Last Impressions

 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

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

 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

When A “Bolt From the Blue” Shatters Your Confidence

 Today presented one of those moments where you feel pretty confident in your messaging, but then mother nature throws you for a loop. For the Red, White, and Lavender festival, a line of general thunderstorms was moving over the festival right around start time of our forecast period so this gave me an opportunity to test the Stoplight tool and LightningCast in a messaging scenario for lightning cessation.

What seemed like a pretty straightforward case of DSS messaging to festival goers regarding the line moving east and lightning threat ending turned into a stressful situation for me. At roughly 1935Z, LightningCast showed probabilities were trending downward while the Stoplight tool was also trending toward yellow and green to suggest we would be approaching that “all clear” state. See the LightningCast dashboard graphic below with the main decision timeframe boxed in yellow. So, I confidently messaged my Festival Coordinator an estimated all clear time to be the top of the hour.

Figure 1 . LightningCast Dashboard over Manhattan Regional Airport, near the Red White and Lavender Festival depicting lightning probabilities trending downwards during my DSS decision timeframe.

But then at ~1955Z, the Stoplight tool turned red again WEST of my site (while the Festival itself was under green) as the FED picked up on what I'm guessing were anvil crawlers. I was surprised because the anvil looked pretty thin to me over that area so I honestly didn't know what to think. Then, ENTLN lightning plot showed a number of cloud flashes within 10mi east of the site and eventually plotted a negative CG barely 6miles to the east of the festival at 2015Z (see Figure 2). Talk about shattering a DSS forecaster’s confidence!  It seemed to be one of those “bolt out of the blue” strokes, too close for comfort! To LightningCast’s credit, probabilities never went below 20%, with V1 even hovering around 40% the entire decision timeframe.  Mother Nature sure taught me yet another lesson in humility that one cannot be too confident no matter what!

Figure 2. The Stoplight Tool plotted with FED, ENTLN and DSS range rings at 2015Z. The black arrow denotes the location of the negative CG about 6mi east of the site.

I'd like to think that in a real scenario, I would have been a little more conservative in estimating a time of all clear. But with this being an experiment, I felt a little more bold in just "going for it".

Figure 3. A longer loop of the Stoplight Tool, ENTLN and FED products, including the decision timeframe and point of confidence ruined.

And just for fun, because I’m hooked, below is a loop of the CONUS OCTANE CTC, Speed and Direction products for a rapidly intensifying storm over Cloud and Clay Counties.  Although not as seamless as the mesoscale versions of these tools, there is still a lot of utility in diagnosing storm development and strength with CONUS vs traditional satellite imagery. I’m even becoming more and more a fan of the “blues” colorscale for the CTC product (left hand panel) when plotted on the Ch 13 product. The stark contrast between the dark blues/purples against the rainbow of the IR anvil really catch the eye.

Figure 4 . ECONUS Octane CTC product (left), Octane Speed (middle), and Octane Direction (right).

Astrophage

Cloud Top Cooling Advanced Warning

 Widespread thunderstorms and several supercells were visible moving east-northeast over Kansas this afternoon. The GOES-19 EMESO-1 Cloud Top Cooling showed several large bursts of cooling as visible in two separate supercells in the image below. The northern one showed a tight circulation and a possible brief tornado roughly 9 minutes after the initial burst of cooling. The southern cooling burst strengthened the outflow burst and produced damaging winds that also showed on radar 9 minutes later. A supercell to the west of the region in the image also showed major cooling about 5 minutes before radar indicated a possible tornado and a warning was put out. Based on these few observations, it seems reasonable that severe thunderstorm warnings could be put out long before radar confirmation based on significant cloud top coolings, at least in mature thunderstorms where conditions are favorable for severe weather. In areas where radar is not accessible, this could also be used to help assist in putting out tornado warnings.  

Figure 1: On left: GOES-19 Octane Meso Anywhere CH-13-10.35um and CH-02-0.64um with GOES-19 EMESO-1 Cloud Top Cooling overlaid. On right: Ktwx 0.5 velocity (kts).

