1-minute GOES-16 (GOES-East) Mesoscale Domain Sector “Red” Visible (0.64 µm) images (above) included time-matched (+/- 4 minutes) plots of SPC Storm Reports — which showed thunderstorms that moved northeastward across parts of Texas, Oklahoma, Arkansas and Louisiana during the hours leading up to sunset on 04 November 2022.

The corresponding 1-minute GOES-16 “Clean” Infrared Window (10.35 µm) images  (below) continued for several hours past sunset — and indicated that the coldest pulsing overshooting tops exhibited infrared brightness temperatures in the -70 to -75ºC range (interior pixels having a darker black to lighter white enhancement). These storms produced hail up to 2.75 inches in diameter in Texas, and damaging winds up to 108 mph in Oklahoma — along with widespread tornadoes (with some resulting in fatalities). The EF-4 tornado which tracked from Red River County, TX to McCurtain County, OK was the first EF-4 tornado in NWS Shreveport’s County Warning Area since 29 November 2010, and the first Oklahoma EF-4 since 09 May 2016.

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GOES-16 (GOES-East) Mid-Level Water Vapor (6.9 µm) and Air Mass RGB images (above) covered the period 0600-1800 UTC on 03 November 2022 — during which Category 1 Hurricane Martin transitioned to an extratropical cyclone over the North Atlantic Ocean (surface analyses). West of Martin, the large area of orange-to-red hues on the Air Mass RGB images highlighted an anomalously-deep mid-tropospheric trough that was moving eastward (also shown by UKMET model 500 hPa height contours) — which began to phase with and absorb the mid-tropospheric circulation of Martin as the extratropical transition completed.

DMSP-17 SSMIS Microwave (85 GHz) imagery at 1005 UTC (below) — from the CIMSS Tropical Cyclones site — indicated that a closed eyewall was not present with Martin at that time.

VIIRS True Color RGB and Infrared Window (11.45 µm) images from Suomi-NPP (at 1447 UTC) and NOAA-20 (at 1537 UTC) viewed using RealEarth (below) showed Martin around the time that extratropical transition was nearly complete.

GOES-16 Nighttime Microphysics RGB and daytime True Color RGB images from the CSPP GeoSphere site (below) displayed the center of Martin moving rapidly north-northeastward (at speeds of 40-50 knots) during the day.

Additional imagery of Martin can be seen in this blog post.

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Hurricane Martin, now in the north Atlantic, continues to move northeast and is expected to become a post-tropical cyclone in the next few hours. It was named a Hurricane on Wednesday, 2022-11-02 around 15UTC. Its maximum sustained winds are 85 mph (140 km/h). By the weekend, Martin’s swells will be affecting parts of Canada, the Azores, and coastal regions of western Europe. Hurricane Martin’s forecast cone is provided by the National Hurricane Center.

Meanwhile in the Gulf and Caribbean, Lisa has left much of Belize’s population to deal with its damages. Lisa upgraded to hurricane status on 2022-11-02 around 12UTC, and downgraded to tropical storm about fifteen hours later, after making landfall in Belize. As of 11-3-2022 at 15UTC, Lisa has weakened to a depression.

Animations that span several days can be easily made using RealEarth, a free tool for visualizing satellite data products. It is great for things like tracking multiple hurricanes across the Atlantic. Animation and map settings are customizable, and you can even view multiple spectral bands from satellites like GOES-16 (i.e. GOES-East).

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After a request from the National Weather Service Pacific Region, Synthetic Aperture Radar (SAR) data are available over/around Guam. These data are available at this NOAA/NESDIS website, and also via anonymous ftp from ftp.star.nesdis.noaa.gov. There will be 10 overpasses between 1 and 24 November. The first RADARSAT overpass occurred at 0839 UTC on 3 November, and it is shown above in a toggle with Himawair-8 Band 13 imagery. Very strong convection to the southwest of Guam (inferred from the cloud tops as cold as -90^oC — the purple enhancement within the white) is associated with surface winds exceeding 40 knots. A zoomed-in toggle is shown below.

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Radar estimates of hourly rainfall ending at 0839 UTC, below, (courtesy Brandon Aydlett, SOO at WFO Guam) show a large region with totals exceeding 1 inch during the previous 60 minutes, with small regions of 1.5 – 2 inches apparent.

The presence of ice in a cloud will increase SAR backscatter, and when that happens, wind speeds that are larger than observed will be indicated. This is probably happening on this day. NRCS (Normalized Radar Cross Section) imagery from this time, available here, from this website, and shown below (with computed wind speeds shown beneath that — you’ll see they match the AWIPS presentation above), show the characteristic feathery appearance that accompanies SAR detection in regions of significant cloud ice. The conclusion would be that this convection with very cold cloud tops was likely not producing very strong surface winds at 0839 UTC.

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The SAR-derived light winds that are occurring near Guam are in agreement with Advanced Scatterometer (ASCAT) data from MetopB (shown below) and MetopC (here), and from windspeed observations from AMSR-2 on GCOM-W1 (here), as taken from the NOAA ‘manati’ website.

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