Severe thunderstorms produced very large hail and damaging winds across portions of Osborne, Jewell, and Mitchell counties late on this Saturday afternoon. Between 2 and 3 PM CST, the first couple storms began forming south and southwest of Hill City.
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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 GID wrote it up.
Severe thunderstorms produced very large hail and damaging winds across portions of Osborne, Jewell, and Mitchell counties late on this Saturday afternoon. Between 2 and 3 PM CST, the first couple storms began forming south and southwest of Hill City. Around 330 PM CST, one storm moved into southwestern Rooks county. It was joined by several other storms which continued to develop along I-70 between Wakeeney and Russell. As the Rooks county storm moved east, these storms moved north and they all merged over Osborne county. Just prior to the merger, a left-moving supercell, fresh after the split, produced hail up to the size of tennis balls near the southern border of Osborne county. After the merger, the newly-formed multicell cluster took the form of a small bow echo as it moved across Mitchell county between 5 and 6 PM CST. The mesoscale convective system produced strong downburst winds that were estimated at 60 mph over central Osborne county and measured at 66 mph over Mitchell county, just west of Beloit. While this was occurring, other cells formed over Jewell county and became severe. Before merging, the southern storm produced a measured wind gust of 78 mph in the town of Jewell, while the northern one produced spotty wind damage from the town of Mankato to Lovewell Reservoir. Tree limbs were snapped off in Mankato, at least one power pole was snapped off northeast of town, and an old county communications building suffered damage as the powerful downburst winds blew the roof off. Rain then damaged the radio equipment housed inside.
These storms formed along and ahead of a Canadian cold front. The flow aloft was west-southwest from Arizona to Maine and it was low in amplitude. A shortwave trough was along the New Mexico-Texas border and lifting northeast. Before the thunderstorms moved in, temperatures were near 90 with dewpoints in the middle to upper 60s. Mid-level lapse rates were near 7.0 C/km. This resulted in MLCAPE around 2000 J/kg. Deep layer shear was around 40 kt.
This event was one of several episodes of heavy convective rains that contributed to a very wet start to September. This event alone produced 3 to 4 inch rain amounts over parts of Osborne and Mitchell counties as scattered non-severe storms continued to develop through the night, after the severe storms had exited north central Kansas. Four-day rainfall totals ending on the morning of the 5th ranged from 3 to 6 inches over Osborne, Mitchell, and Jewell counties. The highest rainfall amounts included 6.55 at Cawker City, 5.98 at Jewell, 5.22 at Beloit, and 5.20 at Osborne.
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 Hastings, NE wrote its last area forecast discussion before the first event at Sep 1, 5:31 AM CST, 29 minutes earlier.
Area Forecast Discussion National Weather Service Hastings NE 631 AM CDT Sat Sep 1 2018 .SHORT TERM...(Today and tonight) Issued at 351 AM CDT Sat Sep 1 2018 A few thunderstorms have been moving through the forecast area early this morning. Behind the thunderstorms, there are a few showers. A boundary has moved to the south through the area and for a time behind the boundary, the winds are from the north, then they turn back to the south or southeast. Once the current thunderstorms move out of the area, expect the showers to push through and there should be a break for a while during the day. There will be an upper level wave that moves through the area today. The models have little differences in the timing of the wave and the precipitation. Have kept some low PoPs through the morning and into the afternoon before increasing the chance for precipitation. Most of the models have some precipitation around the area during the day, but later this afternoon, most have the precipitation in the central to southeast part of the forecast area. The models are more consistent during the evening and overnight hours with a good chance for precipitation for much of the area. The only concern is that a couple of the models have the precipitation coming to an end late tonight. Have kept higher PoPs, but did lower some in the northwest. As for severe weather, the CAPE is best in the east and southeast and the southeast is the area with best shear during the afternoon. By evening and overnight, the CAPE decreases pretty quickly. .LONG TERM...(Sunday through Friday) Issued at 351 AM CDT Sat Sep 1 2018 Another wave moves through the area Sunday and Sunday night. Expect there to be showers and thunderstorms around the area through this period. There could be a little severe weather mainly in the southeast, but the CAPE and the shear are not as strong as they are for today. The main concern for this time frame is there could be some heavier rain and after some rain today will need to watch for localized flooding. With an upper level trough in the western CONUS, the southwest flow continues for Monday through Tuesday night. There will not be rain continuously through the period, but there will be on and off showers and thunderstorms. There is still the potential for some fairly decent rainfall through the period. At this time, the best break in the rain will be on Wednesday. There is a surface high that tries to build into the area. Have brought an end to the precipitation in the northwest, but there is still some small PoPs in the south and east. There is still plenty of low level moisture and there will be cloudy skies. By Thursday there is some precipitation around the area again, but this time it looks more light and have kept PoPs lower. Thursday night into Friday there is another weak wave that moves through the area and there will be another chance for some showers and thunderstorms. && .AVIATION...(For the 12Z KGRI/KEAR TAFS through 12Z Sunday) Issued at 627 AM CDT Sat Sep 1 2018 Thunderstorms are possible mainly this afternoon and evening. There could be a few thunderstorms during the morning, but the chances are small. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && SHORT TERM...JCB LONG TERM...JCB AVIATION...JCB
