The Smokehouse Creek fire (inciweb link) as of 29 February is the largest fire in Texas history. VIIRS True-Color imagery above shows an extensive smoke plume (and a lot of other clouds!) over the eastern part of the north Texas Panhandle between 1830 and 2015 UTC on 27 February. Surface observations show very strong gusts from the west. In addition, a wind shift/cold front is moving southward into the domain by 2015 UTC, denoted by a line of cumulus cloud, with strong northerly winds behind it.

SPC’s fire weather outlook had parts of the north Texas panhandle in a critical fire weather outlook as shown below, especially because of strong wind gusts. The NWS in Lubbock has a fuel dryness image (the image for 27 February is here) and that shows the fire initiated in a region that was dry to critically dry. NWS Lubbock also has composite image for fire days (link). 27 February matches well.

The Next Generation Fire System (NGFS) has various imagery to help describe the current fire and its environment. For example, the imagery above from 2137 UTC on 27 February 2024, includes Fire Temperature RGB imagery (upper left), Day Fire RGB (upper right), GOES-West fire detection pixels (on top of True-color imagery, bottom left, and on top of a map, bottom right). This event included a large number of fire pixels detected, especially around the city of Canadian TX.

The animation of Fire Temperature RGB, below, from AWIPS, shows the evolution of the ongoing fire, and its interaction with a southward-moving cold front; when the front moves through the regions with fire (for example, near 2200 UTC in Canadian TX), the propagation of the fire switches from west-to-east to northwest-to-southeast. Satellite detection of the active fire is challenged at the end of the animation below because of increasingly thick upper-level clouds moving in from the southwest.

Night Microphysics RGB imagery, below, from the CSPP Geosphere site, show thick clouds over the fire region initially; by the end of the animation, however, hot spots in the Night Microphysics RGB (pixels that are magenta/pink) start to emerge.

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Day Night Band imagery from early on 28 February, reveals the light emitted from the fires. The I04 shortwave infrared (3.74 µm) imagery shows the heat signatures — that can help a user unfamiliar with a location differentiate fire signatures from urban lights. Relatively clear skies at 0823 UTC (on the left, click here for a toggle between the two VIIRS images at that time) allow an unimpeded view of the fires. By 0932 UTC (on the right, click here for a toggle between the two VIIRS images at that time), however, cirrus streaming in from the southwest is interfering with the satellite’s ability to detect hot spots although the light from the fires is able to penetrate the cloud deck.

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VIIRS imagery from during the day on 28 February 2024, below, defines the large outline of the burnscar. The scar in the visible (0.64 µm) imagery is not quite so distinct as it is in 0.87 µm and 1.61 µm. The 3.74 µm (shortwave infrared) suggests that burning is continuing on 28 February. The False Color imagery uses information from the 1.61 µm and 0.87 µm bands. The burn scar is extensive, covering almost the entirety of several Texas counties!

In a toggle between VIIRS False Color RGB imagery and the GOES-16 Land Surface Temperature (LST) derived product at 1900 UTC (below), LST values were up to 10ºF warmer (mid 80s F, darker shades of red) within darker-colored portions of the Smokehouse Creek Fire (in Roberts and Hutchinson counties) and Windy Deuce Fire (in Carson county) burn scars — compared to lighter-colored northern areas of the Smokehouse Creek burn scar (where LST values were mainly in the mid 70s F, shades of green). The presence of lingering smoke (which was incorrectly classified as Cloudy in the Clear Sky Mask derived product) prevented the derivation of LST values over all parts of those 2 burn scars.

Note that the large Smokehouse Creek Fire burn scar extended several miles eastward across the Texas/Oklahoma border, into parts of Ellis and Roger Hills counties.

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The Smokehouse Creek Fire began during the afternoon hours on 26 February, and 1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Shortwave Infrared (3.9 µm) images (above) showed the rapid eastward run during its initial 7 hours — covering a distance of about 50 miles across Hutchinson and Roberts counties in the Texas Panhandle. Rapid eastward runs of the Grape Vine Creek Fire in Gray county and the Windy Deuce Fire along the Potter/Moore county line were also seen.

