1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed thunderstorms that produced several tornadoes, hail up to 4.50 inches in diameter and wind gusts to 73 mph (SPC Storm Reports) in addition to heavy rainfall across parts of central and eastern Nebraska (NWS Omaha summary) on 12 May 2023.

Pulsing thunderstorm overshooting tops exhibited infrared brightness temperature values as cold as -75.5ºC and multispectral Cloud Top Temperature values as cold as -77ºC — according to a plot of 0000 UTC rawinsonde data from Omaha, Nebraska (source) shown below, those temperatures correspond to an overshoot of the Most Unstable air parcel Equilibrium Level (MU EL) of about 1 km.

1-minute GOES-16 Infrared images (below) include an overlay of GLM Flash Extent Density — a notable lightning jump was evident in association with a large, destructive and long-lived tornado that moved north of Fremont, Nebraska (station identifier KFET) from about 2238-2338 UTC (cursor readout of Local Storm Reports at 2238 UTC | 2254 UTC | 2303 UTC | 2305 UTC | 2317 UTC | 2323 UTC | 2336 UTC), with frequent Flash Extent Density values in the 140-145 flashes/5-minutes range (darker shades of red).

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The storm system named ‘Mocha’ is brewing in the Bay of Bengal and was upgraded to tropical storm status earlier today. Mocha began as a deep depression in in the southeast Bay of Bengal. It is forecasted to continue moving north and gain strength, predicted to become a typhoon within 24 hours. Mocha’s current wind speeds are 50 mph.

Mocha will likely make landfall near the border between Myanmar and Bangladesh on Sunday, May 14. By that time, it will be upgraded to a ‘cyclonic storm’, or typhoon. It is predicted to cause winds up to 80 mph. Andaman and Nicobar Islands are already experiencing heavy rains from the system. Mocha will trigger heavy rains over north east India on Saturday and Sunday, as it approaches and makes landfall.

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1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed thunderstorms that produced several tornadoes, hail up to 4.00 inches in diameter, wind gusts to 81 mph and heavy rainfall (SPC Storm Reports) across northeast Colorado, northwest Kansas and southwest Nebraska on 10 May 2023.

1-minute GOES-16 Infrared images (below) include an overlay of GLM Flash Extent Density — most of the storms exhibited only modest lightning activity, although a few brief lightning jumps were evident.

GOES-16 Visible/Infrared Sandwich RGB images at 2213 UTC and 2218 UTC (below) include a cursor sampling of the associated Rainfall Rate (red), Cloud Top Phase (yellow) and Cloud Top Height (green) Level 2 Derived Products over the location of Local Storm Reports of Heavy Rainfall and Flash Flooding in northwest Kansas. As discussed in this TOWR-S Satellite Book Club presentation, beginning with TOWR-S RPM 22 various types of “GOES RGBs w/Derived Product Readouts” are available in AWIPS under Satellite -> Local Menu Items, which includes these options.

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Cincinnati’s 25th running of the Flying Pig Marathon commenced on the morning of Sunday, May 7th, despite deteriorating weather conditions. After a round of storms at about 09:30 UTC, which subsequently passed through, race officials began the marathon as scheduled at 10:30 UTC. Figure 1 shows the composite reflectivity and LightningCast contours 0-30 minutes prior to the start time. The point marked “H” in the center of the animations below is the Cincinnati Municipal Airport — Lunken Field, which is about 3 miles east of downtown Cincinnati, where the marathon took place. In Figure 1, we see some storm cells intensifying and heading east toward downtown Cincinnati. The LightingCast probability of lighting in the next hour was > 50% at 10:30 UTC, when the race began.

ProbSevere LightningCast uses artificial intelligence and GOES-R ABI data to predict the probability of lightning in the next 60 minutes, as observed by the GOES-R Geostationary Lightning Mapper (GLM). Figures 2 and 3 show animations of LightningCast probabilities with GOES-16 10.3 µm brightness temperature and GLM flash-extent density (Figure 3). As the convection approaches downtown Cincinnati, we see cooling cloud tops and intensifying lightning flash rates. Furthermore, in Figure 3, we see a number of anvil flashes “overhead” of point H (i.e., within the GLM pixel containing point H) just prior to the start of the race. With thick ice from the anvil of the departing round of storms and the anvil of the approaching line of storms, LightningCast probabilities remained high despite no flash centroids within 10 miles of downtown Cincinnati during the inter-storm period (~10:15 to 11:00 UTC).

Using the LightningCast time series capability at Cincinnati Municipal Airport — Lunken Field (Figure 4), we see that the probability of lightning remained elevated (40-60%) in the inter-storm period, then jumped up to 71% by 10:36 UTC. The probability steadily increased to 96% at 10:51 UTC, 28 minutes before a shelter-in-place order was issued to runners. The “order” was more of a recommendation, according to race officials, as many runners were either confused by it or ignored it. The race began at 10:30 UTC, which was 15 minutes after the last flashes (within 10 miles) from the first round of storms.

Fortunately, there were no reported lightning-related injuries to racers or spectators, despite dozens of observed flashes every 5 minutes, within 5 miles of downtown Cincinnati. We aim to make LightningCast usable by forecasters and event managers to help make informed decisions such as postponements and sheltering at events with high vulnerability to lightning.

h/t to Kevin Thiel for providing information for this event.

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