It is also worth noting the displacement of the cloud top cooling vs the radar signature due to parallax. Figure 2 shows that this area has a parallax of roughly 19 km to the northwest which would be very important to keep in mind when putting out warnings for any area based on satellite imagery.

Cloudius

Every Cloud Has a Silver Lining - Satellite-Based Mesoanalysis

Satellite-based observations have become a larger part of an operational forecaster’s toolshed with each passing decade. Over the past 10 or so years since the launch of the GOES satellites over North America, forecasters now have access to extremely high-resolution, high-quality data. That data can be used for a wide array of potential benefits, and this satellite HWT is designed in large part to show us how we can widen out that repertoire even more.

With that in mind, I’d like to start out this Hump Day blog post by discussing one of the products that has not been featured as prominently in my previous blogs - GXI water vapor data. In essence, the next generation of weather satellites (GEO-XO) will have the kind of sensitivity that lets us really drill down into the absorption bands to see some neat stuff. That kind of capability won’t arrive until the 2030s, so for this week we are taking a look at what the data could look like via HRRR simulated satellite data.

Figure 1: WVT Ratio from the HRRR (left) compared to Split Window Moisture on GOES-East (right).

As you can see above, there are limitations to this analysis. For one thing, even perfectly initialized models are going to struggle to carry cloud cover forward given its sensitivity. And for another, models are not going to perfectly initialize.

Still, if you squint and look across the eastern portions of NWS Aberdeen's CWA, there is an area of somewhat lighter grey feeding into the cloud band on the HRRR. This is suggestive of a potential moist pool in the region. Actual observations of this would help forecasters dominate the mesoanalysis space like never before.

Perhaps one of the most powerful uses of mesoanalysis tools came from the OCTANE speed-direction tools today. I have spoken at length about those tools, so won’t spend too much time on them. This gif just does a great job of summarizing what we might be able to do:

Figure 2: OCTANE Speed (top left), Direction (top right), Cloud Top Cooling (bottom left), and Day Cloud Phase (bottom right)

Here we have a storm on the north end of the cluster (yellow OCTANE speed, purple OCTANE cloud tops) and developing updrafts to its south-southwest. Those updrafts are occurring in an area of boundary-layer cumulus (shown well by their northeast or yellow motion in the Direction panel). Further to the east, there are clouds oriented along two axes: an area of HCRS (red in the Direction tool), and an area of stable billow clouds (yellow in the Direction tool). Knowing your mesoanalysis, this provides a tell that the northern updraft is likely to wither as it enters a stable boundary layer, which it did. It’s also a tell that further south, updrafts won’t have the same issue. As of the time of this writing, a supercell has developed out of that southern cluster.

This author would be remiss if they didn’t mention the in-person IDSS potential offered by the Lightning Stoplight tool. This has also been discussed previously, so I won’t belabor the details too much. But the ability to display a dashboard from your browser with basically a color-coded area showing how long it has been since the last lightning strike will go a long way toward helping partners understand when DSS activities may restart.

Figure 3: Lightning Stoplight in its web-browser-based glory.

Sabrina Carpenter

FGF CTC CTD Testing

Today's DSS event brought us to the wonderful state of North Dakota in the FGF CWA. Unfortunately with no lightning at either DSS event today, I did not get to use the GOES Stoplight product, so I used Octane again. I continue to be highly impressed by the utility of the OCTANE products. You know the saying “A picture is worth a thousand words”? Well, to me, that is exactly what the cloud top cooling and divergence product embodies. There are so many features that can be picked out from this. Near the bottom left, there are multiple updraft attempts that try but most fail. It shows multiple storms developing in McPherson and Dickey Counties with cooling cloud tops and increasing cloud top divergence. Further to the west in Emmons county it shows a cloud top cooling signal but it ends up disappearing and subsequently the cloud top divergence decreases. Pairing all of the imagery with a visible band really gives some nice textures to the picture where you can easily point out quickly developing features. I find myself continually migrating back to the Octane products for situational awareness as storms approach the DSS event.

