GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed strong southwesterly winds ahead of an approaching cold front, causing areas of blowing dust across parts of New Mexico, Texas and Oklahoma on 22 February 2023. Strongest wind gusts were in the 60-70 mph range, and blowing dust was reducing the surface visibility to 1.5 miles or less at some locations.

Max Wind Gusts – The axis of severe maximum gusts through 1:30pm CST have been from Hobbs and Tatum New Mexico into the southwestern South Plains to near Lubbock. Highest gusts have been 69mph at Plains and Denver City. #lubwx #txwx pic.twitter.com/3yD9gdXaXY

— NWS Lubbock (@NWSLubbock) February 22, 2023

A better signature of the blowing dust was seen in True Color RGB images — produced using Geo2Grid — from GOES-18 (GOES-West), GOES-17 and GOES-16 (below). GOES-17 (formerly GOES-West) was temporarily operating from its pre-storage checkout position over the Equator at 104.7 W longitude. Along the western edge of the widespread blowing dust, note the presence of a relatively narrow and brighter white plume (whose source region was White Sands National Park in New Mexico).

===== 23 February Update =====

On the following morning, the hazy signature of airborne dust was evident in GOES-16 True Color RGB images (from the GeoSphere site) over cloud-free areas of Illinois, Indiana, Ohio and Kentucky — and to a lesser extent, above the clouds in southern Lower Michigan (above).

Due to the more favorable forward scattering geometry associated with GOES-18 (below), the hazy blowing dust signature was apparent for a longer period of time — and farther to the east (eventually moving over West Virginia) — compared to what was seen in GOES-16 imagery.

HYSPLIT model forward trajectories — initialized at 3 points where the blowing dust appeared to be particularly dense at 0000 UTC on 23 February (below) — supported this pathway of long-range dust transport from New Mexico / Texas / Oklahoma to the lower Great Lakes and Ohio Valley 12-18 hours later.

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Indian Ocean Cyclone Freddy had an unusually long track and lifespan as it crossed the southern Indian Ocean. The animation above (created using geo2grid software) shows hourly Himawari-9 Clean Window infrared (10.4 µm) imagery from 5 February through 19 February, when Freddy could no longer be viewed by that geostationary satellite. Freddy appears over the eastern part of the domain on 6 February and shows a nice eye on the 11th of February, and again from 14-16 February, and at the end of the animation as well.

The MIMIC-TC animation, below, courtesy Derrick Herndon, CIMSS, shows how the microwave-sensed presentation of the storm evolved during its lifetime from 06 February through 22 February 2023. The maximum inferred windspeed, 135 knots, occurred twice, once on 16 February and once on 19 February. SATCON wind estimates, here, from this website, also showed the twin peaks in intensity.

MIMIC TPW fields, shown below as in an mp4 (Click here for an animated gif) also tracked Freddy across the Indian Ocean, from its formation near Australia on the 6th to its landfall in Madagascar on the 21st and Mozambique on the 24th.

NOAA/NESDIS has produced a story on Freddy, available here; the animation in that story is on YouTube.

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US Space Force EWS-G1 (formerly GOES-13) Infrared Window (10.7 µm) images (above) showed Category 3 Cyclone Freddy making landfall along the east coast of Madagascar on 21 February 2023.

According to products from the CIMSS Tropical Cyclones site, during the 12-15 hours leading up to landfall Freddy was traversing warm water with Sea Surface Temperature values of 28C, and moving through an environment characterized by low values of deep-layer wind shear (below).

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Heavy Rains overspread the Samoan Islands late on 20 February/early on 21 February 2023. ASCAT scatterometry from 0845 UTC on 21 February, above, (from this website), shows strong northerly winds Equatorward of the Samoan Islands, and weaker winds to the south: surface convergence is indicated. The animation below shows GOES-18 Visible imagery overlain on top of GOES-18 K-Index, one of the derived stability indices routinely produced. At this time, a large area of disturbed weather is located to the east of American Samoa.

The disturbed weather was associated with a trackable feature, a lowered tropopause, in gridded NUCAPS fields (available at this site). The lowered tropopause is highlighted in green values below and surrounded by higher tropopause values that are blue/cyan. This feature was attached to the lower tropopauses poleward of 30^oS (see this image from 2126 UTC on 20 February)

The animation below shows GOES-18 Band 13 Clean Window infrared (10.3 µm) imagery underlain with Clear-Sky-only estimates of K Index. Vigorous and persistent convection develops near Tutuila (America Samoa’s largest island) around 0700 UTC and continues through the end of the animation as it also builds northwestward over Western Samoa.

Flash Extent Density observations from the Geostationary Lightning Mapper (GLM) on GOES-18 show abundant lightning with the convection around the Samoan Islands.

What were the impacts from this convection? Flash Flooding occurred on American Samoa, as almost five inches of rain fell at the airport between 9 PM and 4 AM Samoa Standard Time (that is, 0800 UTC to 1500 UTC). In addition, Hawaiian Airlines Flight 465 (from Honolulu to Pago Pago) landed on time — but lightning prevented passengers from disembarking for 2 hours. Consequently, the return flight (Hawaiian Airlines Flight 466) was delayed 16 hours because of crew time constraint]

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Another heavy rain event across the islands of American Samoa was documented in February 2021.

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