During the late afternoon hours of August 7th, a frontal boundary moved across East-Central Colorado allowing for showers and thunderstorms to develop within the region. Some of these thunderstorms became severe and produced large hail up to teacups in size as well as strong wind gusts up to 60 mph.
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 GLD wrote it up.
During the late afternoon hours of August 7th, a frontal boundary moved across East-Central Colorado allowing for showers and thunderstorms to develop within the region. Some of these thunderstorms became severe and produced large hail up to teacups in size as well as strong wind gusts up to 60 mph.
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 Goodland, KS wrote its last area forecast discussion before the first event at Aug 7, 3:18 PM MST, 2 minutes earlier.
Area Forecast Discussion National Weather Service Goodland KS 418 PM MDT Mon Aug 7 2023 .UPDATE... Issued at 413 PM MDT Mon Aug 7 2023 The Severe Thunderstorm Watch has been expanded eastward to include Red Willow, Decatur, and Sheridan counties due to the possibility increasing for severe thunderstorms moving farther eastward than previously anticipated. Billowing clouds are seen on the visible satellite product as well as buoyancy decreasing going eastward. && .SHORT TERM...(This evening through Tuesday Night) Issued at 256 PM MDT Mon Aug 7 2023 At the start of the short term period, the latest upper air RAP analysis shows the CWA with a west-northwesterly flow aloft with a shallow upper air trough out to the east and an upper air low moving just over the coast of WA. Current satellite imagery and surface observations show dry conditions and mostly southerly surface winds with clouds starting to bubble up/develop across a good portion of the CWA particularly in the west. Going forward through the day, models show an upper air shortwave disturbance developing just to the west of the CWA around 21Z that becomes stronger and passes over the CWA at 00Z. This disturbance looks to disappear from influencing the CWA by 06Z while the WA low moves over southern ID overnight. At the surface, the main story looks to be the potential for severe weather expected for this afternoon and evening. When looking at the current RAP analysis, there looks to a good amount of temperature advection at the 850mb level near the CO/KS/NE border area with a good amount of temperature advection across most of the CWA at the 700mb level. Currently, there also looks to be a convergence zone out in the northwestern portion of the CWA that will allow thunderstorms to develop this afternoon and evening. When looking at model convective parameters, MLCAPE values along and west of CO border in the CWA look to be at or above 2 kJ/kg particularly around 21Z-00Z while there looks to be good 0-6km bulk shear across the CWA as well during this time potentially reaching the triple digits in some portions. Also, model forecast 0-3km SRH values around 200 m^2/s^2 are seen within the CWA as well. This lines up pretty well with the SPC marginal to slight risk of severe weather for today. Potential hazards today for storms that become severe look to be large hail up to tennis balls in size, strong wind gusts up to 70 mph, a possible tornado or two (particularly in the northeastern portion of the CWA), and locally heavy rainfall. Isolated supercells look to favor more of the large hail and possible tornado threats, but the strong wind threat will be seen as well if they form a line this evening. The WPC currently has a marginal risk for excessive rainfall for a good portion of the CWA which seems to be well merited with PWAT values over 1 inch to around 1.25 inches seen in the area. There are also some scattered pockets of 1.5 inch PWATs, so heavy rainfall with these thunderstorms is possible and the flood threat will be monitored. Thunderstorms look to develop in the western portions of the CWA around 20Z-21Z and continue eastward across the CO going through 03Z-04Z. This does not look to be a potential tornado outbreak day, but some stronger storms could be possible with a wide variety of hazards so will continue to monitor conditions going forward. A Severe Thunderstorm Watch which includes the potential for tornadoes has also been issued for counties along and west of KS-25 through 03Z. As for tonight after the storms clear the area, lingering precipitation chances are possible for eastern portions of the CWA with overnight lows in the middle 50s to lower 60s. On Tuesday, models show the CWA coming underneath a weak ridge during the day as the northwestern low moves over southern WY by the evening hours. Another shortwave disturbance is seen passing over the CWA during the evening as well. At the surface, models show the possibility for some patchy fog along and north of the KS/NE border during the morning hours. But the main story looks to be the second day of potentially strong to severe thunderstorms seen within the CWA during the late afternoon and evening hours. Currently: the SPC has an enhanced risk for severe weather centered over the northwestern portion of the CWA with most of the remaining parts of the CWA within a slight risk. Again, potential hazards include large hail up to a possible 2 to 3 inches in diameter, strong winds up to 70 mph, locally heavy rainfall leading to potential flash flooding, as well as possible tornado or two. Latest CAM runs show storms developing in eastern CO during 22Z-00Z that will sweep across the northern portions of the CWA going into the night with a possible cold front moving through the region overnight. Looking at convective parameters, model MLCAPE values over 2000 J/kg are seen across the CWA along with 0-6km bulk shear values around 50 kts. As for the potential for heavy rainfall, similar PWAT values of 1-1.25 inches are seen across the CWA though there looks to be a good swath of 1.5 inches along the KS/NE border which supports the WPC excessive rainfall slight risk for a good portion of the CWA. Will continue to watch this storm potential and provide forecast updates as they become available. Daytime highs for Tuesday expect to be in the lower to middle 80s with overnight lows in the lower 50s to lower 60s. .LONG TERM...