Figure 1: East Meso1 Cloud Top Cooling and Cloud Top Divergence with ENTLN lightning data overlaid.

Dry Thunderstorms

Overview: Week 3, Day 3

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

Octane CONUS vs MESO

 I focused pretty closely on the comparison of the CONUS Octane Speed vs the Meso Octane Speed product.

Overall I found that the CONUS product was a bit too coarse to really pick up on the main features of interest.

CONUS 

MESO

The example above really highlights the yellow and dark blue hues making it easier to ID the rapid changing environment as opposed to the CONUS which you can kind of see with the green. But you completely miss the dark blue speed minima found in the MESO

Couple more examples below showing the stark difference between the two.

IsthataTOR

The Think Pony Club: Providing Decision Support Using New-Age Satellite Products

 Picture this: you’re out on the open prairie of Wyoming. The wind is whistling through the grass. The late-afternoon sun shines against the towering clouds that have made the Great Plains famous. Spread out in front of you along the hallowed and historic grounds of Fort Laramie, dozens of people wait in folding lawn chairs. There are picnics and music and the shouts of children playing in the warm June evening. Finally, as the sun starts to set, a shape appears along the horizon. Soon, everyone is pointing and squinting as the figure - a man on horseback - comes galloping onto the fort’s parade ground. Slung over his shoulder is a large bag full to the brim with letters.

It is 2026, and the Pony Express rides once again.

For this romantic and nostalgic scene to take place, the patrons of the event need to be kept safe from any sort of adverse weather. Fort Laramie is tremendously exposed to frequent summertime convection, and the National Park Service requested DSS for the great ride this evening. With good reason: by the time shift change occurred at noon MDT, storms were already beginning to develop along the Laramie Range 50 miles to the southwest.

This turned out to be a fascinating case throughout the afternoon - a real “will it or won’t it” as thunderstorms developed and pulsed multiple times over that 50 mile range. The forecasters at Simulated WFO Cheyenne noted increasing lightning potential as early as 1:30 MDT with a much stronger updraft moving off of the terrain. It was initially thought that by 2:30-3:30 MDT, the Fort Laramie area would likely see lightning. However, the storm weakened - a process captured much better by OCTANE Cloud Tops on the Meso band than the CONUS sector.

Figure 1a: Cloud tops from OCTANE over the CONUS sector, showing deepening purples in far southwest Platte County associated with the storm moving toward Fort Laramie.

Figure 1b: Cloud tops from OCTANE over the Mesoscale sector, showing a decrease in the area of purples as the primary thunderstorm collapsed.

Eventually, convection did begin to approach the DSS location. Using a 15-mile range ring, it was unclear whether or not we would breach the event trigger. Two storms developed west of Fort Laramie by about 30 miles and were moving east. The southern storm would undoubtedly track through that 15-mile range ring, but it decayed before arriving. The storm’s final cloud flash occurred about 17 miles away from Fort Laramie proper.

The bigger question, of course, was the updraft on the northwestern flank. If it followed an easterly track, then lightning would assuredly get into the 15-mile range ring. However, a complicated storm splitting process occurred, and regional radar observations (primarily Rapid City radar, scanning at 20,000 feet - the Cheyenne radar is out of commission) suggested that the left split took most of the updraft mass due northward with it. This led to a fascinating case study for LightningCast, where the two MRMS-based V2 products predicted much lower lightning probabilities than the V1 purely satellite-based products, likely due to obfuscation of updraft movement under all of the anvils.

Figure 2: GOES-East (left) and GOES-West (right) LightningCast probabilities at Fort Laramie using the legacy (red) method and the MRMS-included (green) method.

Something to really keep an eye out for when using LightningCast in future IDSS deployments: depending on which product you hitched your wagon to, you could have predicted lightning probabilities of anywhere between 20 and 75% simultaneously. Be careful to use the best data available and blend when possible!

The storms did eventually decay and move off to the north, leaving our hypothetical crowd with a lovely afternoon to enjoy some classic prairie fare, and to prepare for the noble steeds of the Pony Express to ride again.

