A severe thunderstorm developed in Scotts Bluff County and moved southeast into Morrill County the evening of 12 July 2023.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CYS wrote it up.
A severe thunderstorm developed in Scotts Bluff County and moved southeast into Morrill County the evening of 12 July 2023.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Cheyenne, WY wrote its last area forecast discussion before the first event at Jul 12, 4:45 PM MST, 1 hour 2 minutes earlier.
Area Forecast Discussion National Weather Service Cheyenne WY 545 PM MDT Wed Jul 12 2023 .SHORT TERM...(This evening through Friday night) Issued at 330 PM MDT Wed Jul 12 2023 Fairly quiet weather exists this afternoon across most of the area. On the synoptic scale, the quieter weather is related to the strong but shallow ridge whose axis is just to our west. Satellite imagery indicates some shallow, high-based cumulus development over the mountains and starting to spread over southern Wyoming. Surface observations show a fairly sharp dryline straddling the area at this hour, positioned generally from near Pine Bluffs to Wheatland to Douglas. To the west, dewpoints are stuck in the mid 30s around Cheyenne, but quickly climb to the mid 50s by Kimball and Sidney. This feature is positioned a little further west than indicated by earlier model runs, which has resulted in some minor changes to the near term forecast. Modest instability has crept in as far west as Laramie county per RAP analysis, and the latest few HRRR runs are now showing some convection flaring up across Laramie county and the southern panhandle later this evening, between about 02z and 06z. Models indicate some lingering elevated instability and decent shear continuing as the dryline crashes back westward. Therefore, this seemed likely enough to at least warrant introduction of slight chance PoPs for these areas through midnight tonight. Nocturnal convection associated with elevated instability and a very weak vort max traversing overhead may continue through the morning, but should be mainly east of our area. Still can't rule out this activity creeping westward, so maintained low end PoPs for the far eastern counties. However, even if the convection remains off to the east, it could be important for potential wild cards in the forecast for Thursday. We will need to watch for outflow boundaries from the nocturnal/morning convection lingering over portions of the area Thursday morning as they compare to the current model forecasts, since this could alter how Thursday afternoon's storm potential. The challenging aspect of the forecast will be the dryline position. Most models show the dryline setting up fairly close to the CWA boundary by the time convection can get going, but if this ends up just a little bit further west, a favorable storm environment may exist in our area. Most guidance shows substantial instability and steep lapse rates setting up in the morning, but then the advancing dryline cuts this off by mid-afternoon before anything is able to kick up. This could be the kind of day where we may only get one storm, if at all, but if the dryline is further west we may need to look out for severe potential. Otherwise, look for another hot day across the area and breezy conditions along and west of I-25. The strong ridge over the southwest CONUS is expected to retrograde westward on Friday, allowing for more shortwave activity to creep into our area in the northwest flow aloft. This will knock down temperatures a bit especially east of the Laramie range. Look for Friday highs to be about 8-10F cooler than Thursday in these areas. The passing shortwave may also add enough lift to kick off some showers and thunderstorms through the day. However, instability and lapse rates both look modest so the probability of severe weather is fairly low, but nonzero. Precipitation chances may continue into Friday evening or overnight. The GFS, for example, shows the surface front pushing well westward, leading to a region of modest frontogenesis and showers/storms through the evening hours. .LONG TERM...(Saturday through Wednesday) Issued at 330 PM MDT Wed Jul 12 2023 The medium range to extended forecast will include near to slightly above average temperatures, and a couple of upper level disturbances moving along a persisting upper level ridge across our cwa. The northwest flow aloft will provide an opportunity for passing weak wave features to bring chances of showers and isolated thunderstorms to the cwa. As the upper level ridge amplifies across our cwa, we can expect a much warmer trend of temperatures from Sunday to Tuesday before we have a transition to slightly cooler temperatures behind a weak cool frontal passage. Saturday will bring a contrast of CAA to our northern zones due to a passing upper level wave, and WAA for our western zones by the late afternoon ours. The dividing feature between the two air masses will be the Laramie Range. However, with the lower elevations seeing decent atmospheric mixing, daytime maximum temperatures for the eastern forecast zones will be similar to those for areas west of the Laramie Range. The coolest temperatures are likely across the CO/WY border for Saturday as daytime highs there will hover in the middle to upper 70s, with the remainder of the cwa seeing daytime maximums in the low to middle 80s. There will be an isolated chance of thunderstorms on Saturday along the I-80 corridor from Albany County towards the NE Panhandle, but severe weather isn't expected. Sunday and Monday will bring warmer temperatures to our cwa due to the upper level ridge amplifying across the desert Southwest towards the Central and Northern Rockies/Central Plains. The lower and mid- levels of the atmosphere will warm considerably. 