* The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. *

A significant outbreak of severe thunderstorms developed on 16 May 2017, producing damaging winds, large hail and tornadoes from Texas to Wisconsin (SPC storm reports). On the northern end of this outbreak, hail as large as 3.0 inches in diameter fell in northwestern Wisconsin, and a long-track tornado resulted in 1 fatality and 25 injuries near Chetek (NWS Twin Cities MN summary). GOES-16 Visible (0.64 µm) and Infrared Window (10.3 µm) images (above) showed the development of the convective systems; surface-to-cloud-top parallax-corrected SPC storm reports are plotted on the images. Overshooting tops and above-anvil cloud plumes were evident on the visible images, with well-defined “enhanced-V” and “cold/warm thermal couplet” storm top signatures seen on the infrared imagery.

A closer view of the GOES-16 Visible and Infrared Window images (below) provided more detail of the supercell storm-top structure. Note that the pronounced infrared enhanced-V signature began to develop near the Minnesota/Wisconsin border just before 2100 UTC, which was about 40 minutes prior to the first Wisconsin hail report of 2.5 inches and the beginning of the long-track tornado. Since the early 1980s (reference), the enhanced-V satellite signature has been recognized as a reliable predictor of supercell thunderstorms having a high potential to produce either damaging winds, large hail or tornadoes; an automated Enhanced-V / Overshooting Top product (reference) will be available using the ABI instrument on the GOES-R series of satellites..

A comparison of GOES-13 (GOES-East) and GOES-16 Infrared Window images (below) demonstrated the advantage of improved spatial resolution (2-km at satellite sub-point with GOES-16, vs 4-km with GOES-13) for identifying features such as cold overshooting tops.

True-color Red/Green/Blue (RGB) imagery (below; courtesy of Kaba Bah, CIMSS) offered another view of the storms on a regional scale.

 

First WI #tornado death Tue. since Aug. 19, 2011 near Chetek, WI. #Damage survey today. (Photo: Kevin Vroman; Rotation track: NWS) #wiwx pic.twitter.com/BqpyldBh6M

— Jonathan Erdman (@wxjerdman) May 17, 2017

A time series of the the NOAA/CIMSS ProbTor product and its ingredients, below, showed large values of ProbTor (forced especially, perhaps, by large values of Azimuthal Shear).  Storm Reports from SPC show a tornado time near Chetek of 2235 UTC

An animation of NOAA/CIMSS ProbSevere, below, from 2100 through 2310 UTC, shows the radar-defined objects, including an annotated one that was associated with the Chetek tornado (for which the time series is displayed above).  That object crosses the St. Croix River from Minnesota into Wisconsin at 2100 UTC, subsequently moving over Turtle Lake and Barron, and ending up, at 2310 UTC (the end of the animation) near Ladysmith.  It was the sole radar object with a ProbTor that exceeded 20% — with one exception.  At 2220 and 2230 UTC the radar object just to the west of the Chetek tornado radar object had ProbTor values of 20% and 26%, respectively. (Click here for an unannotated animation).

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** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **

East Pacific Ocean Tropical Depression 1E intensified to become Tropical Storm Adrian (at 9.5º N latitude, 92.3º W longitude) at 03 UTC on 10 May 2017 — making it the earliest tropical storm on record in the East Pacific basin during the meteorological satellite era. GOES-16 Infrared Window (10.3 µm) images (above) revealed a series of nocturnal convective bursts which exhibited cloud-top infrared brightness temperatures in the -80º to -89º C range (shades of violet color enhancement).

During the subsequent daylight hours, GOES-16 Visible (0.64 µm) images (below) showed that southeasterly deep layer wind shear (source) had decoupled the organized convection from the exposed low-level circulation center (LLCC). Due to the far southern location of Adrian, only Full Disk scan images were available, at 15-minute intervals.

However, one of the GOES-16 Mesoscale Sectors was positioned over Adrian during the 2226-2355 UTC period, providing images of the LLCC at 1-minute intervals (below).

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** The GOES-16 data posted on this page are preliminary, non-operational data and are undergoing testing. **

Severe thunderstorms developed over eastern Colorado on 08 May 2017, producing large hail (especially in the Denver area: SPC storm reports | NWS Boulder summary). Both GOES-16 Mesoscale Sectors were positioned over that region, providing 30-second interval images — Visible (0.64 µm) and Infrared Window (10.35 µm) images (above) showed the convection in great detail, with SPC storm reports of hail size (inches; H275 = 2.75 inches in diameter) plotted in red/cyan. Several of the storms exhibited well-defined overshooting tops in the Visible imagery, as well as “enhanced-V” and/or cold-warm “thermal couplet” signatures on the Infrared imagery.

#GOES16 30-sec visible texture (blue (red) lines, weak (strong) overshooting) and IR cold spot (magenta) detects strong CO storms on 8 May pic.twitter.com/ApGrC0NLNH

— Kris Bedka (@krisbedka) May 11, 2017

A comparison of 30-second interval GOES-16 Mesoscale Sector and 15-minute interval GOES-13 (GOES-East) Routine Scan visible images (below) demonstrated the clear advantage of rapid-scan imagery for monitoring convective development. Also note the degradation of GOES-13 visible imagery (the cloud features do not appear as bright), due to the age of that satellite — the GOES-R series ABI instrument features on-board visible detector calibration, so this type of visible image degradation over time will not occur.

Suomi NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images (below; actual satellite overpass time 1943 UTC) provided a high-resolution (375 meter) view of the developing thunderstorms, about 17 minutes before the first report of hail northeast of Trinidad (KTAD) at 2000 UTC — a number of these storms exhibited cloud-top infrared brightness temperatures of -70 to -73º C (black enhancement). The VIIRS instrument will also be on the JPSS series of satellites, the first of which is scheduled to be launched in the 4th quarter of 2017.

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Cyclone Donna (18P) formed in the South Pacific Ocean (northeast of Vanuatu) on 02 May 2017. Himawari-8 Infrared Window (10.4 µm) images during the 03-06 May period (above) revealed the formation of multiple convective bursts, many exhibiting cloud-top IR brightness temperatures of -90º C and colder.

On 07 May, Cyclone Donna rapidly intensified from a Category 2 to a Category 4 storm (SATCON | ADT) — and Himawari-8 Infrared Window images (below) showed the presence of a large eye for a few hours. Environmental factors favoring rapid intensification included warm sea surface temperatures and light vertical wind shear.

A comparison of GMI Microwave (85 GHz) and Himawari-8 Infrared Window (10.4 µm) images from the CIMSS Tropical Cyclones site (below) showed that the actual diameter of the eye was much larger on microwave imagery around 1400 UTC on 07 May.

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