Sabrina Carpenter

Applications of OCTANE in Disorganized Convection

 
I had the privilege of serving as the initial warning operator for WFO Rapid City as we began operations during ongoing convection over the Black Hills. This activity remained very junky and disorganized throughout the morning, as evident on various satellite imagery and radar. I found OCTANE products to be very useful as a situational awareness tool throughout the day, and it also showed to be a great indicator of when the convection began to transition from junk to slightly more organized severe.

There were signals in the CONUS CTC product that more vigorous convection was beginning to develop underneath the broader anvil (not shown). Then the combined CONUS/mesoscale tracking, speed and direction products highlighted the transition to more intense convection starting roughly with the 1941Z image in the loop below. Increasing speeds at anvil top (yellow color) followed by the appearance of a strengthening color gradient from light blue to yellow denoted the transition in storm intensity. This prompted me to begin finer scale interrogation on radar for severe warnings. I issued the first severe thunderstorm warning at 2004Z for large hail and damaging wind potential, feeling pretty confident that these storms were tapping into a lot of available instability after observing the evolution of cloud top signatures.

Figure 1.  OCTANE Mesoscale Speed Product merged with CONUS Tracker Imagery 1857-2017Z.

As the event unfolded, I was pleasantly surprised at how helpful the CTC product was in highlighting additional intensifying storms underneath the ever-expanding anvil. The “stop light colors” of the CTC product contrasted nicely amongst the cooler Ch-13 colorscale as seen in the loop below, really catching the eye for which storms as viewed on radar should be further interrogated next. I can see this being a very valuable tool in warning operations, especially as mesoanalyst but warning meteorologist too.

Figure 2.  OCTANE Cloud Top Cooling (CTC) Speed Product merged with CONUS Tracker Imagery 2026-2146Z

Astrophage

Severe Thunderstorm Divergence

 Multiple severe warned supercells were visible today over southwest South Dakota. These were producing impressive updrafts as indicated by the green cooling cloud tops in the overshooting tops of the anvils. The direction of the cloud top flow in the anvils is clearly split along the line of development with both the speed, cooling cloud tops, and divergence providing a defined location for the center of each supercell. This location is particularly evident in the cooling cloud tops which provided a lead time of 5 to 15 minutes ahead of the divergence and potentially a couple of minutes before the strengthening of the radar reflectivity signal. I was also surprised by how much of a difference the parallax makes in this region. Overlaying these satellite images with radar, there was a noticeable difference in location of the supercells. This was visible in both the GOES-18 and GOES-19 images, with an offset of roughly 10 miles to the northeast and northwest respectively. With such a large gap, I am curious if this was accounted for when issuing severe thunderstorm and especially tornado warnings for the Cheyenne region that had little radar to go off of.

Figure 1: GOES-18 WMESO Octane speed, direction, cloud top divergence, and cloud top cooling.

Cloudius

Initial Impressions

 

Very impressed with the Octane CTC product. This loop is probably a bit too fast. But It captured and area of rapid cooling east of Perry Park

At that time radar was not picking up on much at all.

20 minutes later the cell really took off with a deep core of over 60dbz reaching above -20C (panel in the top right)

While the storm was pretty vertically stacked there low ZDR and lack of melting near the surface likely lead to hail production. The fact that the CTC ID’d the area before any signal on the radar is very impressive.

The other thing that caught my eye today was the WVT Ratio. After playing around with the color map ranges I was able to tease out the moisture feed streaming into the Front Range. Overlaying this with observations matches the overall surface streamlines well. Would be very interested to see this in a dry line set up.

IsthataTOR

BOU Octane Cloud Top Cooling Observations

Day 1: GOES-19 CONUS Octane Cloud Top Cooling proved itself to be a very helpful tool for diagnosing deep CI attempts along the front range of the Colorado Rockies. It was interesting to see several failed attempts at CI when the colors turned from green back to cyan. I found it to be an excellent RGB for situational awareness in the pre-storm environment. It was nice to quickly diagnose updraft strength as well. Pairing it with the 5 minute CG Flash ENTLN 1 minute update lightning plot helped me quickly visualize the parallax effect on GOES-19 where you have to mentally adjust where the actual storm to the southeast. Using just those 2 datasets alone, I tried to draw a couple of severe thunderstorm warnings. The boxes were most likely bigger than what was actually issued since I was playing it safe including most of the lightning within the back end of the box. I liked how the CTC product did not show any colors above 0C to tease out surface level features. It looks like there was some sort of mesoscale boundary that moved into the southern part of the Denver metro that led to additional CI. I would not have picked out that boundary as easily if the CTC product had colors through 30C for example.