1-minute GOES-18 Shortwave Infrared images along with the Fire Power, Fire Mask and Fire Temperature derived products (3 components of the GOES Fire Detection and Characterization Algorithm FDCA) provided additional quantitative information about the fire during its eastward run (below). Although the InciWeb report listed the fire origin time as 14:20 CST (2020 UTC) just north of Stinnett in Hutchinson county, the initial signature in the GOES-18 FDCA products appeared at 1856 UTC (12:56 PM CST).

The Smokehouse Creek Fire burned very hot, exhibiting a maximum 3.9 µm infrared brightness temperature of 137.88ºC (which is the saturation temperature of the GOES-18 ABI Band 7 detectors) as early as 2104 UTC in eastern Hutchinson county (below). At that time and location, the derived Fire Power value was 3678.88 MW and the derived Fire Temperature value was 1742.32 K.

A longer (53-hour) animation of 5-minute GOES-16 (GOES-East) Shortwave Infrared images — centered on the Smokehouse Creek Fire — from 26-28 February (below) illustrated (1) the initial eastward run of the fire on 26 February, (2) the rapid increase in areal coverage and eastward expansion into far western Oklahoma on 27 February, as westerly winds increased in speed during the day (3) the abrupt southward expansion following the passage of a strong cold front late in the day on 27 February — note the shift from westerly to northerly winds in a plot of surface data from Borger Hutchinson County Airport (KBGD), and (4) the periodic masking of the fire signature as a patches of mid/high clouds moved across the region on 28 February.

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CIMSS Scientists who work with JPSS data had numerous presentations at the American Meteorological Society’s Annual Meeting held at the end of January in Baltimore. This blog post discusses a poster by Tom Greenwald who (along with co-authors) investigated how microwave data from AMSR-2 can be used to estimate sea ice concentration in regions where very high-resolution Synthetic Aperture Radar (SAR) data are not present. The AMSR-2 images were validated using very high-resolution Landsat visible imagery; that is, this was done in regions of clear skies to show that the microwave data would be producing useful information in regions of clouds. The high-resolution AMSR-2 Sea Ice Concentration data are used, as the poster notes, to “track the ice edge and marginal ice zone (MIZ) with a degree of confidence not achieved with the standard AMSR2 sea ice concentration.”

A dedicated CIMSS Satellite Blog reader might recall past blog posts that also discussed this technique, here and here. AMSR-2 gives high-resolution, quality sea ice detection to augment SAR observations. Future work includes a more thorough comparison between this product and legacy products. A Quick Guide on this product is available here.

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5-minute CONUS Sector GOES-16 (GOES-East) True Color RGB images + Nighttime Microphysics RGB images from the CSPP GeoSphere site (above) showed large smoke plumes produced by 2 wind-driven grass fires in central Nebraska (just north of North Platte) on 26 February 2024. The burn scar associated with the larger (southernmost) fire was very apparent, as a west-to-east oriented swath of darker brown shades. After sunset, the hot fire signatures showed up as clusters of darker purple pixels in Nighttime Microphysics RGB imagery.

In a toggle between Suomi-NPP VIIRS True Color RGB and False Color RGB images valid at 1950 UTC (above), a more detailed view of the burn scar was seen in the True Color RGB image — with the hot thermal signatures of active fires exhibiting brighter shades of pink to red. The head of the fire was close to the Lincoln County / Custer County line at that time. A sequence of 3 VIIRS Shortwave Infrared (3.74 µm) images from NOAA-20 and Suomi-NPP (below) provided a high-resolution view of how quickly the fire’s leading edge moved eastward in a time span of about 1 hour and 40 minutes. The VIIRS data used to create these images were received and processed using the CIMSS/SSEC Direct Broadcast ground station.

1-minute Mesoscale Domain Sector GOES-16 Fire Temperature RGB images along with the Fire Power, Fire Mask and Fire Temperature derived products (below) provided a closer view of the southern grass fire thermal signature and its rapid eastward run toward (and eventually across) the Lincoln County / Custer County line (the Fire Power, Fire Mask and Fire Temperature derived products are components of the GOES Fire Detection and Characterization Algorithm FDCA). Distinct thermal signatures of the fire were evident beginning at 1644 UTC — which advanced quickly eastward due to winds gusting as high as 42 knots (49 mph) at North Platte (KLBF).

