NUCAPS’ description of a post-frontal atmosphere

March 31st, 2021 |

GOES-16 ABI Band 02 (0.64 µm) visible imagery, 1901 UTC, and NUCAPS estimates of Lapse Rate and Mixing Ratio at 925-700 mb, and 700-300 mb (Click to enlarge)

The animation above cycles through GOES-16 Visible Imagery (0.64 µm) at 1901 UTC as well as simultaneous observations (from NUCAPS) of Lapse Rates (925-700 mb and 700-300 mb) and Mixing Ratio (925-700 mb and 700-300 mb). Thermodynamic information from NUCAPS complements information about the atmosphere that can be inferred by the GOES-16 imagery.

There are very strong low-level (925-700) lapse rates around Missouri behind the cold front that stretches over the south.   The atmosphere there is also very dry.  The smaller lapse rates at higher altitudes (700-300) also are in a region of very dry air.   NUCAPS Soundings from Des Moines, Kansas City and St Louis show the inversion that exists between the steep low-level lapse rates and smaller upper-level lapse rates. There is a much smaller change in lapse rates over the southeastern United States, with small stability all through the troposphere.

NUCAPS thermodynamic fields also capture the relatively moist air within the cloud features in northeastern Iowa, with strong low-level lapse rates on either side of the cloud field there.

Wildfires in South Dakota

March 29th, 2021 |

GOES-16 Shortwave Infrared images, with hourly surface wind barbs (cyan) and gusts (in knots, red); Interstate 90 is plotted in red [click to play animation | MP4]

GOES-16 Shortwave Infrared (3.9 µm) images, with hourly surface wind barbs (cyan) and gusts (in knots, red); Interstate 90 is plotted in red [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) Shortwave Infrared (3.9 µm) images (above) displayed the thermal anomalies (clusters of hot pixels) associated with 2 wildfires burning in western South Dakota on 29 March 2021. One fire began just west of Rapid City around 1530 UTC — which forced some evacuations. A second fire began just north of Interstate 90 around 1730 UTC — which forced the closure of Interstate 90 between Kadoka and Murdo as strong northwesterly winds in the wake of a cold frontal passage (surface analyses) caused a rapid fire run to the southeast. The southern surge of cold air (lighter shades of gray) behind the cold front could also be seen in the Shortwave Infrared images; both fires began shortly before the arrival of the cold front.

Taking a closer look at the fire just west of Rapid City, a 4-panel comparison of GOES-16 Fire Temperature RGB, Shortwave Infrared, Fire Power and Fire Temperature Characterization products (below) showed that this was not a particularly large or hot fire, whose signature was sometimes obscured by clouds moving overhead.

GOES-16 Fire Temperature RGB (top left), Shortwave Infrared (top right), Fire Power (bottom left) and Fire Temperature (bottom right) [click to play animation | MP4]

GOES-16 Fire Temperature RGB (top left), Shortwave Infrared (3.9 µm, top right), Fire Power (bottom left) and Fire Temperature (bottom right) [click to play animation | MP4]

===== 30 March Update =====

GOES-16

GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Vegetation” (0.86 µm) and Day Land Cloud Fire RGB images [click to play animation | MP4]

On the following day, GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Vegetation” (0.86 µm) and Day Land Cloud Fire RGB images (above) revealed the northwest-to-southeast oriented burn scar (darker gray pixels).

1984: Carolinas Tornado Outbreak

March 29th, 2021 |

NOAA’s GOES-5 VISSR view of a historical outbreak in the Carolina’s in 1984. March 28th and 29th, 1984 saw one of the most destructive tornado events in the history of North and South Carolina.

Infrared Loop:

GOES-5 Infrared imagery from 12:00 UTC to 23:30 UTC on March 28, 1984.

The coldest clouds appear as darker shades of red. A regional scale IR loop.

Visible Loop:

GOES-5 visible imagery from 12:00 UTC to 23:30 UTC on March 28, 1984.

A more zoomed-in visible loop over the same time range.

H/T Melissa Griffin for reminding us of this case:

More background on this case in 1984 was posted by the NWS Willmington office: https://www.weather.gov/ilm/CarolinasOutbreak.

A combined visible and infrared GOES-5 Full Disk image from March 28, 1984 at 21 UTC.

A larger Full Disk “sandwich” image.

NOAA GOES-5 data are via the University of Wisconsin-Madison SSEC Satellite Data Services.

Flooding in Tennessee

March 28th, 2021 |

GOES-16 “Clean” Infrared Window (10.35 µm) images, with hourly Precipitation Type plotted in cyan [click to play animation | MP4]

GOES-16 “Clean” Infrared Window (10.35 µm) images, with hourly Precipitation Type plotted in cyan [click to play animation | MP4]

GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) images centered on Nashville (above) displayed multiple clusters of thunderstorms that moved across Tennessee during the 27 March – 28 March 2021. The coldest overshooting top infrared brightness temperatures were in the -70 to -79C range. Precipitation ended and clouds cleared as a cold front moved eastward across the state on 28 March.

Hourly images of the MIMIC TPW product (below) showed the northward surge of moisture from the Gulf of Mexico beginning early on 27 March, providing an environment conducive to heavy rainfall.

MIMIC TPW product [click to play animation | MP4]

MIMIC TPW product [click to play animation | MP4]

Plots of rawinsonde data from 00 UTC and 12 UTC on 27 March [click to enlarge]

Plots of Nashville rawinsonde data from 00 UTC and 12 UTC on 27 March [click to enlarge]

Plots of Nashville rawinsonde data from 00 UTC and 12 UTC on 27 March (above) and 28 March (below) illustrated the rapid increase in moisture on 27 March, followed by the gradual decease in the wake of the cold frontal passage.

Plots of rawinsonde data from 00 UTC and 12 UTC on 28 March [click to enlarge]

Plots of Nashville rawinsonde data from 00 UTC and 12 UTC on 28 March [click to enlarge]

 

 


CMORPH estimates of accumulated precipitation (available in RealEarth) are shown below, with 24-hour totals ending 23:59 on 27 March (left) and 28 March (right).  The darker purple region denotes totals of >100 mm in 24 hours.

24-hour precipitation totals ending 23:59 on 27 March (left) and at 23:59 28 March (right) 2021 (Click to enlarge)