JMA Himawari-8 Dust RGB images (created using Geo2Grid) covering the 48-hour period from 21 UTC on 04 May to 21 UTC on 06 May 2021 (above) revealed multiple plumes of blowing dust (brighter shades magenta/pink) which originated over parts of Mongolia — and were then transported southeastward and eastward across northeastern China.

Surface analyses from the Korean Meteorological Agency (below) showed an impressive pressure gradient between a midlatidude cyclone (moving southeastward from Mongolia into China) and high pressure moving southward behind it. Some of the airborne dust was entrained into the circulation of this low pressure system.

VIIRS True Color RGB mages from Suomi NPP and NOAA-20 viewed using RealEarth (below) showed the hazy arc of blowing dust along the trailing cold front (south of the cyclone in northeastern China) on 6 May.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) include time-matched plots of SPC Storm Reports (predominantly widespread damaging winds, with some large hail and a few tornadoes) produced by a large and long-lived Mesoscale Convective System (MCS) that moved eastward across much of Mississippi and Alabama on 04 May 2021. The strong winds — with some gusts in excess of 70 mph — caused power outages which affected several hundred thousand residents (and persisted into the next day: MS | AL).

The corresponding 1-minute GOES-16 “Clean” Infrared Window (10.35 µm) images (below) showed numerous overshooting tops that exhibited infrared brightness temperatures in the -75 to -70ºC range (white pixels embedded within black areas). The MCS also produced heavy rainfall and flooding in parts of northern Alabama.

? It rained a little yesterday…

Rainfall totals of 5-7″ (locally higher) fell across parts of the Birmingham metro & much of Shelby Counties. This lead to significant flooding in many areas. Thankfully, there were no fatalities. #alwx pic.twitter.com/ko0TmYhNUo

— NWS Birmingham (@NWSBirmingham) May 5, 2021

Larger-scale views of 5-minute CONUS Sector GOES-16 Visible and Infrared images are shown below. Several additional MCSs produced a variety of severe weather across other parts of the Southeast US.

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The NOAA/CIMSS ProbSevere portfolio contains AI models for nowcasting convective weather. I’ll use Monday’s severe weather over the Southern Plains to highlight several of them.

A strong cold front spawned numerous severe-hail, wind, and tornado producing storms over Texas and Oklahoma, aided by very large values of convective available potential energy (CAPE; > 4000 J/kg).  You can see numerous storm reports in Figure 1.

Probsevere version 2 (PSv2) is an operational set of models at NOAA, which predict the probability of severe hail, severe wind, and tornadoes, in the next 60 minutes. The models are storm-centric, and the models’ domain is the entire contiguous United States (CONUS).  These models use MRMS (radar), GOES (satellite), short-term NWP, and terrestrial-based lightning observations to generate probabilistic guidance of severe hazards. Figure 2 shows output from an experimental version (PSv3), which includes additional MRMS, GOES, and NWP fields as predictors in a machine learning model.

 

Another ProbSevere product is a convolutional neural network that uses GOES-R ABI and GLM images to detect regions of intense convection, and is often correlated with strong overshooting tops, “bubbly-like” texture in visible imagery, strong lightning cores, and the cold-U/above-anvil cirrus plume signature. The intense convection probability (ICP) can be run on the 1-minute mesoscale scans as well as 5-minute CONUS sector scans aboard the GOES satellites. The ICP does not require radar data, and may also be able to operate on data from satellites with similar intruments (e.g., Meteosat Third Generation). ICP output is being used as a predictor in the experimental ProbSevere v3.

 

Predicting when and where lightning will occur is also important for many users, such as mariners, aviators, and outdoor event managers. The probability of lightning model (PLTG) is also a convolutional neural network, using images of visible, near-infrared, and longwave-infrared channels to nowcast lightning occurrence in the next 60 minutes. The purple-to-orange shaded regions in the video below show GLM flash-extent density (i.e., flashes passing through a location).

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm), CIMSS Natural Color RGB and Dust RGB images (above) showed a pulse of blowing dust moving southward within the outflow of a severe thunderstorm in southeastern Colorado on 02 May 2021. The storm produced a tornado, large hail and wind gusts as high as 93 mph at Lamar (KLAA) at 2309 UTC (SPC Storm Reports). The blowing dust eventually reduced surface visibility to 1 mile at Johnson City as it moved across far western Kansas.

1-minute GOES-16 True Color RGB images created using Geo2Grid (below) highlighted the characteristic tan-colored hues of blowing dust along and behind the thunderstorm outflow boundary.

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