Hazardous Weather Outlook National Weather Service Hastings NE 524 AM CDT Sat Sep 1 2018 KSZ005>007-017>019-NEZ039>041-046>049-060>064-072>077-082>087- 021200- Phillips-Smith-Jewell-Rooks-Osborne-Mitchell-Valley-Greeley-Nance- Sherman-Howard-Merrick-Polk-Dawson-Buffalo-Hall-Hamilton-York- Gosper-Phelps-Kearney-Adams-Clay-Fillmore-Furnas-Harlan-Franklin- Webster-Nuckolls-Thayer- 524 AM CDT Sat Sep 1 2018 This Hazardous Weather Outlook is for south central Nebraska and portions of north central Kansas. .DAY ONE...Today and Tonight. Thunderstorms are possible today and tonight. Strong to severe thunderstorms are possible mainly this afternoon and evening. The primary threats will be hail to the size of ping pong balls, wind gusts to 60 mph and heavy rainfall. .DAYS TWO THROUGH SEVEN...Sunday through Friday. This looks to be a fairly active weather pattern, with at least small chances for thunderstorms each day and night. There is a chance for strong to severe thunderstorms Sunday afternoon and evening to the southeast of a line from Fullerton NE to Stockton KS. The primary threats will be large hail, damaging winds and heavy rainfall. Heavy rainfall is possible on Monday as well. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon and evening. && More information may be obtained at the following web page: https://www.weather.gov/hastings
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HASTINGS NE
215 AM CDT SAT SEP 1 2018
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0154 AM TSTM WND GST 4 SSW ALDA 40.81N 98.50W
09/01/2018 M52 MPH HALL NE MESONET
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SRPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HASTINGS NE
229 AM CDT SAT SEP 1 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
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0224 AM TSTM WND GST 3 W BRADSHAW 40.88N 97.81W
09/01/2018 M57 MPH YORK NE MESONET
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SRPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HASTINGS NE
230 AM CDT SAT SEP 1 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
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0224 AM TSTM WND GST 3 SSE BRADSHAW 40.84N 97.73W
09/01/2018 M51 MPH YORK NE MESONET
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SRSpecial Weather Statement National Weather Service Hastings NE 232 AM CDT SAT SEP 1 2018 NEZ049-063-064-010815- Hamilton NE-York NE-Polk NE- 232 AM CDT SAT SEP 1 2018 ...SIGNIFICANT WEATHER ADVISORY FOR YORK...EAST CENTRAL HAMILTON AND POLK COUNTIES UNTIL 315 AM CDT... At 232 AM CDT, Doppler radar was tracking strong thunderstorms along a line extending from near Hordville to near Polk to Bradshaw. Movement was northeast at 25 mph. Wind gusts up to 50 mph will be possible with these storms. Locations impacted include... York, Stromsburg, Henderson, Osceola, Shelby, Polk, Bradshaw, Waco, Benedict, Gresham and Thayer. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with these storms, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 4078 9784 4103 9791 4139 9737 4078 9737 TIME...MOT...LOC 0732Z 224DEG 23KT 4106 9794 4099 9780 4088 9775 Rossi
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HASTINGS NE
233 AM CDT SAT SEP 1 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
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0215 AM TSTM WND GST AURORA AIRPORT 40.89N 97.99W
09/01/2018 M51 MPH HAMILTON NE AWOS
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SRPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HASTINGS NE
244 AM CDT SAT SEP 1 2018
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0235 AM TSTM WND GST YORK AIRPORT 40.89N 97.62W
09/01/2018 M52 MPH YORK NE AWOS
&&
SRThe Grand Island radar (KUEX), 89 km away, was scanning. The volume nearest the first event began at 11:57 UTC.
4 thunderstorm wind, 2 heavy rain, 2 hail. Local standard time, as filed.
A 24 hour rainfall total of 4.10 inches was reported, with the brunt of the rain falling between 5 PM CDT on the 1st and 4 AM CDT on the 2nd.
A 24 hour rainfall total of 3.41 inches was reported, with the brunt of the rain falling between 5 PM CDT on the 1st and 4 AM CDT on the 2nd. A total of 3.30 inches was also reported near Covert.
Hail ranging in size from quarters to tennis balls was reported.
Wind gusts were estimated to be near 60 MPH.
Wind gusts estimated to be near 70 MPH resulted in tree limbs being downed in Mankato and a power pole being snapped near Montrose. In the Lovewell State Park area, a roof of an old radio communications building was torn off and nearby crops were damaged.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Kansas in 2018Every state in 2018This day in weather historyWarnings in Kansas, September 2018
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: 778080, 778081, 778040, 778045, 778042, 778039, 778046, 778047.