Severe weather across southern Wisconsin

May 9th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.3 µm, bottom) images, with airport identifiers plotted in yellow and SPC storm reports plotted in red [click to play MP4 animation]

Severe weather (SPC | NWS ARX | NWS MKX) occurred across far southern Wisconsin on the afternoon of 09 May 2018, as a surface low moved eastward across the area. 1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) provided a view of the isolated thunderstorm that rapidly developed in far southwestern Wisconsin around 1800 UTC. The evolution of overshooting tops was seen in both Visible and Infrared imagery — cloud-top infrared brightness temperatures cooled into the -50 to -60 ºC range (orange to red enhancement). On the Visible imagery, rear inflow feeder bands could be seen on the southwestern flank of the storm leading up to the time that it produced 1.00-inch diameter hail near Madison at 2045 UTC. SPC storm reports are “parallax corrected” so as to be plotted at a height corresponding to the cloud-top features of the parent storm.

A comparison of Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images at 1923 UTC (below) showed the isolated thunderstorm as it was moving into northwestern Dane County. The rear inflow feeder bands were evident, and the minimum cloud-top infrared brightness temperature was -62 ºC.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images [click to enlarge]

GOES-16 Rayleigh-corrected pseudo true color Red-Green-Blue (RGB) images (below; courtesy of Pete Pokrandt, AOS) showed a large Mesoscale Convective Vortex (MCV) that moved through northern Illinois and Wisconsin during the early morning hours, along with the hazy signature of smoke from agricultural burning in the central Plains (which was being drawn northward across eastern Iowa ahead of the surface cold front).

GOES-16 Rayleigh-corrected RGB images [click to play YouTube video]

GOES-16 Rayleigh-corrected RGB images [click to play YouTube video]

Severe weather in Kansas, Nebraska and Iowa

May 1st, 2018 |

GOES-16

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

Severe thunderstorms produced tornadoes, large hail and damaging winds across parts of Kansas, Nebraska and Iowa on 01 May 2018. A Mesoscale Domain Sector  provided images at 1-minute intervals — SPC storm reports are plotted on 0.64 µm “Red” Visible images (above) and 10.3 µm “Clean” Infrared Window images (below).

GOES-16

GOES-16 “Clean” Infrared Window (10.3 µm) images, with SPC storm reports plotted in cyan [click to play MP4 animation]

Many of the storms exhibited cloud-top signatures commonly associated with severe weather — for example, pronounced “enhanced-v” signatures with “cold/warm thermal couplets” were seen on Infrared imagery with the tornado-producing storms in northern Kansas and southern Nebraska (below), and both a well-defined “overshooting top” and an “above-anvil plume” were seen on Visible imagery with the Nebraska storm.

GOES-16

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images, with SPC storm reports [click to enlarge]

Severe thunderstorms in South Florida

April 10th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.3 µm, bottom) images, with SPC storm reports plotted in red and airport identifiers plotted in yellow [click to play MP4 animation]

1-minute Mesoscale Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the southward propagation of a pre-cold-frontal trough axis (surface analyses) which appeared to play a role in enhancing ongoing convection — some thunderstorms then produced weak tornadoes, damaging winds and hail over parts of South Florida during the afternoon hours on 10 April 2018 (KMFL PNS). SPC storm reports are plotted on the GOES-16 images.

The NOAA/CIMSS ProbSevere All Hazards product (from this site) for the 1934 UTC tornado is shown below, at two-minute intervals from 1926-1946 UTC. ProbWind for this storm jumped as the tornado began, and the storm had the highest ProbWind values of those on the map.

NOAA/CIMSS ProbSevere All Hazards read-out from 1926-1946 UTC on 10 April 2018 (Click to enlarge)

The NOAA/CIMSS ProbSevere All Hazards product (from this site) for the 2025 UTC tornado is shown below, at two-minute intervals from 2012-2034 UTC. ProbTor increased from 1% to 10% between 2020 UTC and 2028 UTC with this storm.  ProbWind exceeded 90%.

NOAA/CIMSS ProbSevere All Hazards read-out from 2012-2034 UTC on 10 April 2018 (Click to enlarge)

Gravity Waves forced by an isolated thunderstorm in the Gulf of Mexico

April 9th, 2018 |

GOES-16 ABI Upper-Level Water Vapor (6.2 µm) Infrared Imagery, 1352-1857 UTC on 9 April 2018 (Click to animate)

Upper-level Water Vapor (6.2 µm) infrared imagery on 9 April 2018 (above) revealed gravity waves propagating away from an isolated thunderstorm in the Gulf of Mexico.

The convective complex generated gravity waves that were visible in all 3 GOES-16 ABI Water Vapor Channels (6.19 µm, 6.95 µm and 7.34 µm).  The image below (produced using SIFT, the Satellite Information Familiarization Tool and data from NOAA CLASS) shows all three channels at 1812 UTC;  the color enhancement used is the same in each image, but the ranges were modified to make the gravity waves most visible.  Ranges used were -109 to 34 º C (Band 8); -109 to 55 º C (Band 9) and -80 to 42 º C (Band 10).

Weighting functions for the three water vapor infrared channels for three stations surrounding the Gulf of Mexico (Slidell, LA; Tallahassee FL; Tampa FL) suggest the gravity waves were in the 300-450 mb layer (6.2 µm) to the 450-600 mb layer (7.3 µm).

GOES-16 ABI Water Vapor Infrared Imagery at 1812 UTC on 9 April 2018: Upper Level (left), Mid-Level (center), Low-Level (right) (Click to enlarge)