(Wednesday through Monday) Issued at 357 PM MDT Mon Aug 7 2023 At the start of the long term period, models show a weak upper air trough passing over the CWA on Wednesday morning with the GFS being slightly quicker than the ECMWF in the progression. By Wednesday evening, the front part of a trailing ridge looks to move over the CWA. Going into Thursday, models project the CWA being underneath the ridge through the early afternoon hours before the upper air flow starts to turn more westerly being in the peak of a upper ridge over the south-central CONUS during the evening hours. Models continue to have CWA underneath the peak of the upper air ridge on Friday while showing an upper air low moving off the coast of central CA. An upper air shortwave is seen passing over the CWA during the Friday evening hours as well. Going through the weekend and Monday, long term forecast guidance starts to depart from their solutions a bit though continue to have an upper air high over the TX with the upper air low meandering around the CA coast. The GFS hints at more evening shortwave disturbances passing over the CWA at least during the weekend as well. At the surface, the forecast calls for dry conditions on Wednesday and most of Thursday with slight chances for precipitation seen Thursday night as well as in the latter half of Friday. The best chances for precipitation currently look to be on the weekend and also Monday associated with the potential upper air shortwave disturbances. Will continue to monitor this going forward as details become more clear in future model runs. Temperatures look to cool on Wednesday following a cold front passage before rebounding beginning on Thursday going through the weekend. Daytime highs on Wednesday range between the upper 70s and middle 80s while Thursday through Saturday with highs a few degrees on either side of the 90 degree mark. Sunday's daytime highs are forecasted to be in the middle 80s to lower 90s followed by highs in the middle to upper 80s on Monday. Overnight lows on Wednesday night look to be in the middle 50s to lower 60s while lows in the upper 50s to middle 60s are seen on Thursday through Saturday nights. Sunday and Monday nights have overnight lows ranging between the upper 50s and lower 60s. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1150 AM MDT Mon Aug 7 2023 KGLD...VFR conditions are expected to start the 18Z TAF period with southerly winds at 11G18 kts that become south-southeasterly around 13 kts when chances for thunderstorms begin at 23Z. There is a chance for a severe thunderstorm between 23Z-01Z that may bring some higher to possibly strong winds to KGLD as well. At 02Z, KGLD expects precipitation chances to end with winds becoming east-southeasterly around 9 kts before turning southerly by 05Z. At 14Z, KGLD winds look to increase to around 10G17 kts. KMCK...the 18Z TAF period begins with VFR conditions and south- southeasterly winds around 9 kts. At 23Z, chances for thunderstorms begin with winds turning more southeasterly for KMCK. There is a chance for a severe thunderstorm bringing some possible strong winds to KMCK between 00Z-02Z. By 04Z, thunderstorm chances look to end with winds becoming variable around 6 kts. At 11Z, KMCK sees visibilities dropping to around 3 SM bringing about MVFR conditions before IFR conditions are seen at 12Z when fog possibly lowers visibility to around 1 SM. Visibility looks to improve at 14Z returning KMCK to VFR conditions. With the chances for storms this evening that may become severe, will monitor for better timing and possible impacts in case models show them changing. Medium confidence on fog for KMCK at this time and will re-evaluate this for the 00Z TAF. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && UPDATE...076 SHORT TERM...076 LONG TERM...076 AVIATION...076
Hazardous Weather Outlook National Weather Service Goodland KS 223 PM MDT Mon Aug 7 2023 COZ090>092-KSZ001>004-013>016-027>029-041-042-NEZ079>081-082030- Yuma-Kit Carson-Cheyenne-Rawlins-Decatur-Norton-Sherman-Thomas- Sheridan-Graham-Wallace-Logan-Gove-Greeley-Wichita-Dundy-Hitchcock- Red Willow- 223 PM MDT Mon Aug 7 2023 /323 PM CDT Mon Aug 7 2023/ This hazardous weather outlook is for extreme southwest Nebraska... northwest Kansas and east central Colorado. .DAY ONE...THIS AFTERNOON AND TONIGHT... Severe thunderstorms are expected today across much of the area with destructive hail around the size of a tennis ball, wind gusts to 70 mph and a tornado or two possible. Storms will develop across eastern Colorado around 3 PM MDT (4 PM CDT) and move east through the evening hours. Locally heavy rain is also possible as storms merge into a larger complex tonight. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH MONDAY... For Tuesday, another round of potentially strong to severe storms will impact the area, mainly during the afternoon and evening hours. Hazards include large hail, damaging winds and locally heavy rainfall. There is also a threat for tornadoes along and west of Highway 83, and along and north of Interstate 70. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed beginning around 3 PM MDT (4 PM CDT). Spotters are encouraged to send any storm reports they have from tonight to NWS Goodland.
