Gravity waves or other localized circulation in GXI synthetic imagery?

 Today’s GeoXO Imager (GXI) synthetic water vapor transmittance (WVT) imagery off the east coast of Florida/Georgia revealed a series of clear-sky ripple-like features approximately 100 miles off the eastern seaboard (Figure 1).  These features were moving toward the Florida coast in the dominant low-to-mid level northeasterly flow.

Although these ripples are reminiscent of gravity waves, their origin is not clear in this case; they are likely larger scale roll structures associated with shear in the marine environment.

Gravity waves were, however, clearly visible in real Flexible Combined Imager (FCI) WVT imagery over Africa earlier in the day (Figure 2).  Gravity waves are frequently observed in this region north of the ITCZ as waves propagate out of convective complexes.  These waves can be associated with airline turbulence as they propagate outward and upward away from their sources, so the ability to clearly see these waves in clear-sky regions is a benefit of the 0.91 µm channel coming to GXI.  Figure 3 shows the same scene in the 7.35 µm water vapor channel, where the waves are still visible, but considerably less well defined.

Figure 1: “WVT sandwich” product which features synthetic WVT in grayscale (brighter colors = more moist) with the synthetic 5.15 µm imagery overlaid in colors to highlight the location of colder-topped clouds.

Figure 2: Gravity waves from today in FCI WVT imagery over Africa. The waves appear as a series of dark ripples moving north near the center of the image, and likely originated with the ITCZ convection in the bottom-right corner of the image.

Figure 3: The gravity waves are still somewhat visible (though significantly less defined) in the FCI 7.35 µm low-level water vapor channel.  The clarity of the feature in the 0.91 µm-derived WVT product (Figure 2) presents an opportunity for novel uses of the new GXI channel to identify these waves.

VortexTilting

 The Flexible Combined Imager (FCI) from Meteosat-12 provides actual WVT imagery to complement the synthetic WVT imagery created over the CONUS.  The FCI captured a sea breeze over Tunisia and northwestern Libya on June 4.  The moisture moving onshore is marked by the southward moving dark areas denoted by the blue arrows.

Figure 1: FCI WVT image showing a sea breeze over Tunisia and northwestern Libya.

The difference in moisture is also clear when looking at vertical profiles on either side of the sea breeze front (Figs 2 and 3).  The profiles come from the 6hr forecast of the 12z run of the GFS from June 4, 2026.

Figure 2.  Blue and orange dots show approximate location of GFS profiles used to demonstrate the moisture difference across the sea breeze boundary.

Figure 3a. GFS profile in dry air south of the sea breeze front (near orange dot on Figure 2).

Figure 3b. GFS profile in moist air north of the sea breeze front (near blue dot on Figure 2).

One noteworthy aspect of the WVT is that it is not affected by surface or air temperature, something that is an issue when looking at moisture in infrared wavelengths.

Geogxi

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

Expanding my Horizons Beyond OCTANE

 Took a look at the WVT data from meteosat 12 this morning on the coast of the Red Sea and Yemen and western Saudi Arabia. Can see thunderstorms initiating off the higher terrain and very high WVT values along the coastline and low values inland. This was reflected very well by the surface dewpoints on the Synoptic viewer.

Figure 1: Meteosat 12 WVT band over western Saudi Arabia and Yemen

Figure 2: Synoptic viewer data 0800 hours PDT.

Finally got a chance to use stoplight data at Miles City, MT this afternoon. The product is easy to use for the cessation of lightning over an event. I did wish it was parallax corrected though. I was kind of guessing on the images and with the ENTLN lightning data when the last lightning strikes were.

Figure 3: GOES-19 SPoRT Lightning Stoplight and ENTLN 5 minute lightning data

One way to improve the data is to use the top right color scale with the stoplight product. This keeps the color flow smooth but adding a dark red for the very most recent lightning strikes proved to be the most helpful to me.

Figure 4: GOES-19 SPoRT Lightning Stoplight Product with 4 different color scales.

Dry Thunderstorms

Overview: Week 3, Day 4

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

Actual WVT Data from FCI

 One of the products demonstrated at this year’s HWT is synthetic water vapor transmittance (WVT) imagery.  The product, a ratio of 0.91 μm to 0.86 μm reflectances, is based on the existence of water vapor absorption at 0.91 μm.  Dividing by 0.86 μm helps to highlight the water vapor signature.  As NOAA does not yet operate a satellite channel at 0.91 μm, synthetic imagery is created for HWT from the High-Resolution Rapid Refresh model run through the Community Radiative Transfer Model.  However, EUMETSAT’s latest geostationary satellite, Meteosat-12, does contain 0.91 μm and 0.86 μm channels on its Flexible Combined Imager (FCI), and is used to augment the synthetic imagery during HWT.

