Category: SZA Imagery

Running with SZAs: Lessons to Carry Forward From the Spring 2026 SPG

Posted in OCTANE Speed Sandwich, SPG2026, SZA Imagery on by Kevin Thiel.

Today marks the final testing day of the 2026 Satellite Proving Ground. It has been an illuminating week for myself – a pun we’ll get back to in a second. But first, some serious business. The Satellite HWT has proven to be a beneficial experience for a multitude of reasons. Foremost of those is the opportunity to test and help shape development on a whole new generation of satellite-based forecaster tools. But one shouldn’t discount the benefit that comes from the process, the collaboration, and the chance to work with scientists one might not get to meet otherwise. For me at least, this collaboration has been the most satisfying part of the week. A sincere thanks to the organizers, developers, and other forecasters who have made this week such a treat.

Ok, now back to the pun. This has been an illuminating week testing out five different satellite-based tools. The one tool that I haven’t shared imagery from this week is the SZA azimuth-corrected imagery. There’s a simple reason for that: it is designed to increase the visibility of day-cloud satellite products in low light scenarios around daybreak and dusk. The actual experimental time for this project is from early-to-late afternoon across the CONUS. Not exactly an ideal time.

So with that in mind, one of the first things I did today was to check in on SZA imagery from off the coast this morning. This side-by-side comparison of Day Cloud Phase between SZA and non-corrected imagery shows how powerful of a tool this could be.

Figure 1: SZA-corrected Day Cloud Phase (left) and non-corrected imagery (right) over the Atlantic Ocean early this morning

It’s one thing for Day Cloud Phase to gain more definition in the updraft/anvil pinks right at daybreak. That is valuable, but only so much. We already kind of know what’s happening at that level. The forecaster can benefit so much more from increased brightness right by the surface, where dynamic processes and even the texture of the clouds can help us discern so much.

I spent most of today as the “warning operator” at the Topeka simulated WFO. This meant I wasn’t experimenting with satellite products as much as I was testing how they could be used in warning operations to increase confidence in severe impacts from a thunderstorm. Invariably, my real-life operations rely on Day Cloud Phase as just one of the best products to detect vertical motion trends within convection. There are multiple forms of Day Cloud Phase that one can use within this experiment. I am particularly intrigued by MesoAnywhere’s ability to level the playing field, so to speak, when Mesoscale sectors aren’t available for the GOES satellites. Unfortunately, I did not proof the gif pulled off of AWIPS to try and demonstrate that point, and it is not time-matched between different products.

Figure 2: A gif that I did not realize was going to be frame-unmatched showing the three different types of Day Cloud phase available without a meso sector

The products that we tested this week all have the potential to enhance operations in the NWS. I look forward to reviewing them with my colleagues in the weeks to come.

Sabrina Carpenter

Tags: None

Last Impressions

Posted in Lightning Stoplight, LightningCast, OCTANE Speed Sandwich, SPG2026, Synthetic GXI, SZA Imagery on by Kevin Thiel.

 SZA

Love it! Can’t wait for it to be implemented. The amount of detail that can be ascertained both earlier in the morning and later in the evening is unbelievable. Main applications in my area would be for fog detection and snow squalls. While maybe a bit niche, the snow squall phenomenon is always a challenge. It’s a shallow feature that really ramps up in the afternoon and evening hours. If it’s too far out our radar really can’t pick up on it and the day cloud phase is often one of the best tools for tracking.

OCTANE

Continues to impress! The cloud top cooling tool remains a slam dunk for identifying cells that are quickly growing upscale. The example below shows further cooling after a decent anvil had already developed.

Image below is from the same time above 2112Z

8 minutes later the storm looks to be producing hail

Lightning Cast

Another solid product. I didn’t notice too much difference between the two versions but the parallax fix is very welcome. I personally won’t use the dashboards as I like to see the data overlaid with satellite and radar. Just seeing a chart with numbers moving doesn’t work for me. However, if I would recommend adding a sound feature to the dashboard. The only other suggestion I have is using less contours. I prefer the 10, 25, 50, 75 that are already in AWIPS.

Lightning Stoplight

First time ever using this tool but it will definitely become a mainstay in my arsenal for helping with DSS. I really don’t have a lot of feedback to give. The tool is simple and easy to use. I like overlaying radar on top of it in my procedures and I’m neutral to the idea of changing green to blue.

