GOES-16 (GOES-East) Mid-level Water Vapor (6.9 µm) images (above) showed the circulation associated with an anomalously-deep middle tropospheric cutoff low as it moved from northern Mexico across Texas during the 1301 UTC on 25 November to 2101 UTC on 26 November 2022 time period. Elevated convective elements rotating within the cutoff low helped to enhance precipitation rates in portions of western Texas and eastern New Mexico — with accumulating snowfall occurring at many locations.

As the system moved off to the east during the day on 26 November, GOES-16 “Red” Visible (0.64 µm) and Day Snow-Fog RGB images (below) revealed the extent of snow cover (darker shades of red in the RGB imagery) across parts of southeastern New Mexico and southwestern Texas.

In a toggle between GOES-16 Day Snow-Fog RGB and Land Surface Temperature (LST) derived product images at 2101 UTC (below), LST values over the deepest snow cover just west of the New Mexico / Texas border were as cold as the mid 30s F (compared to 50s and 60s F over bare ground just to the east and west of that snow cover). 12 UTC snow depth reports within that patch of snow cover were 4-5 inches.

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The Ahyi Seamount is an underwater volcano in the northern Marianas that rises to within 137 m of the Pacific Ocean surface (Click here for more information). VIIRS True-color imagery within the past week shows discoloration in the ocean over the seamount location, suggestive of some sort of eruptive activity. (See this News Article). The image above using Suomi NPP VIIRS data, (annotated images courtesy Meteorologist Nick Slaughter at the National Weather Service office on Guam), shows slight discoloration in the box centered on the seamount location. The NOAA-20 true-color image below, shows the evolution of the discoloration in the 45 minutes between images.

A second Suomi NPP Pass also viewed the scene at 0408 UTC on 25 November 2022 (NPP Orbits for the 25th can be viewed here; the NOAA-20 orbits are here). The movement of the discoloration, as noted by the annotations, differs from the atmospheric flow.

Suomi NPP and NOAA-20 data over Guam are provided by a Direct Broadcast antenna attached to the office. Data are processed for AWIPS using CSPP, the Community Satellite Processing Package, and Polar2Grid.

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Careful inspection of Suomi NPP True-Color imagery at the JStar Mapper reveals faint discoloration over the seamount on 23 November as well, as shown below.

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Many Thanks to Nick Slaughter, WFO GUM, for both the imagery and the information on this event!

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The 10th and final special RADARSAT-2 data collection of SAR winds over the Guam Area of Responsibility (AOR) occurred on 24 November, and is shown above in a toggle with the Himawari-8 Clean Window imagery at the same time (Here is the same toggle as above but with SAR data enhanced with a Beaufort Scaling, from 0-125 knots). Of note in this image is the feature with strong winds — up to 30 knots — to the west of Guam (Here’s a zoomed-in view). The curved westward edge suggests some type of outflow boundary perhaps, and the Himawari-8 imagery does show convection just to the east. Many people would be hard pressed to predict the distribution of winds in the SAR field below from the Himawari-8 imagery! The strongest winds are in a region centered on Rota — the island just northeast of Guam. It’s hard to see why that is based on the Himawari-8 Clean Window image. The arc of stronger winds from north-northwest of Guam is (at least) associated with clouds, albeit clouds with warm brightness temperatures.

Careful inspection of the imagery above (or the Normalized Radar Cross Section imagery available at this site), shows that the ships are back offshore of Saipan! They are apparent in the zoomed-in image below.

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Thanks to the SAR people at NOAA/STAR for supporting these special SAR data collections near Guam!

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5-minute GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), Fire Power derived product and Fire Temperature RGB images (above) displayed signatures of the wind-driven “Turkey Day” grassland fire in Oglala Lakota County in southwestern South Dakota on 23 November 2022. Peak 3.9 µm infrared brightness temperature (102.53ºC) and Fire Power (1570.84 MW) values were seen at 2006 UTC (the Fire Power derived product is a component of the GOES Fire Detection and Characterization Algorithm FDCA). Clouds began to move over the fire late in the day, thereby masking its thermal signature.

A toggle between Suomi-NPP VIIRS True Color RGB and False Color RGB images valid at 2016 UTC (below) provided a higher-resolution view of the narrow, dark burn scar as well as the smoke plume; in the False Color image, the hottest signature at the leading (southern) edge of the fire showed up as brighter shades of pink. Note how the fire’s burn scar initially moved eastward about 1 mile, but then  jogged toward the southeast as surface winds with gusts in the 20-26 knot range (Pine Ridge SD observations) abruptly shifted from westerly to northwesterly (in the wake of a cold frontal passage). The data to produce these VIIRS images were downloaded and processed using the SSEC/CIMSS Direct Broadcast ground station.

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