Preliminary Local Storm Report
National Weather Service Goodland KS
351 PM MDT Mon Aug 7 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0315 PM Hail 6 SE Palisade 40.30N 101.02W
08/07/2023 E2.75 inch Hitchcock NE Public
Delayed report of golf ball to baseball
sized hail a the junction of Highways 6 and
25.
&&
KMKPreliminary Local Storm Report
National Weather Service Goodland KS
353 PM MDT Mon Aug 7 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0340 PM Rain Benkelman 40.05N 101.53W
08/07/2023 M1.50 inch Dundy NE Public
Reported via social media. Rain so far.
&&
KMKSpecial Weather Statement
National Weather Service Goodland KS
356 PM MDT Mon Aug 7 2023
COZ091-072230-
Kit Carson County CO-
356 PM MDT Mon Aug 7 2023
...A strong thunderstorm will impact portions of northeastern Kit
Carson County through 430 PM MDT...
At 356 PM MDT, Doppler radar was tracking a strong thunderstorm 12
miles southwest of Bonny Reservoir, moving east at 35 mph.
HAZARD...Wind gusts up to 50 mph and penny size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
This storm will remain over mainly rural areas of northeastern Kit
Carson County.
This includes the following highways...
Interstate 70 in Colorado between mile markers 449 and 450.
Highway 385 between mile markers 193 and 206, and near mile marker
211.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
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.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Goodland.
A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
east central Colorado.
&&
LAT...LON 3957 10252 3956 10205 3932 10205 3943 10254
TIME...MOT...LOC 2156Z 281DEG 31KT 3951 10237
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH
TriggPreliminary Local Storm Report
National Weather Service Goodland KS
359 PM MDT Mon Aug 7 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0347 PM Hail 5 SE Mcdonald 39.74N 101.30W
08/07/2023 E1.00 inch Rawlins KS Trained Spotter
Spotter reported ongoing dime to quarter
sized hail that has been falling for 10
minutes as of 3:57 PM MT.
&&
KMKSpecial Weather Statement
National Weather Service Goodland KS
410 PM MDT Mon Aug 7 2023
COZ090-NEZ079-072245-
Yuma County CO-Dundy NE-
410 PM MDT Mon Aug 7 2023
...Strong thunderstorms will impact portions of northern Yuma and
northwestern Dundy Counties through 445 PM MDT...
At 410 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 7 miles southwest of Pleasant Valley to 15
miles northwest of Wray to 3 miles north of Eckley. Movement was
southeast at 45 mph.
HAZARD...Wind gusts of 50 to 55 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
These storms will remain over mainly rural areas of northern Yuma and
northwestern Dundy Counties, including the following locations...
Alvin and Wauneta.
This includes Highway 385 between mile markers 251 and 269.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
These storms 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.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Goodland.
A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
northeastern Colorado...and southwestern Nebraska.
&&
LAT...LON 4044 10205 4035 10205 4035 10174 4011 10196
4024 10266 4039 10253 4044 10245
TIME...MOT...LOC 2210Z 324DEG 38KT 4049 10222 4028 10238 4016 10249
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH
TriggPreliminary Local Storm Report
National Weather Service Goodland KS
418 PM MDT Mon Aug 7 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0415 PM Tstm Wnd Gst 10 S Mcdonald 39.65N 101.37W
08/07/2023 M58 MPH Rawlins KS NWS Employee
Off-Duty NWS Employee reported a measured 58
mph with handheld Davis anemometer at 8 ft
high.
&&
KMKThe Goodland radar (KGLD), 115 km away, was scanning. The volume nearest the first event began at 22:22 UTC.
5 hail, 1 thunderstorm wind. Local standard time, as filed.
Report received via social media of half dollar sized hail at location that stripped the corn in a field. Location and time is radar estimated.
Nickel sized hail reported at location.
Spotter reported an estimated 60 mph thunderstorm wind gust at location.
Report received of hail with a measured 1.5 inch diameter at location.
Report received of hail estimated up to teacups in size at location.
Report received via mPing of quarter sized hail at location.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2023Every state in 2023This day in weather historyWarnings in Colorado, August 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: 1130503, 1130504, 1130508, 1130510, 1130511, 1130515.