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).

Rapid intensification of Super Typhoon Surigae

April 16th, 2021 |

JMA Himawari-8 Infrared Window (10.4 µm) images [click to play animation]

JMA Himawari-8 Infrared Window (10.4 µm) images [click to play animation]

2.5-minute interval rapid scan JMA Himawari-8 Infrared Window (10.4 µm) images (above) showed Typhoon Surigae undergoing rapid intensification (ADT | SATCON) to become a Category 4 storm as of 18 UTC on 16 April 2021.

A DMSP-16 SSMIS Microwave (85 GHz) image from the CIMSS Tropical Cyclones site (below) displayed a well-defined eye, with distinct spiral bands feeding into the eyewall.

DMSP-16 SSMIS Microwave (85 GHz) image at 1944 UTC [click to enlarge]

DMSP-16 SSMIS Microwave (85 GHz) image at 1944 UTC [click to enlarge]

After sunrise, Himawari-8 “Red” Visible (0.64 µm) images (below) showed the relatively compact eye, with hints of low-level mesovortices within the eye.

JMA Himawari-8 "Red" Visible (0.64 µm) images [click to play animation]

JMA Himawari-8 “Red” Visible (0.64 µm) images [click to play animation]

===== 17 April Update =====

JMA Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

JMA Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

The prolonged period of rapid intensification continued overnight, and as of 12 UTC on 17 April Surigae had become a Category 5 Super Typhoon — 2.5-minute interval rapid scan Himawari-8 Infrared images (above) showed the well-defined eye as the storm tracked northwestward across the Philippine Sea (just east of the Philippines). A faster animation (GIF | MP4) helped to highlight the trochoidal motion (wobble) of the eye — a behavior often seen with intense tropical cyclones. The 21 UTC advisory from JTWC listed sustained winds of 165 knots (and objective intensity estimates from ADT and SATCON were around 170 knots), making Surigae the only tropical cyclone on record to reach that intensity during the month of April.



An animation of Himawari-8 Infrared images with an overlay of deep-layer wind shear (below) indicated that Surigae was moving through a region of low to moderate wind shear; the storm was also moving across very warm water (SST + OHC).

Himawari-8 Infrared images, with contours of deep-layer wind shear at 18 UTC [click to enlarge]

Himawari-8 Infrared images, with contours of deep-layer wind shear at 18 UTC [click to enlarge]

Around the time that Surigae was reaching its peak intensity, a Suomi NPP VIIRS Day/Night Band (0.7 µm) image several hours before sunrise (below) revealed concentric mesospheric airglow waves (reference) propagating away from the energetic Category 5 tropical cyclone.

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

Suomi NPP VIIRS Day/Night Band (0.7 µm) image [click to enlarge]

In closer view of time-matched Himawari-8 Infrared and Suomi NPP Day/Night Band images (below), a cluster of bright DNB pixels highlighted the presence of lightning activity along the inner edge of the northern eyewall.

Himawari-8 Infrared Window (10.4 µm) and Suomi NPP VIIRS Day/Night Band (0.7 µm) images [click to enlarge]

Himawari-8 Infrared Window (10.4 µm) and Suomi NPP VIIRS Day/Night Band (0.7 µm) images [click to enlarge]

Heavy rainfall and snowfall in Southern California

January 23rd, 2021 |

GOES-17 Air Mass RGB images, with contours of PV1.5 pressure [click to play animation | MP4]

GOES-17 Air Mass RGB images, with contours of PV1.5 pressure [click to play animation | MP4]

As an anomalously-deep 500 hPa low began to move inland over Southern California during the 23 January24 January 2021 period, GOES-17 (GOES-West)  Air Mass RGB images (above) showed a compact Potential Vorticity (PV) anomaly approaching the coast — and the RAP40 model indicated that the “dynamic tropopause” (defined here as the pressure of the PV1.5 surface) was descending to the 675 hPa pressure level at 18 UTC.