Geoxo products

These were neat to look at over Africa and Europe, but I found myself really struggling to use them stateside. I may need more training to fully understand the benefits of the synthetic satellite data, but I can’t see myself using it. I already have a ton of different CAMs I can look at, so I’m not sure I understand the benefit of looking at the synthetic satellite. I do have high hopes for the WVT tool though. The color table is very difficult for me to tease out what I need from it though. I tried manipulating the ranges a few times and also changed dry to brown and moist to green, but it still seems pretty difficult to pick out features for myself. What I really want is something to help me track boundaries. Jason shared a really neat animation over Africa that highlighted boundaries very neatly, would love to see if that could be implemented somehow. My end goal is I want to see moisture boundaries from lake breezes, decayed thunderstorms, or different moisture fields such as evapotranspiration

IsthataTOR

Tags: None

Overview: Week 3, Day 4

Posted in Daily Summaries, SPG2026, Synthetic GXI, SZA Imagery on by Kevin Thiel.

The final operations day of the testbed began with our last daily debrief session, and we talked a bit about the applications sounding information with respect to the future GeoXO mission. The forecast for today was…meh? We had storms in the forecast, but the environment during our operations was marginal for severe weather overall. One office was localized to Billings, MT (BYZ) to capture developing thunderstorms closer to the jet streak, while a second office was localized to Topeka, KS (TOP) close to a remnant MCV that was kicking off convection already by 16 Z. Both offices got two mock-DSS events again today. If thunderstorms were looking unlikely to form in the Billings CWA by ~20Z we planned to move them to the Miami, FL office. Thank you Florida for being our safety net for thunderstorms.

Two MDs were issued by SPC during the afternoon for our forecast areas, with one resulting in a severe thunderstorm watch.

 

 

With Jonny’s help I made a ‘test RGB’ from the Synthetic GXI imagery. There’s no physical basis to the RGB (yet!), but it was a proof of concept that we could do it. An example and the recipe is shown below. What features can we pull from this new imagery relative to water vapor at low levels and through the entire column? Maybe we can figure it out in future testbeds!

 

 

During operations, I showed forecasters another example of SZA imagery over California with the impacts of the marine layer with low clouds and fog. Forecasters also compared this imagery against the Nighttime Microphysics to see how long the ‘gap’ was between the two, and what features you could identify with each product. Additionally I found a case from a fire from sunrise through the lens of the Day Fire RGB.

 

Kevin

Tags: None

LTG DSS with LTG Cast and Stoplight

Posted in Lightning Stoplight, LightningCast, SPG2026, SZA Imagery on by Kevin Thiel.

Upon starting the shift we had a supercell that was about 1 hr out from our first event. In operations our DSS forecaster would have immediately informed our partner that the cell (which had 1” hail report) is barreling in from the southwest.

Both versions of the LTG cast were providing a 70% chance of LTG within the next hour as well, with convection out ahead of the main supercell the heads up notification would also have included this information.

45minutes later we had our first lightning strike onsite ahead of the main supercell.

——————————————————————————————————————————

Activity began to wind down by 2030Z

An all clear call would have been made at 2100Z with the stoplight product largely vacant of any lightning detection. MRMS-10C was also outside of the 8mile range ring with little build up expected upstream. Lightning cast had also dropped to around 10%.

IsthataTOR

Tags: None

Overview: Week 3, Day 3

Posted in Daily Summaries, Lightning Stoplight, LightningCast, OCTANE Speed Sandwich, SPG2026, Synthetic GXI, SZA Imagery on by Kevin Thiel.

Day 3 started with our debrief from Tuesday, along with a focus group activity for GeoXO lightning mapper capabilities. I showed forecasters SZA imagery near sunrise during a period of glare from the GOES-East perspective near sunset. Overall forecasters felt the cloud tops were more ‘washed out’ by the brighter visible channels, but mentioned the important feature from the Day Cloud Phase Distinction is often the cloud phase before the overspreading anvil cloud begins.