700mb temperatures on Sunday will be 5C to 7C warmer than Saturday. This will translate to afternoon highs being 5 to 10 degrees F warmer for Sunday afternoon. Most locations should see middle 80s to lower 90s for highs in the lower terrain, and slightly cooler temperatures in the higher terrain. The axis of the upper level ridge will propagate to the east from the Great Basin area towards the Central/Northern Rockies by Monday. 700mb temperatures by Monday afternoon will range from 15C to 20C, and will mix to the surface easily. Because of the very warm temperatures being present, isolated showers and a thunderstorm may be possible as the elevated mixed layer has weak instability within it. Severe weather is not expected, but afternoon and evening showers and thunderstorms can't be ruled out. Widespread 80s and 90s can be anticipated for the lower terrain to start next week on Monday. Tuesday will be the warmest day of next week. Ensemble members for daytime highs for locations east of the Laramie Range are favoring low to upper 90s. Some cities along the North Platte River Valley from approximately Torrington to Sidney are the highest favored for potentially reaching the century mark for high temperatures. This will be a little tricky to fine tune as we approach Tuesday due to the model guidance favoring an approaching shortwave disturbance to our north. If this shortwave disturbance treks further to the south, then we will see a higher probability of showers and thunderstorms. This could easily impact daytime highs by having additional cloud cover over the area, and slightly cooler temperatures. However, have gone with an aggressive approach to daytime highs, with several areas seeing the highest forecast maximums of the summer period: Widespread 80s and 90s. Have kept the century mark out of the forecast as it is 6 days away at this time of inspection. Wednesday has the signals to be nearly as warm as Tuesday, with isolated chances of showers and thunderstorms as well. We recommend paying attention to the extended forecast as it transitions to the short term desk by early next week. There may be a need to issue headlines due to the very warm to hot temperatures expected by early next week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 537 PM MDT Wed Jul 12 2023 VFR conditions expected across area terminals through the forecast period. The main update to the latest TAFs has been the inclusion of VCTS to KBFF and KAIA early this evening. Latest radar imagery has shown development of a storm near the WY/NE border north of Torrington with hi-res guidance suggesting additional development along a retreating dryline early this evening is possible as well. Moderate rainfall and occasional lightning will be possible if storms move near any terminals, but coverage should remain fairly isolated through 06z. && .FIRE WEATHER... Issued at 330 PM MDT Wed Jul 12 2023 Near critical fire weather conditions continue along and west of the I-25 corridor through Thursday, though fuels remain non- critical which will prevent any fire weather headlines. Still, hot temperatures, low RH, and breezy conditions will return again tomorrow for the same areas. A few isolated thunderstorms are possible over the high plains and could produce locally gusty winds. The dryline is expected to push back westward by Friday, boosting humidity for all except western Carbon county lower elevations. Isolated to scattered thunderstorms are possible Friday and Saturday with cooler temperatures returning. Expect a warming trend to begin Sunday through Tuesday with near critical fire weather conditions possible for areas along and west of I-25. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && SHORT TERM...MN LONG TERM...BW AVIATION...MB FIRE WEATHER...MN
Hazardous Weather Outlook National Weather Service Cheyenne WY 356 PM MDT Wed Jul 12 2023 NEZ002-003-019>021-054-055-095-096-WYZ101>119-132200- Dawes County-Box Butte County-Scotts Bluff County-Banner County- Morrill County-Kimball County-Cheyenne County- Northern Sioux County-Southern Sioux County- Converse County Lower Elevations-Niobrara County- North Laramie Range-Ferris/Seminoe/Shirley Mountains- Shirley Basin-Central Laramie Range and Southwest Platte County- East Platte County-Goshen County-Central Carbon County- North Snowy Range Foothills-Southwest Carbon County- Sierra Madre Range-Upper North Platte River Basin-Snowy Range- Laramie Valley-South Laramie Range-South Laramie Range Foothills- Central Laramie County-East Laramie County- 356 PM MDT Wed Jul 12 2023 This hazardous weather outlook is for portions of panhandle Nebraska...east central Wyoming...south central Wyoming and southeast Wyoming. .DAY ONE...THIS AFTERNOON AND TONIGHT A few isolated storms are possible across far southeast Wyoming and the southern Nebraska panhandle tonight. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY A few isolated thunderstorms are possible in the Nebraska panhandle Thursday, and could become strong to severe. Isolated to scattered thunderstorms are possible Friday and Saturday. .Spotter information statement... Spotter activation will not be needed.
The Cheyenne radar (KCYS), 142 km away, was scanning. The volume nearest the first event began at 00:44 UTC.
4 hail. Local standard time, as filed.
Emergency Manager first reported 2.0 inch hail 8 miles north northeast of Minatare. Lasted 5 minutes.
Twitter report of 1.5 inch hail 5 miles north of Bridgeport.
Twitter report of 1.5 inch hail.
Public report of 1.75 inch hail 7 miles south of Angora.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Nebraska in 2023Every state in 2023This day in weather historyWarnings in Nebraska, July 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1100396, 1100397, 1103516, 1103517.