Due to an overlap of GOES-17 (GOES-West) Mesoscale Domain Sectors, images were available at 30-second intervals — and “Red” Visible (0.64 µm) images (above) showed the development of thunderstorms over southeastern Oregon, southwestern Idaho and northern Nevada on 29 May 2019. Some of these thunderstorms produced heavy rainfall and small hail in southwestern Idaho, and a cold air funnel was spotted in northern Nevada (local storm reports).

A comparison of Visible images from GOES-17 and GOES-15 images (below) helps to underscore some of the improvements in the GOES-R series of satellites over their predecessors — with images every 30 seconds compared to every 4-15 minutes (with gaps of 30 minutes during the Full Disk scans every 3 hours), the short-term convective trends could be better monitored using GOES-17. Also note that the GOES-15 Visible images do not appear as bright as those from GOES-17 — prior to the GOES-R Series of satellites, the performance of visible detectors degraded over time, leading to imagery that appeared more dim as the Imager instrument aged. Visible detectors on the new ABI instrument benefit from on-orbit calibration to remedy this type of degradation.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) depicted supercell thunderstorms forming along and south of a quasistationary frontal boundary (surface analyses) which produced a variety of severe weather (SPC Storm Reports) across eastern Kansas and far western Missouri late in the day on 28 May 2019 — including the long-track EF-4 tornado that affected Lawrence and Linwood in Kansas (NWS Kansas City), and prompted a Tornado Emergency to be issued for the Kansas City metro area.

The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images (below) showed that many of the overshooting tops had infrared brightness temperatures in the -70 to -75ºC range.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) revealed supercell thunderstorms that developed within the warm sector of a midlatitude cyclone approaching from the Upper Midwest (surface analyses) — these thunderstorms produced a variety of severe weather (SPC Storm Reports | NWS Northern Indiana) across Indiana late in the day on 27 May 2019.

Many of these storms exhibited well-defined overshooting tops; the largest hail was 4.0 inches in diameter at 0000 UTC. A comparison of SPC Storm Reports at the time of this large hail (and a nearby wind gust to 72 mph) — plotting the reports at the actual ground location vs a “parallax-corrected” location which shifted them northwestward — showed that the severe report locations closely corresponded to the overshooting top (below).

The corresponding GOES-16 “Clean” Infrared Window (10.35 µm) images (below) showed that many of the overshooting tops had infrared brightness temperatures in the -70 to -75ºC range.

As the thunderstorms moved eastward across Ohio, they continued to produce all modes of severe weather (including EF-3 and EF-4 tornadoes in the Dayton area beginning around 0258 UTC). Additional information on these storms is available from the Hazardous Weather Testbed.

A Terra MODIS Infrared Window (11.0 µm) image at 0243 UTC with plots of SPC Storm Reports within +/- 45 minutes of the image time (below) showed cloud-top infrared brightness temperatures as cold as -73ºC.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Clean” Infrared Window (10.35 µm) images (above) showed squall line thunderstorms which produced tornadoes, large hail and damaging winds (SPC Storm Reports) across Oklahoma on the evening of 25 May 2019. Of significance was the EF-3 tornado that affected El Reno, Oklahoma which was responsible for 2 fatalities (NWS Norman).

The GOES-16 Infrared imagery revealed evidence of pulsing updrafts (clusters of colder, brighter white pixels) to the northwest of El Reno (KRQO) — between Watonga (KJWG) and Weatherford (KOJA) — that began at 0248 UTC. 1-minute Infrared brightness temperatures associated with the bowing segment then fluctuated between -73.3ºC and -76.3ºC during the subsequent 40 minutes leading up to the El Reno tornado at 0328 UTC (below). Correcting for parallax, this would have moved those pulsing updrafts southeastward, closer to KRQO.

One way of illustrating the magnitude of the GOES-16 parallax shift is to compare SPC Storm Reports at the time of the El Reno tornado — plotting the reports at the actual ground location vs a “parallax-corrected” location which shifts them northwestward to more closely correspond to the 13-km mean height of the storm-top Infrared features (below). Note that the parallax-corrected El Reno tornado report location is nearly coincident with that of a colder (lighter shade of white) overshooting top.

About an hour after the El Reno tornado, a Terra MODIS Infrared Window (11.0 µm) image (below) displayed cloud-top infrared brightness temperatures as cold as -73ºC as the thunderstorms moved eastward and spread severe weather into the Tulsa area.

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