Traditional Day Cloud Phase Distinction RGB

SZA Day Cloud Phase Distinction RGB

Wednesday targeted the Northern Plains again, with the cold front being are only source of lift and deep layer shear that we can pull from this week. We decided to localize the forecasters to NWS Grand Forks, ND (FGF) and Aberdeen, SD (ABR), and each had two DSS events so they could leverage the LightningCast SuperDashboards.

1PM

Storms were slow to develop early in the forecaster period with a bit of cloud cover making the Synthetic GXI imagery less usable, so the product developers took both offices on a ‘tour of Europe’ showing off the Water Vapor Transmittance product from the Meteosat-12 FCI. This led us back to the states where we talked more about colormaps for WVT and what forecasters preferred. I made a display as part of that discussion. Upper left is WVT with ‘flipped’ colormap, upper right is WVT with the origional colormap, lower left is WVT with a red-green colormap made by a forecaster in the previous week, and the lower right is PWATs from the most recent HRRR run (18Z).

2 PM

Forecasters in both offices focused mostly on DSS tasks early in the forecast period, along with comparing OCTANE’s CONUS and MESO products. Additional discussion centered around the Lightning Stoplight tool and debating the ‘optimal’ color table to convey the intended actions from those viewing the product.
As thunderstorms approached the mock-IDSS events forecasters interrogated LightningCast data and discussed its applications, along with the desire to have variable ranges for the dashboard web display. We did run into an interesting case where a thunderstorm initiated over a narrow band of cirrus clouds, which may have impacted signals from OCTANE and LightningCast.

To end the day, I spammed AWIPS looking for sunrise imagery to show off SZA (thanks Justin for turning on the feed so early!)

Fog and low clouds from the marine layer along the California coast from the Day Cloud Phase Distinction RGB (SZA left/traditional right)

Valley fog over the Appalachian Mountains in the morning from the Day Snow Fog RGB (SZA left/traditional right).

Kevin
Tags: None

Overview: Week 3, Day 2

Posted in Daily Summaries, LightningCast, SPG2026, SZA Imagery on by Kevin Thiel.

10 AM

Tuesday began with our morning discussion from Monday’s operation/orientation day. Forecasters had plenty of storms to observe yesterday, which allowed everyone to get acquainted with OCTANE. Forecasters talked about the applications of OCTANE data, and one said it can be a ‘super tool’ for mesoanalysis but also needs ‘super users’. For the Synthetic GXI WVT product, forecasters also showed early support for the ‘flipped’ color table but wanted to see it in action more this week before deciding. First impressions of the Lightning Stoplight and SZA Imagery were also positive, with forecasters finding the Stoplight tool easy to understand and message to partners.

I showed an example of some SZA imagery on CIRA-SLIDER from this morning of river valley fog in the Northeast US. When comparing with traditional imagery and the Nighttime Microphysics RGB, forecasters reacted positively to the ‘brighter’ SZA imagery and expressed the difficulties of transitioning from day to night when observing fog from their respective home CWAs.

SZA Day Cloud Phase Distinction RGB

 

Regular Day Cloud Phase Distinction RGB

Nighttime Microphysics RGB

After talking about the GeoXO GXI in our focus group, our forecast discussion for the day sent us back to the Cheyenne, WY (CYS) and Rapid City, SD (UNR) NWS offices to monitor developing storms along a cold front. Forecasters were also assigned mock-IDSS events in Fort Laramie, WY and Sturgis, SD.

1 PM

Similar to Monday, shortly after operations began SPC issued an MD for our area followed by a Severe Thunderstorm Watch.

 

In the CYS office (still without a radar), discussion focused on their mock-IDSS event and the timing of lightning activity within the event’s range ring. With thunderstorms developing upstream of the site, timing dominated the conversation and the forecasters talked about how the LightningCast dashboard helped identify trends, especially if the partner needed more time to execute their safety plans.

The forecasters also looked at OCTANE, and noted that the the MESO Cloud-Top Cooling products showed a decreasing intensity trend while the CONUS CTC product appeared relatively steady.

3PM

The UNR office frequently viewed OCTANE products today, with several severe thunderstorm warnings issued today. Their mock-IDSS site appeared to ‘miss’ the storms today, but we’ll see what they say tomorrow!

I plan to show this to the forecasters tomorrow to get their thoughts. Sorry for spamming the blog with SZA imagery.