Parts of this fast-moving grass fire burned very hot at times — in fact, a cursor sample of GOES-16 Fire Temperature RGB and Fire Mask at 2000 UTC (below) showed that the fire exhibited a maximum 3.9 µm infrared brightness temperature of 138.71ºC (which is the saturation temperature of the GOES-16 ABI Band 7 detectors). The Fire Mask product helps to quickly identify such “Saturated Fire” pixels by highlighting them as bright yellow. In addition, maximum Fire Power values exceeded 2500 MW.

The #Nebraska #fire from GOES-16 True Color RGB and 3.9um temps overlaid with the KLNX (North Platte) radar data. Base reflectivity shows the smoke plume, along with the 3D vertical cross section and 20dBZ isosurface (anywhere 20dBZ is detected across elevation angles). #mcidas pic.twitter.com/qo95yeVyxP

— Robert Carp (@rmcarp) February 26, 2024

During the following nighttime hours, a toggle between Suomi-NPP (mislabeled as NOAA-20) VIIRS Day/Night Band (0.7 µm) and Shortwave Infrared (3.74 µm) images (above) showed the area of the grass fire at 0808 UTC (2:08 AM CST) on 27 February. Due to ample illumination from the Moon — which was in the Waning Gibbous phase, at 92% of Full — darker areas of burned grassland could be seen, extending just across the Lincoln County / Custer County border. Although most of the fire had ended (since wind speeds decreased dramatically after sunset), a few clusters of warmer pixels remained along the perimeter of the burn scar.

 

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The GXS is the sounder that is proposed to be part of the GeoXO constellation of satellites that will launch starting in the 2030s as a replacement to the GOES-R satellites. (Note: GOES-U is now scheduled to launch no earlier than mid-May 2024). Beyond the GXS uses of radiance assimilation into global and regional models, there will be many applications associated with nowcasting. This post highlights one related to convection. What kind of capabilities will the GXS bring? That’s shown in the animation above. The left-hand imagery shows the theta_e(500) – theta_e(850) values computed from simulated sounder data: The extra fine spatial resolution (1-km) nature run (XNR1K) from the ECMWF model was averaged over the Sounder field of view (FOV), and a radiative transfer model was used to create Top of Atmosphere (TOA) radiances at all GXS sounder channels. Subsequently, temperature/moisture profiles were retrieved from these simulated sounder TOA observations using a deep neural network model. The retrievals are derived based on GXS radiances only (no NWP forecast used as first guess or background). Theta-e values at 850 hPa, 500 hPa were calculated from the retrieved T/Q profiles. The right-hand imagery shows theta_e(500) – theta_e(850) values calculated from the averaged XNR1K profiles (averaged to the Sounder field of view), which are used here as truth for validation.

There is remarkable similarity between the two fields, meaning the sounder data can give accurate estimates of potential instability, that is, theta_e(500) – theta_e(850). If theta_e is decreasing strongly with height, atmospheric lift will lead to the rapid release of instability driven by strong latent heat release. In the animation above, strong convection develops near the strong negative values of theta_e(500) – theta_e(850) (red values); you can also see stable regions (in green/blue) near strong convection where cool downdrafts have stabilized the atmosphere. That’s also apparent in the shorter animations below: 2000 UTC on 6 September – 0000 UTC on 7 September and 0200 UTC – 0545 UTC on 7 September. The simulated GXS data here can alert a forecaster to where convection might (or might not) soon occur. There is a marked tendency for the convection to occur near gradients of potential instability.

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The following figure shows forecast model output estimates of precipitation at 1700, 1800 and 1900 UTC on 6 September 2019. The focus here is on the convection moving from Kansas into Nebraska, circled in purple. Figures below that describe how the convection relates to sounder-derived potential instability.

Convection develops at the leading edge of the diagnosed instability, the boundary between deep reds and yellows. The model output and sounding-consistent retrievals based on the model output show pools of stability near the developing convection (yellows and greens in the enhancement).

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