any discrete cells out ahead of the front that would pose an all-hazards risk. To get an idea of where the best moisture is and where any gradients between dry/moist air exist, I utilized the 4-panel that shows modeled GeoXO data vs GOES-19 imagery. This imagery did a great job highlighting the areas of best moisture and showed a clear distinction in dry vs moist air.

Figure 1: 4-panel layout comparing GeoXO Synthetic data (top) vs GOES-19 obs (bottom)

For monitoring potential discrete CI in WFO PAH’s area today, we utilized the CONUS OCTANE Cloud Top Cooling product with LightningCast ABI+MRMS overlaid. As we watched the cap continue to erode through the afternoon, I noticed “popcorn” like cumulus developing that exhibited rapid vertical motion as detected by the OCTANE satellite imagery. Most of the activity that started to develop, though, quickly fizzled out due to the cold front being so far behind. Still, this was an interesting observation and a utility I find very useful for DSS operations. Outside of our area of interest, we got to watch how rapidly discrete cells developed south of Kansas City, and learned that there is a correlation being studied between how cool a cloud top gets and how instability exists in the environment.

Figure 2: Left Image: 18:32Z, Right Image: 19:22Z

We also learned today that we can analyze low-level winds with the OCTANE Speed/Direction sandwich. For the WFO PAH area, we observed more directional shear with low-level turning of winds. In this instance, I turned off the Speed layer and only had the Direction layer selected. This highlighted the area where low-level shear was greatest.

-simoom

Overview: Week 1, Day 1

Posted in Daily Summaries, Lightning Stoplight, LightningCast, SPG2026, Synthetic GXI, SZA Imagery on April 27, 2026 by Kevin Thiel.

9AM

Welcome to the testbed! Day 1 is usually when forecasters are just getting their feet wet with the products, but today they may get thrown into the deep end. The 13Z SPC Outlook features a Moderate Risk and large Enhanced-Slight Risk through the Mississippi Valley, driven by a 15% CIG2 threat. Forecasters will mostly be getting familiar with products and using AWIPS in cloud instances, but hopefully they will have plenty of good storms to observe today! Unfortunately we’re having issues getting the Lighting Stoplight tool into AWIPS, and it was only available online today.

1PM

We localized to Paducah, KY (PAH) and St. Louis, MO (LSX) with the expectation that semi-discrete thunderstorms would develop during our operations period. Unfortunately thunderstorms took too long to develop for PAH, but there was plenty of thunderstorms to the west across Missouri and north towards Illinois and Indiana.

We observed low level dry air from the Synthetic GXI data from a front and dry line that passed through western Oklahoma. It was interesting to compare the synthetic data from WVT and low(est) level water vapor at 5.15 µm against the observations from GOES-R in the split window difference and visible imagery at 0.64 µm. Some questions for the forecasters included how easy it was to identify features and boundaries in this clear-cut and more strongly forced scenario.

4PM

Later in the day our group also had a discussion about extremely large flashes as detected by GLM and the ground networks, and how (or if) they could be interpreted by products such as LightingCast or the Lighting Stoplight tool. Could LightningCast add lower probability contours? Would those contours add to noise and too many false alarms? How sensitive should users be to the appearance of probabilities?

6PM

To end the day, I saved off some animations of the SZA products. I tried adjust the Day Cloud Phase Distinction RGB recipe when including the Channel 2 and 5 SZA bands, so we will see how forecasters react to that product.