-Kevin

Tags: None

Overview: Week 3, Day 1

Posted in Daily Summaries, LightningCast, SPG2026, Synthetic GXI, SZA Imagery on by Kevin Thiel.

Week 3 kicks off today and the ridge that stymied us in week two is….still there! Thankfully we’ve recovered a good bit of moisture across the plains and southeast for convection to work with. We began today with product introductions and an orientation session, followed by our forecast discussion to decide where we would target today. The forecast was pretty clean cut, with two options of elevated convection in NE Colorado/SE Wyoming and additional convection from a remnant MCS across Mississippi/Arkansas. Based on timing of CI, instability in the high plains, and the size of the MesoAnywhere domain, we decided to localized to the NWS offices of Cheyenne, WY (CYS) and Boulder, CO (BOU).

 

1 PM
SPC issued an MD just before operations began for our area, citing thunderstorm development and a high chance for a watch to be issued later. And by 2pm we had a watch!

In the CYS office, forecasters looked at synthetic GXI imagery and identifying the moisture advection northward into their CWA later in the forecast period. This also led to the discovery that a few of the procedures had ‘inverted’ color maps for WVT. While not intended, we did compare how they looked from each color map. Which is better? You decide!

Original colormap. Dry air/clouds are white, moisture is dark.

‘Flipped’ color map. Dry air/clouds are black, moisture is light.

First impressions of SZA from this morning’s imagery was positive with forecasters in both the CYS and BOU offices. A forecaster with experience in AK said they regularly adjust brightness of visible imagery on the fly, especially in lower light seasons. A forecaster with more experience in the central plains said they rarely adjust the brightness. Some of the areas we examined included over Colorado and Montana. Forecasters mentioned using the DCPD RGB frequently, and having more time with that imagery would be welcome. Additionally, one mentioned liking that the colors stayed more consistent throughout the day.

Forecasters in the CYS office compared LightningCast v1 and v2 from GOES-East and GOES-West along with the timing of the first lightning flash. V2 introduced more heterogenety in the bands, while V1 appeared fairly uniofrm and more widespread. Also LightningCast v2 seemed to be ahead of v1 for thunderstorm growth over the Denver metro.

3 PM
Both offices issued severe thunderstorm warnings for severe wind and hail hazards. Looking ahead, we have a steady stream of SLGTs this week, so we should stay fairly active. Also wanted to noted the CYS radar was out today, so some questions about using Sat data (especially things like OCTANE) for warnings are of interest for the morning discussion tomorrow.
-Kevin
Tags: None

Overview: Week 2, Day 4

Posted in Daily Summaries, SPG2026, Synthetic GXI, SZA Imagery on by Kevin Thiel.

10AM

Thursday began with another group discussion, focusing on the following topics:

  • When to give the ‘all clear’ using the Lightning Stoplight tool
  • The limitations of satellite imagery and OCTANE-CONUS products on days with lots of convective anvil debris overtop developing convection, obscuring signals of stronger updrafts.
  • Playing with the color bars for the WVT product and finding what ‘works’ for showing different moisture boundaries like dry lines and sea breezes.
We played another round of ‘When does the satellite imagery become useful/useless?’ with the SZA imagery. This time we viewed a sunrise over the Mid-Atlantic with the 0.64 µm (ABI Channel 2) visible band, and forecasters stated when the imagery became useful. Here’s the results…
  • SZA Imagery: 0956 Z (x3), 1006 Z
  • Traditional Imagery: 1026 Z (x4)
SZA Imagery

Traditional Imagery

After a full week of MRGL and SLGT events, we were rewarded with…another SLGT! Surface moisture and instability was difficult to come by over nearly the full CONUS, and we relied on moisture transport from the Pacific front and sub tropical jet. Oddly enough this was positioned behind the dry line, which led to some large inverted-V forecast soundings and downburst potential from elevated thunderstorms. The 1630Z SPC convective outlook had a Slight Risk in the Central and Southern Plains, driven by a 15% CIG1 risk in SW KS and the TX panhandle. We decided to localize to the Goodland, KS (GLD) and Dodge City, KS (DDC) NWS offices today (Note: Later GLD office moved to Amarillo).

