Thunderstorms initiated along a dry line in central Colorado moving east and forming a cluster of supercells that moved through Dundy, Hitchcock, and Red Willow counties along the Kansas and Nebraska border. The storms produced up to tennis ball sized hail and wind gusts up to 91 mph that blew out windows and garage doors, caused power poles to lean, power outages, and blew down trees along with…
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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 GLD wrote it up.
Thunderstorms initiated along a dry line in central Colorado moving east and forming a cluster of supercells that moved through Dundy, Hitchcock, and Red Willow counties along the Kansas and Nebraska border. The storms produced up to tennis ball sized hail and wind gusts up to 91 mph that blew out windows and garage doors, caused power poles to lean, power outages, and blew down trees along with various sizes of branches.
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 Jul 12, 1:17 PM MST, 2 hours 53 minutes earlier.
Area Forecast Discussion National Weather Service Goodland KS 217 PM MDT Sun Jul 12 2020 .UPDATE... Issued at 217 PM MDT Sun Jul 12 2020 Severe Thunderstorm Watch #363 has been issued for northeast Colorado and adjacent counties in Kansas until 900 pm MDT. Forecast has been updated. Threats are large hail and damaging winds. && .SHORT TERM...(This evening through Monday night) Issued at 143 PM MDT Sun Jul 12 2020 Across the region this afternoon, skies are mainly sunny with some scattered low/high cloud portions of the area. Temperatures are ranging from the mid 80s into the mid 90s, with an area-wide southerly gradient gusting to 30-40 mph at times. For the remainder of the afternoon hrs into tonight, the focus will be just west of the CWA in central Colorado, where convection is expected to initiate along a dryline then shift east with the arrival of a shortwave, then shift SE later tonight as the convection works over the northern periphery of the strong h5 ridge over the southern portion of the country. SPC mesoanalysis has Dcape values 1300-1700 from the Colorado border west, 40-45kts of bulk shear, and decent mid level lapse rates should allow for strong to severe storms to develop. Large hail parameter does indicate large than 1 inch possible. Severe Thunderstorm Watch will probably be issued for portions of the area later this afternoon, with wind and hail highlights. Precipitation that does shift over the CWA will taper by 06z Monday, allowing for dry conditions thru sunrise Monday and a portion of the morning hours. This will lead into Monday/Monday night where a stronger shortwave moves over the region, triggering a potential stronger round of storms. SPC has highlighted most of the CWA in Slight Risk for wind/hail threats, but last outlook update has the enhanced portion sliding further south, which may change later tonight for portions of the CWA. With the potential for more widespread areal coverage of storms, have increased pops slightly, but still in the chance category due to timing into the CWA. For temps, mid to upper 90s for Monday highs, with 60s for lows tonight and Monday night. .LONG TERM...(Monday night through Sunday) Issued at 143 PM MDT Sun Jul 12 2020 This this period of the forecast the long wave trough continues to reside over the central CONUS, flattening the ridge. The resulting zonal flow over the forecast area will allow an upper level short wave trough to move through each afternoon and evening. The GEFS members show a higher high probability of rainfall occurring Tuesday and Wednesday over the Southeast Colorado extending into the southwest part of the forecast area. The dry line will move east of the forecast area Thursday, through the rest of the period. This lowers confidence of storms occurring due to drier air present behind the dry line, despite the aid of the upper level short wave troughs moving through. Am thinking the best chance for any severe thunderstorms will be Tuesday and Wednesday afternoon and evenings before the dry line is pushed east. The cold front still looks to move through Tuesday, lingering into Wednesday. This may also serve as a focus for storm development Tuesday afternoon over the southwestern part of the forecast area. The hot air mass will return Thursday as the cooler air mass is pushed east of the forecast area. Friday and Saturday relative humidity values will fall close to 15% for the northwest part of the forecast area. Winds are forecast to remain below 25 MPH at this time for that part of the forecast area. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) Issued at 1106 AM MDT Sun Jul 12 2020 At this time, VFR conditions are forecast for both terminals. There is the potential for storms to affect KGLD later today, but with timing issues into the area, have left out mention for now. Potential for storms to be in the vicinity of both KGLD/KMCK by the end of the forecast period Monday. Timing issues into the region here as well, so have left out mention of at this time. Winds for KGLD, S around 15-25kts thru 03z Monday, then diminishing to around 10-15kts. Winds for KMCK, S around 15-25kts thru 02z Monday, then SE around 10-15kts. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && UPDATE...JN SHORT TERM...JN LONG TERM...JTL AVIATION...JN
