Supercell thunderstorms developed late morning on 7/11 and produced up to grapefruit sized hail.
Every event with a place to put it. Tap one for its entry below.
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 TOP wrote it up.
Supercell thunderstorms developed late morning on 7/11 and produced up to grapefruit sized hail.
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 Topeka, KS wrote its last area forecast discussion before the first event at Jul 11, 11:50 AM CST, 10 minutes earlier.
Area Forecast Discussion National Weather Service Topeka KS 1250 PM CDT Sat Jul 11 2020 .SYNOPSIS... Issued at 257 AM CDT Sat Jul 11 2020 A subtle shortwave was seen in the 07Z water vapor imagery moving across eastern NEB. Meanwhile an upper ridge remained centered over NM and the southwestern U.S. and the mean westerlies remained over the northern tier of the country. At the surface, a mesoscale high pressure system associated with convection was building into southeast NEB and an outflow boundary has moved into north central KS. && ...Update to aviation forecast discussion... .SHORT TERM...(Today and tonight) Issued at 257 AM CDT Sat Jul 11 2020 Convective allowing models have been trending dryer with convection over the forecast area this morning. It appears from the 00Z TOP RAOB that an elevated mixed layer has advected over the forecast area with 700MB temps warming to around +12C. This has increased the convective inhibition for surface based parcels. And profiler data show a weak low level jet already veering to the southwest. This limited convergence and moisture transport along with the CIN is probably the cause for the weakening of the MCS as it moves southeast. So the question becomes how does this affect the forecast for the rest of the day? Models in general are slower with the progression of a synoptic scale front and there is still a fairly moist boundary layer over the region with models progs of MUCAPE between 4000 and 5000 J/kg. Forecast soundings still show warm air at 700MB with possibly some slight cooling through the day. With an outflow or frontal boundary in the area, there could be some redevelopment in the afternoon. So have held onto some chance POPs across east central KS through the afternoon. Deep layer shear is sufficient for organized updrafts. So with the very unstable airmass expected, there could be some severe storms with large hail and damaging downdrafts. Highs today are expected to be similar to yesterday since there isn't a big change in airmass. Although convection could throw a wrench into the forecast if it develops early in the afternoon. The cold front should eventually push through this evening bringing an end to precip chances and lows in the 60s. .LONG TERM...(Sunday through Friday) Issued at 257 AM CDT Sat Jul 11 2020 Models continue to show the pattern flattening out through the middle of next week. This could allow for some weak perturbations to move across northern KS while a frontal boundary slides south into the forecast area. As a result there are small chances for precip spread out through the forecast beginning Monday night. Confidence in these POPs is below average since the waves are relatively small scale. The ECMWF continues to show the mid level ridge reamplifying over the central plains by Friday and it brings in some hot air as a result. The other models are not as strong with the ridge and are not quite as hot. So have kept highs in the mid and upper 90s for Friday. But spread among the NBM members shows highs around 100 are not out of the realm of possibility. && .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) Issued at 1242 PM CDT Sat Jul 11 2020 Storms continue to fire north of the terminals associated with an area of convergence. These storms are the main aviation concerns within this forecast period. Currently, still have VCTS for the storm mention as they should remain isolated to scattered. Updates will be made soon if these storms will track more directly into the TOP/FOE terminals which appear to be the most likely sites to be directly impacted over the next 2 to 4 hours. KMHK is less likely to see impacts but could still see storms, so have left mention of VCTS at this time. All of this activity is expected to push south of the terminals by 23Z and winds remain northerly into the overnight period as the boundary passes to the south. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && SYNOPSIS...Wolters SHORT TERM...Wolters LONG TERM...Wolters AVIATION...Drake
Hazardous Weather Outlook National Weather Service Topeka KS 924 AM CDT Sat Jul 11 2020 KSZ008>012-020>024-026-034>040-054>056-058-059-121430- Republic-Washington-Marshall-Nemaha-Brown-Cloud-Clay-Riley- Pottawatomie-Jackson-Jefferson-Ottawa-Dickinson-Geary-Morris- Wabaunsee-Shawnee-Douglas-Lyon-Osage-Franklin-Coffey-Anderson- 924 AM CDT Sat Jul 11 2020 This hazardous weather outlook is for east central...north central and northeast Kansas. .DAY ONE...Today and Tonight. Scattered strong to severe thunderstorms may develop this afternoon anywhere across northeast and east central Kansas. Some of these storms could produce large hail and damaging winds. An isolated tornado cannot be ruled out. .DAYS TWO THROUGH SEVEN...Sunday through Friday. There is some potential for an extended period of hot weather by the end of next week. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed through tonight. && More detailed information can be accessed at... http://www.weather.gov/top/sitrep
Special Weather Statement
National Weather Service Topeka KS
1132 AM CDT Sat Jul 11 2020
KSZ009-010-111700-
Washington-Marshall-
1132 AM CDT Sat Jul 11 2020
...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN WASHINGTON AND
NORTHWESTERN MARSHALL COUNTIES UNTIL NOON CDT...
