GOES-16 (GOES-East) Split Window Difference images (above) showed widespread strong winds across the Dakotas and northern Minnesota which were responsible for producing plumes of blowing dust (darker shades of gray) — most notably from eastern North Dakota into northwestern Minnesota — on 24 May 2021.

The corresponding GOES-16 Split Window Difference images with plots of surface visibility are shown below — at 23 UTC the visibility dropped to 4 miles at Grand Forks, North Dakota as a dense dust plume moved through that location (where southwesterly winds were gusting to 31 knots at that time).

GOES-16 True Color RGB images (above) and Dust RGB images (below) created using Geo2Grid highlighted the more dense plumes of blowing dust — the source region for the more prominent dust plumes appeared to be dry agricultural fields in southeastern North Dakota that had received very little rainfall during the preceding week.

Ground-based lidar data from Grand Forks indicated that the dust was lofted to altitudes of around 10,000 feet.

Plenty of backscatter thanks to the dust pic.twitter.com/bQDpSIwXry

— Aaron Kennedy (@KennedyClouds) May 24, 2021

===== 25 May Update =====

Strong winds persisted across that same region on 25 May — and GOES-16 Dust RGB images (above) again displayed the subtle signature of blowing dust (light shades of pink/magenta) along the leading edge of cloudiness that was moving eastward into northwestern Minnesota.

GOES-16 True Color RGB images (below) once again showed the hazy signature of blowing dust.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) displayed the exposed low-level circulation of Invest 90L, in the Atlantic Ocean (about 150 miles northeast of Bermuda, TXKF) on 21 May 2021.

GOES-16 Visible images with plots of Visible Derived Motion Winds (below) revealed a few wind speeds of 50 knots or greater (red wind barbs) within its northwest quadrant — but since no organized and sustained deep convection remained in close proximity to the low-level circulation, Invest 90L was not yet considered to be a tropical cyclone.

===== 22 May Update =====

During the overnight hours, convection organized and intensified around the low-level circulation of Invest 90L — and as of 0900 UTC it was classified as Subtropical Storm Ana. GOES-16 Infrared images of Ana are shown above.

A closer view of GOES-16 Visible images (below) indicated that the center of Ana eventually stopped moving southwestward toward Bermuda, performed a counterclockwise loop, then began moving to the northeast.

GOES-16 Visible images with plots of Derived Motion Winds (below) indicated that the maximum near-surface wind speeds were 39 knots.

An overpass of Metop-A at 1219 UTC provided ASCAT surface scatterometer winds centered on Ana (above), with a maximum speed value of 31 knots just northwest of the storm center. In general, Visible GOES-16 Derived Motion Wind speed values were around 5 knots faster than nearby ASCAT winds (below) — since the former are computed by tracking cloud targets that are above the surface, where winds speeds are greater (due to a lack of surface friction).

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1-minute Mesoscale Domain Sector GOES-17 (GOES-West) Shortwave Infrared (3.9 µm) and “Red” Visible (0.64 µm) images along with 5-minute GOES-16 (GOES-East) Fire Power and Fire Temperature products (above) displayed thermal characteristics and the smoke plume associated with the Cherrywood Fire in southern Nevada on 20 May 2021. The maximum 3.9 µm brightness temperature sensed was 138.7ºC — which is the saturation temperature for the ABI Band 7 detectors. The peak Fire Power values exceeded 4000 MW.

A toggle between NOAA-20 VIIRS Shortwave Infrared (3.74 µm) and True Color RGB images at 2014 UTC (overpass times) is shown below.

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GOES-16 (GOES-East) True Color RGB images created using Geo2Grid (above) showed the growth of numerous large smoke plumes created by wildfires across parts of Manitoba and Ontario on 18 May 2021. A “pyrocumulus jump” was seen in Manitoba (just south of Lake Winnipeg) just after 00 UTC.

Early in the day, a significant amount of ice coverage was apparent in the northern portion of Lake Winnipeg (before becoming obscured by dense smoke plumes). In addition, a line of thunderstorms developed across Saskatchewan and Montana ahead of an approaching cold front.

===== 19 May Update =====

In a toggle between Suomi NPP VIIRS Shortwave Infrared and Day/Night Band images at 0811 UTC or 3:11 AM CDT on 19 May (above), the thermal signature of the large fire between Lake Manitoba and Lake Winnipeg was obscured by a narrow patch of cloudiness, but the bright signature of active fires still burning along the periphery of the original wildfire burn area was apparent in the Day/Night Band image.

The GOES-16 Aerosol Optical Depth product (below) highlighted a plume of smoke aloft — originating from the Manitoba/Ontario fires — moving southward across Quebec, Canada and the Northeast US during the subsequent daytime hours. AOD values were as high as 1.0 within the plume.

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