Hazardous Weather Outlook National Weather Service Goodland KS 216 PM MDT Sun Jul 12 2020 COZ090>092-KSZ001>004-013>016-027>029-041-042-NEZ079>081-132015- Yuma County-Kit Carson County-Cheyenne County-Cheyenne-Rawlins- Decatur-Norton-Sherman-Thomas-Sheridan-Graham-Wallace-Logan-Gove- Greeley-Wichita-Dundy-Hitchcock-Red Willow- 216 PM MDT Sun Jul 12 2020 /316 PM CDT Sun Jul 12 2020/ This hazardous weather outlook is for extreme southwest Nebraska... northwest Kansas and east central Colorado. .DAY ONE...THIS AFTERNOON AND TONIGHT... A Severe Thunderstorm Watch is in effect for northeast Colorado and adjacent Kansas counties until 900 PM MDT. Marginal and Slight Risk areas for severe thunderstorms are issued for areas mainly along and west of Highway 25. The main area of focus will be in northeast Colorado and adjacent Kansas counties south of Interstate 70. Threats for severe storms to develop will be around 3-9 pm MDT. Main possible weather threats will be wind gusts to 70 mph and hail up to 1 to 2 inches. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SUNDAY... There is a Slight Risk for severe storms on Monday July 13th. Thunderstorms developing along the Front Range of the Rockies in Colorado and Wyoming may grow upscale and develop into a squall line capable of producing widespread damaging winds late Monday afternoon and evening. .SPOTTER INFORMATION STATEMENT... Spotter activation may be required.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GOODLAND KS
436 PM MDT SUN JUL 12 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0435 PM HAIL 4 NNE VERNON 39.98N 102.24W
07/12/2020 E1.25 INCH YUMA CO TRAINED SPOTTER
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GOODLAND KS
437 PM MDT SUN JUL 12 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0434 PM HAIL 2 ENE VERNON 39.95N 102.25W
07/12/2020 E1.00 INCH YUMA CO CO-OP OBSERVER
.
&&
JRMPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GOODLAND KS
438 PM MDT SUN JUL 12 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0420 PM HAIL 7 E HEARTSTRONG 39.93N 102.45W
07/12/2020 E0.88 INCH YUMA CO PUBLIC
WIND GUSTS OF 30-40 MPH OCCURRED WITH THE
HAIL.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GOODLAND KS
442 PM MDT SUN JUL 12 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0442 PM HAIL 2 SSE WRAY 40.06N 102.21W
07/12/2020 E2.50 INCH YUMA CO PUBLIC
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GOODLAND KS
455 PM MDT SUN JUL 12 2020
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0443 PM HAIL 7 S VERNON 39.84N 102.28W
07/12/2020 E1.00 INCH YUMA CO COCORAHS
&&
JRMSpecial Weather Statement
National Weather Service Goodland KS
506 PM MDT Sun Jul 12 2020
COZ092-122330-
Cheyenne County CO-
506 PM MDT Sun Jul 12 2020
...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN CHEYENNE COUNTY IN
EAST CENTRAL COLORADO UNTIL 530 PM MDT...
At 506 PM MDT, Doppler radar was tracking a strong thunderstorm 11
miles northwest of Cheyenne Wells, moving east at 15 mph.
Penny size hail and winds in excess of 40 mph will be possible with
this storm.
This storm will remain over mainly rural areas of northeastern
Cheyenne County in east central Colorado.
This includes Highway 385 between mile markers 152 and 169.
A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
east central Colorado.
LAT...LON 3903 10257 3904 10242 3904 10240 3905 10239
3905 10225 3882 10227 3885 10259
TIME...MOT...LOC 2306Z 274DEG 14KT 3894 10249
JRMThe Goodland radar (KGLD), 74 km away, was scanning. The volume nearest the first event began at 23:11 UTC.
12 thunderstorm wind, 10 hail. Local standard time, as filed.
Citizen observed an estimated wind gust of 60 mph in the core of a thundestorm.
A CO-OP observer observed an estimated 60 mph wind gust associated with a strong thunderstorm.
Emergency Manager reported a 5 inch diameter tree limb blown down.
Emergency Manager reported at least 2 power poles leaning and 6 inch diameter tree limbs down due to the wind. Half of a locust tree was broken off in town with another uprooted.
A mature pine tree was reported to be blown over.
Citizen reported hail ranging from dime to quarter in size.
Emergency Manager reported power outages in Stratton, Culbertson, Trenton, and Palisade.
Trained spotter observed an estimated 65 mph wind gust.
Quarter sized hail fell for a duration of 5 minutes at the location. The hail and severe wind damaged two windows at the residence.
Citizen reported two double pane windows on the west side of a single family residence were blown out due to strong winds and 1 inch hail.
Hail ranged from dime to penny in size.
Citizen reported quarter sized hail that stripped corn crop of all its leaves.
Citizen reported a two car garage door and window blown out due to strong winds.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Nebraska in 2020Every state in 2020This day in weather historyWarnings in Nebraska, 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: 909675, 909668, 909680, 909659, 909669, 909670, 909671, 909660, 909661, 909676, 909664, 909673, 909677, 909663, 909672, 909665, 909666, 909662, 909674, 909678, 909667, 909679.