A west-to-east oriented cross section of RAP40 model fields along Line A-A’ (below) depicted the descending dynamic tropopause at 19 UTC.

Cross section of RAP40 model fields along line A-A' [click to enlarge]

Cross section of RAP40 model fields along line A-A’ [click to enlarge]

GOES-17 Mid-level Water Vapor (6.9 µm) images (below) showed the increasing reports of rain and snow that resulted as the PV Anomaly moved inland and provided additional forcing for ascent. Near the coast, thunderstorms were reported at Fulton and Long Beach around 03 UTC. Storm total precipitation amounts included rainfall of 1.40 inch and snowfall of 12-18 inches.

GOES-17 Mid-level Water Vapor (6.9 µm) images, with plots of hourly surface weather type [click to play animation | MP4]

GOES-17 Mid-level Water Vapor (6.9 µm) images, with plots of hourly surface weather type [click to play animation | MP4]

GOES-17 Water Vapor images at 2301 UTC and 0246 UTC (below) revealed sporadic lightning activity (indicated by small clusters of GLM Groups).

GOES-17 Mid-level Water Vapor (6.9 µm) image at 2301 UTC, with GLM Groups plotted in red [click to enlarge]

GOES-17 Mid-level Water Vapor (6.9 µm) image at 2301 UTC, with GLM Groups plotted in red [click to enlarge]

GOES-17 Mid-level Water Vapor (6.9 µm) image at 0246 UTC, with GLM Groups plotted in red [click to enlarge]

GOES-17 Mid-level Water Vapor (6.9 µm) image at 0246 UTC, with GLM Groups plotted in red [click to enlarge]

===== 24 January Update =====

GOES-17 Day Snow-Fog RGB images [click t play animation | MP4]

GOES-17 Day Snow-Fog RGB images [click to play animation | MP4]

On the following day, as clouds began to clear the areal extent of resulting fresh snow cover (darker shades of red) was seen in GOES-17 Day Snow-Fog RGB images (above). Even parts of the high desert — north and east of the mountain ranges — received some snowfall (for example, 2-3 inches were reported at Hesperia).

Suomi NPP VIIRS True Color RGB and False Color RGB images (below) showed the snow cover (shades of cyan) at 2036 UTC.

Suomi NPP VIIRS True Color RGB and False Color RGB images [click to enlarge]

Suomi NPP VIIRS True Color RGB and False Color RGB images [click to enlarge]

Tropical Storm Eta over the Gulf of Mexico

November 10th, 2020 |

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images at 0734 UTC [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images at 0734 UTC [click to enlarge]

A toggle between Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images at 0734 UTC (above) showed Tropical Storm Eta over the Gulf of Mexico (northwest of Cuba) on 10 November 2020. A large convective burst was seen southeast of the storm center, with concentric cloud-top gravity waves propagating radially outward from its lightning-illuminated core (intense lightning activity was causing the cluster of bright pixels on the Day/Night Band image).

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm), GLM Flash Extent Density and “Red” Visible (0.64 µm) images (below) showed Tropical Storm Eta from sunrise to sunset, as it continued a slow northward movement — pulsing overshooting tops occasionally exhibited infrared brightness temperatures of -90ºC and colder (yellow pixels embedded within darker shades of purple), and lightning activity persisted for much of the day.

GOES-16 “Clean” Infrared Window (10.35 µm) images (with and without an overlay of GLM Flash Extent Density) and “Red” Visible (0.64 µm) images [click to play MP4 animation]

GOES-16 “Clean” Infrared Window (10.35 µm) images (with and without an overlay of GLM Flash Extent Density) and “Red” Visible (0.64 µm) images [click to play MP4 animation]

===== 11 November Update =====

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm) images [click to play animation | MP4]

Eta once again reached Hurricane intensity at 1235 UTC on 11 November, as it approached the west coast of Florida. 1-minute GOES-16 Visible images (above) showed the partially exposed low-level circulation of Eta; however, it then weakened back to a Tropical Storm several hours later, at 1800 UTC.