Figure 1: Convection initiation and intensification over the Denver metropolitan area using GOES 19 ECONUS Octane Cloud Top Cooling imagery.

WXMANDAN

A High-OCTANE Way to Start the HWT

 The first day of our Satellite HWT threw us up against the ultimate satellite forecasting challenge - how to analyze severe convection while the local radar is out of service. Specifically, KCYS is out of commission this afternoon while convection is developing off of the Laramie Range.

This presents an interesting challenge for the newest version of LightningCast. LightningCast V1 is a purely satellite-based product that uses four different satellite channels to determine the likelihood of an updraft producing lightning in the next 60 minutes. We’re here this week in part to test Version 2, which uses those same methods but is also trained on several years worth of MRMS isothermal reflectivity at the -10C level. Here’s the issue, though: if KCYS is out of commission, then the closest radar (KFTG) is shooting at 21,000 feet for the 0.5 degree reflectivity scan over Wheatland, Wyoming!

With that in mind, here’s the legacy LightningCast (left panel) vs LightningCast V2 (right panel) as an updraft developed off of the Laramie Range today.

Figure 1: LightningCast probabilities valid at 18:16 UTC on June 1, 2026

Notably, the first lightning strikes came in about 15-20 minutes after the above screenshot. The MRMS-based LightningCast was, if anything, a little more conservative than its no-radar ancestor. It also was struggling to display any reflectivity. You never want to infer a causal relationship based off of one case, but it wouldn’t surprise me if the two are connected.

In another exciting introduction to satellite-based mesoanalysis tools, we got a good look at OCTANE speed/direction tools, which allow us to directly measure the motion of cloud layers that may not be accessible to satellite (eg, the anvil). Below, we are looking at a cluster of severe thunderstorms near Chugwater, Wyoming.

Figure 2: OCTANE Direction product on June 1, 2026

The sharp gradient in greens and oranges is suggestive of divergence within the thunderstorm anvil region - which we would expect to see in an updraft that is evacuating mass toward the tropopause. Even more interestingly, one can see the arced band of inflow clouds/HCRs extending well back into western Nebraska, not just as they feed into the storms, but also as they are literally bent inward by the pressure perturbations. The red hues to the feeder clouds in Nebraska is suggestive of a motion from the southeast, while closer to Chugwater those feeder clouds moved more from the south. We thus know that the thunderstorms are exhibiting a mesoscale influence on their environment.

-Sabrina Carpenter

Rapid cooling visible with developing supercells.

 Scattered to widespread severe thunderstorms were shown to be developing from Fort Collins south and through the Denver metropolitan area. When overlaid with other products, I noticed how LightningCast v2 was able to catch on to some of these rapidly cooling cloud tops faster than v1. The contrast of the strong convection vs weak was very helpful in determining which cells were going to become severe or not as well as which mature supercells were maintaining strength or weakening.

Fig 1. Rapidly cooling cloud tops and several mature supercells shown developing across the Denver metro.

Cloudius

SPG Blog Post Day 4

Today’s Set-up: Strong low pressure system moves through the region, with associated cold front. Slight risk over northern Texas, Oklahoma panhandle, and western Kansas. I was simulating the Dodge City office today. Their primary threats were severe wind gusts from an incredibly deep inverted V sounding, and some possible small hail.