1 PM

Early on forecasters sent DSS messages to their mock events and waited for convection to develop. In the GLD office some convection tried to form in far-eastern CO, but dissipated and was unable to sustain itself. OCTANE-CONUS CTC showed low cooling values (<10C) and LightningCast was showing lower probabilities. Conversation moved to the Synthetic GXI imagery, and observing the moisture from the mid-level jet across the Southern and Central Plains. The group compared the 5.15µm Synthetic GXI band with the ABI 7.34 µm (Channel 10) IR band designed for ‘Low Level’ water vapor.

3PM

Decided to move the GLD office to Amarillo (AMA) after observing minimal instability in their CWA, and a more agitated cu field on the western edge of the AMA CWA. SPC also issued an MD and subsequent severe thunderstorm watch for the DDC and AMA forecast areas, which reinforced our thinking that convection would be focused further south during our forecast period.
4PM
After some discussion with the DDC forecasters and some developers, we made vis-IR sandwich procedure that mimicked the ‘oops all Day Cloud Phase Distinction RGB’ procedure. The motivation was that once convection gets going, forecaster may liked to transition away from the DCPD RGB and to imagery with more direct visible and infrared information.

5PM

At the very end of the day, we talked about the SZA imagery some more and its applications for OCONUS users in places like Alaska. While roaming the CONUS comparing SZA and traditional imagery, a developer pointed out a large blowing dust event in ND, which was evident even in the DCPD RGB, along with the Channel-2 visible imagery.

That’s a wrap for week 2!

-Kevin
Tags: None

Overview: Week 2, Day 3

Posted in Daily Summaries, OCTANE Speed Sandwich, SPG2026, Synthetic GXI, SZA Imagery on by Kevin Thiel.

10 AM

Wednesday presented a ‘7-10 split’ of severe potential, with thunderstorms expected in the Great Basin and Mid-Atlantic regions. Most of this was driven by a Slight Risk from the 13 Z SPC Convective outlook, driven by 15% CIG1 wind probabilities. Timing and moisture were a little less certain out west, while convection was more certain in the east but had limited deep instability and subsequent severe weather potential. After some discussion, we localized to the Pittsburgh, PA (PBZ) and Pocatello, ID (PIH) offices.

During the morning discussion we played the same comparison game between the SZA and traditional imagery, but this time for the upper great lakes region around sunset on Tuesday, using archived imagery from CIRA-SLIDER. Forecasters were asked when the imagery no longer became useful to them, and here’s their reported times when looking at the same loop between 21 Z and 02 Z.

  • Traditional: 2156 Z, 0001 Z, 0001 Z, 0021 Z
  • SZA: 0111 Z, 0111 Z, 0111 Z, 0111 Z

Here’s the loops so you can play along at home! (Sorry these are really big GIFs, the blog didn’t like the when I converted them to MP4 format)

Traditional Day Cloud Phase Distinction RGB

SZZ Day Cloud Phase Distinction RGB

1 PM

Forecasters in the PBZ office were thrown into a situation where convection was already developing in the western side of their CWA, and they began issuing warnings, investigating OCTANE, and sending DSS messages to their mock-events.

In the PIH office storms were slow to get going, so we looked at some imagery from the FCI and the synthetic GXI imagery from the HRRR. One target we casually watched throughout the day was a dry line in the TX panhandle, and we compared them to moisture boundaries in Europe and north Africa.

3 PM

PIH was issuing warnings by this time, and frequently relied on radar imagery and knowledge of the environment when making warning decisions. When looking at the OCTANE CTC product and other satellite imagery, the presentation of most storms were not impressive.
In the PBZ office, the forecasters noted that the OCTANE CTC product was limited in its application due to dense cirrus and anvil debris obscuring cooling signals in the ABI infrared bands. In the OCTANE Speed Sandwich however, the forecasters found the speed values and textures from visible imagery easier to view new and intensifying updrafts. This resulted in some discussion about how to ‘train’ for this.

By the end of the day, a number of severe wind reports appeared across the PIH CWA from their mesonet, while in PBZ a single hail report was featured. More reports may come in tonight or tomorrow?

-Kevin

Tags: None

DSS: Max Road Fire

Posted in DSS, Lightning Stoplight, LightningCast, SPG2026, SZA Imagery on 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

Tags: None