At 1130 AM CDT, Doppler radar was tracking a strong thunderstorm 4
miles southeast of Hollenberg, moving southeast at 25 mph.
Pea size hail and wind gusts up to 50 mph will be possible with this
storm.
Locations impacted include...
Hanover, Hollenberg and Bremen.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 3990 9657 3973 9690 3993 9713 4000 9701
4000 9685
TIME...MOT...LOC 1630Z 309DEG 21KT 3993 9695
JPSpecial Weather Statement National Weather Service Topeka KS 1212 PM CDT Sat Jul 11 2020 KSZ009-010-022-023-111745- Pottawatomie-Riley-Washington-Marshall- 1212 PM CDT Sat Jul 11 2020 ...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL RILEY... NORTHWESTERN POTTAWATOMIE...SOUTHEASTERN WASHINGTON AND SOUTHWESTERN MARSHALL COUNTIES UNTIL 1245 PM CDT... At 1212 PM CDT, Doppler radar was tracking a strong thunderstorm near Waterville, moving southeast at 30 mph. Half inch hail and wind gusts up to 50 mph will be possible with this storm. Locations impacted include... Blue Rapids and Waterville. PRECAUTIONARY/PREPAREDNESS ACTIONS... This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && LAT...LON 3957 9651 3938 9667 3961 9693 3976 9679 TIME...MOT...LOC 1712Z 307DEG 26KT 3964 9678 JP
Special Weather Statement
National Weather Service Topeka KS
1219 PM CDT Sat Jul 11 2020
KSZ011-111745-
Nemaha-
1219 PM CDT Sat Jul 11 2020
...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN NEMAHA COUNTY UNTIL
1245 PM CDT...
At 1218 PM CDT, Doppler radar was tracking a strong thunderstorm 7
miles north of Baileyville, moving east at 40 mph.
Half inch hail and wind gusts up to 50 mph will be possible with this
storm.
Locations impacted include...
Sabetha, Seneca, Bern, Goff, Oneida and Woodlawn.
LAT...LON 3994 9579 3987 9579 3965 9594 3990 9624
3998 9624 4000 9623 4000 9600
TIME...MOT...LOC 1718Z 291DEG 34KT 3994 9614
JPThe Topeka radar (KTWX), 47 km away, was scanning. The volume nearest the first event began at 17:59 UTC.
21 hail. Local standard time, as filed.
Reports of several large hailstones falling, including golf ball and baseball sized hail.
Spotter reported hail as large as 3.5 inches in diameter.
Correct previous hail report from 4W Dover. Delayed report of 4.5 inch hail.
Correct previous report from 2 NW Dover. Time estimated by radar.
Per social media post showing 2 inch hailstones.
Per social media post showing 2 inch hailstones.
Report of up to 3.25 inch hail.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Kansas in 2020Every state in 2020This day in weather historyWarnings in Kansas, July 2020
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: 910894, 910895, 910896, 910897, 910898, 910899, 910900, 910901, 910902, 910903, 910904, 910905, 910906, 910907, 910908, 910909, 910910, 910911, 910912, 910913, 910914.