Severe weather across much of the Southeast US

May 4th, 2021 |

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play animation | MP4]

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.

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

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



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.

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images, with SPC Storm Reports plotted in red [click to play animation | MP4]

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

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

ProbSevere products over the Southern Plains

May 3rd, 2021 |

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.

210503_rpts Reports Graphic

Storm Prediction Center’s preliminary severe storm reports for May 3rd, 2021.

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.

Figure 2: ProbSevere v3 contours (colored, around storms), MRMS MergedReflectivity, and NWS severe weather warnings (yellow and red boxes) for storms over the Southern Plains. The second outer contour around some storms is colored by the probability of tornado.

 

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).

Blowing dust behind the outflow of a severe thunderstorm in Colorado

May 2nd, 2021 |

GOES-16

GOES-16 “Red” Visible (0.64 µm), CIMSS Natural Color RGB and Dust RGB images [click to play animation | MP4]

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.

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images [click to play animation | MP4]

Large hail in Texas

April 28th, 2021 |

GOES-16 “Red” Visible (0.64 µm) images and “Clean” Infrared Window (10.35 µm) images, with plots of SPC Storm Reports [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images (top) and “Clean” Infrared Window (10.35 µm) images (bottom), with plots of SPC Storm Reports [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images and “Clean” Infrared Window (10.35 µm) images (above) include time-matched plots of SPC Storm Reports of large hail produced by supercell thunderstorms that developed and moved eastward across southern Texas on 28 April 2021. Hail as large as 4.00 inches in diameter was listed in the SPC Storm Reports, but one giant hailstone was found whose diameter was 6.4 inches:


Vigorous overshooting tops were seen in both the Visible and Infrared GOES-16 images, with the coldest IR brightness temperatures in the -80 to -89ºC range (shades of violet to purple) — and along the southern flank of the storms, inflow feeder bands were evident the Visible imagery. 00 UTC rawinsonde data from Del Rio, Texas (below) showed that parcel temperatures of -80 to -89ºC would indicate significant vertical overshoots of both the equilibrium level (-67ºC) and the tropopause (-74.7ºC).

Plot of rawinsonde data from Del Rio, Texas [click to enlarge]

Plot of rawinsonde data from Del Rio, Texas [click to enlarge]

Farther to the north, 1-minute GOES-16 Infrared images (below) showed other thunderstorms that produced large hail (up to 3.25 inches in diameter) in the Dallas/Fort Worth area after sunset.

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

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