Figure 1 shows an FCI WVT loop over northeastern Africa and the Arabian Peninsula from 3 June 2026.  The darker regions are indicative of higher amounts of total precipitable water (TPW).  Noteworthy regions of higher TPW can be seen along the west and south coasts of Saudi Arabia and Yemen as moisture moves onshore from the Red Sea and the Gulf of Aden.  The greater moisture along and equatorward of the Sahel is also very apparent.  Protruding from this reservoir of high TPW is a stream of moisture moving north to southern Algeria and then northeast towards Israel.  The existence of these high moisture areas can be confirmed by the corresponding TPW loop (Figure 2) created from blending retrievals from multiple polar-orbiting satellites.  Additional confirmation of the moisture protrusion over Algeria can be seen in the surface dewpoints at the reporting stations (Figure 3).  The stations in southeast Algeria have dewpoints above 40°F, whereas further north the dewpoints are 30°F or lower.

Figure 1.  WVT product loop over Africa on 3 June 2026.

Figure 2. Corresponding TPW product created from multiple polar-orbiting satellites.

Figure 3.  Surface observations over Algeria around 1300UTC 3 June 2026.  Dewpoint temperature (°F) is shown in blue.  Zooming in may be necessary to read the numbers.

Geogxi

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

GEOXO storm development and LightningCast DSS

 The GEOXO Sim 5.15um band and WVT ratio showed supercell or at least thunderstorm development near Gettysburg by 21Z. However the initialization of the upper level cirrus was underdeveloped and the main severe warned thunderstorm was farther north than observed. The lower level cumulus also appeared to be underdeveloped. There is a clear region in the sims where higher moisture is present and dryer air exists on either side, with the thunderstorms developing on the western boundary line.

Figure 1: GEOXO Sim 5.15um band and WVT ratio on top with observed GOES-19 IR an visible imagery on bottom. First frame shows Observations at around 20Z compared to the model and the second frame is in the future on the top an hour later.

While not severe or as intense as the Sim suggested, storms did develop and provided an interesting borderline case where LightningCastv1 showed barely 10% and v2 showed barely 30% chance of lightning in the next hour within 5 miles of the Gettysburg DSS location. A lightning strike occurred roughly miles from Gettysburg that was detected by the ENTLM and the Stoplight tool maybe 2 miles to the east. In this case, the addition of MRMS was clearly helpful in detecting the initial nearby convection.

Figure 2. LightningCast comparison between version 1 and 2 and parallax vs no parallax adjustment.

Cloudius

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

Moisture advancing east in pre-convective Wyoming environment

 Simulated GeoXO Imager (GXI) imagery revealed the westward extent of higher moisture in the pre-convective environment of eastern Wyoming this afternoon.

Figure 1 shows the water vapor transmittance (WVT, derived from the 0.91 µm channel) in the left panel and the 5.15 µm brightness temperature in the right panel over a five hour period from 16-20 UTC..  A dashed green line indicates the approximate westward extent of the deeper moisture as estimated from the WVT imagery. In this “inverted” color scheme, drier areas appear darker in WVT (as does higher terrain), and moister areas appear whiter; high-topped clouds generally appear dark.  In the last frame of the loop, convection initiates near Douglas along this moisture boundary on the southern end of this green line.

While WVT is sensitive to the total column water vapor, the 5.15 µm channel is only sensitive to water vapor in lower levels, where lower brightness temperatures generally coincide with higher low-level moisture.  It is interesting to note that the WVT and 5.15 µm gradients do not always align with each other, possibly suggesting an evolving vertical distribution of water vapor.  Our future plans include developing methods to utilize these differences to derive information about depth of moisture in the column.

Figure 1: WVT (left panel; inverted color scale so whiter colors=more moist). The green dashed line indicates the approximate westward extent of deeper moisture as estimated from WVT. 

VortexTilting

Dry Signals in Synthetic GeoXO

Today’s setup featured a typical high plains return flow pattern with low-level moisture upslope evident on surface observations and both the synthetic WVT & 5.15um channel imagery. One feature that caught my attention initially in the synthetic imagery was a dry pool over the Cheyenne Ridge, spanning from Weld County, CO up into Kimball County, NE (highlighted with yellow circle in the image below).  Observed surface dew points in this area were in the mid to upper 40s in southeasterly flow, likely on the leading edge of the plume of higher moisture in KS and CO. I did not see this level of detail on any other satellite imagery.

With this feature, I was curious on two fronts: the placement of this feature compared to reality, but also how would this dry pool affect convection later in the day. Compared with surface obs, the dry pool seemed to be slightly displaced to the east from reality, but not by far.  My gut was telling me that convective initiation on the Cheyenne Ridge itself would be nil due to the dry pool (perhaps with a hint of subsidence?), and that any established convection moving through the drier air would not exhibit explosive growth and would overall be weaker, and/or perhaps we’d see an enhanced downdraft wind threat. 

See below the loop of synthetic imagery highlighting the 5.15um imagery that covered the majority of our test period. Reality played out pretty close to the evolution of convection as seen in the loop. A left split fired off the mountains near Fort Collins and persisted northeast up into Wyoming. This storm produced severe hail slightly larger than quarter size in Cheyenne, but then appeared to weaken on visible satellite as it progressed further east-northeast along the Cheyenne Ridge where the drier air was forecast to reside.

This case shows the utility of highlighting moisture content, or lack thereof, that you cannot necessarily see on traditional satellite imagery.

Astrophage

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

Overview: Week 3, Day 1

 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