Lingering subtropical moisture produced some thunderstorms with heavy rainfall.
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 GJT wrote it up.
Lingering subtropical moisture produced some thunderstorms with heavy rainfall.
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 Grand Junction, CO wrote its last area forecast discussion before the first event at Jul 29, 2:45 PM MST, 15 minutes earlier.
Area Forecast Discussion National Weather Service GRAND JUNCTION CO 345 PM MDT Sat Jul 29 2017 .SHORT TERM...(Tonight through Sunday night) Issued at 345 PM MDT Sat Jul 29 2017 Noticeable spin seen on radar this afternoon in southwestern Colorado as a midlevel low pressure system treks across the state. This low, acting in tangent with monsoonal moisture streaming in from down south, has produced another day of scattered showers and thunderstorms. While not as numerous as this time yesterday it'll still be an active evening as storms will be capable of producing heavy rain, gusty outflow winds, and small hail. This morning's upper air sounding had a precipitable water of 1.17 inches so still plenty of available moisture for storms to act on. Drier air has continued to infiltrate northeast Utah and the northwest corner of western Colorado this afternoon under northerly flow aloft as a shortwave trough pushes through the region. Radar has been pretty quiet in this area as a result with webcams showing partly sunny skies. This gradual drying trend will continue overnight as the shortwave moves through so most convection will diminish after midnight, though some isolated showers will linger over the San Juans through morning. Sunday's forecast will be similar to today's with temperatures warming a few degrees and perhaps fewer showers. Precipitable water values are still forecast to exceed an inch further south so showers will favor the central and southern Colorado mountains along the Divide. .LONG TERM...(Monday through Saturday) Issued at 345 PM MDT Sat Jul 29 2017 From Monday onwards, high pressure builds in and is centered over the Great Basin to our west. This will keep the flow generally northerly. However, a few weak disturbances look to drop down from the northwest late Monday and again Thursday which would cause a slight uptick in convection. Some model differences pop up with respect to timing and coverage and also the strength of the disturbances so expect some changes to the forecast over the next few days. Therefore, given model uncertainty, PoPs remain on the conservative side for the extended period. && .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) Issued at 1144 AM MDT Sat Jul 29 2017 Scattered showers and thunderstorms can be expected through 03Z this evening across SE Utah and much of western Colorado, although drier air has infiltrated NW Utah and the NW corner of Colorado where SKC will predominate. Locally heavy rainfall with some storms will produce MVFR ceilings and visibilities. Some storms will also produce small hail and wind gusts to 35 kts. A few lingering showers will likely persist through the night and into Sunday morning east of a KEGE-KCEZ line. Patchy fog in some higher elevation valleys of SW Colorado and near the continental divide of central Colorado 06Z-16Z could locally lower ceilings/visibilities to the IFR category. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && SHORT TERM...MMS LONG TERM...MMS AVIATION...JRP
Hazardous Weather Outlook National Weather Service GRAND JUNCTION CO 449 AM MDT Sat Jul 29 2017 COZ001>014-017>023-UTZ022>025-027>029-301100- Lower Yampa River Basin-Central Yampa River Basin- Roan and Tavaputs Plateaus-Elkhead and Park Mountains- Upper Yampa River Basin-Grand Valley-Debeque to Silt Corridor- Central Colorado River Basin-Grand and Battlement Mesas- Gore and Elk Mountains/Central Mountain Valleys- Central Gunnison and Uncompahgre River Basin- West Elk and Sawatch Mountains-Flat Tops- Upper Gunnison River Valley-Uncompahgre Plateau and Dallas Divide- Northwest San Juan Mountains-Southwest San Juan Mountains- Paradox Valley/Lower Dolores River- Four Corners/Upper Dolores River-Animas River Basin- San Juan River Basin-Southeast Utah-Eastern Uinta Mountains- Eastern Uinta Basin-Tavaputs Plateau-Arches/Grand Flat- La Sal and Abajo Mountains-Canyonlands/Natural Bridges- 449 AM MDT Sat Jul 29 2017 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight Expect scattered thunderstorms this afternoon and evening across the entire area except for some lower elevations in east-central and northeast Utah and northwest Colorado. The southern and central mountains will be favored with some storms moving over adjacent valleys. Locally heavy rain and small hail are possible. .DAYS TWO THROUGH SEVEN...Sunday through Friday Thunderstorms are expected to decrease from Sunday onward as high pressure shifts to the west, cutting off the flow of monsoon moisture. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
1 debris flow, 1 heavy rain. Local standard time, as filed.
Heavy rainfall caused a large amount of mud and rocks to flow across Highway 330 between mile markers 7 and 8.
A total of 1.25 inches of rain was measured within 90 minutes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2017Every state in 2017This day in weather historyWarnings in Colorado, July 2017
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: 715340, 715351.