Figure 1: LightningCast Viewer  

• Got more experience with the LightningCast dashboards. I got the events pulled up fine, and I found myself pulling the dashboards up to get a quick visual on trends, and which site was more at threat.
• This helps me, as a forecaster, get an idea on which event needs to be notified before the other. AKA - which event is the priority, based on the ongoing weather.
• I explored some of the options that you can overlay on LightningCast viewer
• Having METARs pulled up is VERY helpful for getting some ground truth to what I am looking at on satellite and radar.
• I also appreciated having the SPC outlooks overlaid in the back, to have a quick guide for where is favorable for severe weather.

Figure 2: GXI-ALL Procedure

• On a day like today, with a pretty strong frontal system and dry air in a lot of places, the GXI products worked well at highlighting the moisture ahead of the front. You can pretty clearly see the boundary moving through the CONUS.
• I did not get much help when looking at the CWA level view, but looking at the “big picture” CONUS view was significantly more useful for me in operations today.

Figure 3: CONUS Octane Speed Product

• This image was earlier in the operations period, and I thought it was interesting to see that the speed was all relatively uniform. We’re used to looking for plenty of speed and directional shear in severe weather, but here most systems were moving around 30kts or so.

Figure 4: CONUS OCTANE CTC

• I took a peek at cloud top cooling for some of these storms, and they were very cold (~-55C).
• I saw that the office to the south issued warnings based on that (shoutout!) and I looked into it a bit more, and realized we had even colder cloudtops. After radar analysis and further satellite, along with trying to find some ground truth, I put a warning out for the eastern portion of the CWA.

-Kelvin-Helm

OCTANE Cloud Top Cooling with Shallow Convection

 Convection over the PIH CWA was fairly shallow today due to the limited instability. That being said, strong DCAPE developed, owing to pronounced Inverted-V profiles. The line of storms that developed was able to produce significant wind gusts, with multiple reports of 70 to 80 mph winds.

Satellite products were not particularly helpful in knowing what storms to issue warnings on due to the shallow nature of the convection. The loop below shows visible, IR, and water vapor imagery for the area of interest around the time we issued our first warning.

Figure 1 - Satellite imagery over the PIH forecast area around the time of warning issuance.

The thing that really stands out is that everything looks about the same. No single storm stands out as being particularly tall or possibly severe. The same is true when we look at the OCTANE Cloud Top Cooling product.

Figure 2 - Cloud Top Cooling around the time of warning issuance.

There was never a value of more than 3°C per 5 minutes over any of the developing convection, indicating the weak instability present. This doesn’t help much in figuring out what storms we need to focus on.

So we turned to radar. The KSFX radar showed an area of 50 knots inbounds associated with an area of higher reflectivity. This led to us issuing the first severe thunderstorm warning of the day.

Figure 3 - KSFX radar loop showing base velocity around the time of warning issuance.

After this, it became clear that almost any shower in the area was capable of producing severe wind gusts due to the favorable low-level thermodynamics and we began looking for similar looking signals in the satellite and radar products. We then issued several more severe thunderstorm warnings as the line progressed eastward.

-ei2018

Cloud Obstruction with Octane Products

 A cold front swept across Western Pennsylvania and Northern West Virginia with a line of strong to severe thunderstorms that produced hail and wind damage. One thing to note about the Octane Cloud Top Cooling (CTC) imagery is that the anvil cirrus masked other storms in its wake. This might be a limiting factor for the Octane imagery, especially in linear storm events.

Figure 1: Anvil Cirrus was blown over other storms to the northeast and masked some overshooting tops/cloud top temperatures.

Shortly after, we noticed a similar problem so we then looked at the Octane Speed and Direction products in the mesosector. It is easier to make out the individual updrafts in these products as they appear less washed out and more defined. In this case, you can see 2 separate storms, one near Hundred, and one near Blacksville. These produced wind damage in northern West Virginia.

Figure 2: Octane Direction imagery in the mesosector.

Figure 3: Octane Speed imagery in the mesosector.

After seeing the initial problem, we changed the color table slightly in order to see if we can mitigate the masking issue. I personally like this color table more than the original but it still has the issue of masking other storms under the anvils. It is definitely easier to see individual storms but not as easy as the Octane Direction/Speed products.

Figure 4: New color table for the Octane CTC product.

-Batman