Subtropical moisture was advected into western Colorado as high pressure remained centered near the Four Corners area. This led to scattered showers and thunderstorms with some storms producing heavy rain and localized debris flows in Pitkin County.
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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 GJT wrote it up.
Subtropical moisture was advected into western Colorado as high pressure remained centered near the Four Corners area. This led to scattered showers and thunderstorms with some storms producing heavy rain and localized debris flows in Pitkin County.
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 Aug 7, 3:44 PM MST, 1 hour 16 minutes earlier.
Area Forecast Discussion National Weather Service Grand Junction CO 444 PM MDT Wed Aug 7 2019 .SHORT TERM...(Tonight through Thursday night) Issued at 257 PM MDT Wed Aug 7 2019 The SubTrop High will be settling over N.Texas while an upstream trough will be invading the NOAM Pacific Coastline. This scenario will create a favorable pattern from the Desert SW to the Central Rockies for a prolonged...uninterrupted tap into the monsoon source region. PWAT have touched an inch along and near the CO/UT border south of the Tavaputs this afternoon. This marker may retreat and surge over our CWA the next few days but for the most part heavy rainfall and associated runoff will remain a threat. This should be favored over steeper terrain and burn scars this afternoon and evening...but as other areas collect heavy rainfall...this threat could spread to lower elevations and Redrock Country tomorrow and in the coming days. This moisture will also be tempering the heat and we will move back to more seasonable afternoon highs. Overnight lows however will likely stay on the mild side with lingering cloud cover through the overnight hours providing a thermal blanket. .LONG TERM...(Friday through Wednesday) Issued at 257 PM MDT Wed Aug 7 2019 Moisture will continue to surge northward around the western periphery of the high pressure stationed over Texas Friday through Sunday. Precipitable water (PW) values will be on the order of 1 to 1.25 inches Friday with around an inch on Saturday. A low pressure system just off the Pacific NW/Northern California coast will be slowly inching closer to the shoreline and making landfall over the Pacific NW by Saturday. This will allow a shortwave to move through the Four Corners region Friday evening into Saturday morning, which may result in an increase in thunderstorm coverage and activity. With all the moisture in place, storms will be capable of producing heavy rain in addition to gusty winds and frequent lightning on Friday and Saturday, favoring the afternoon and evening periods, although some are likely to continue through the overnight Friday night as that shortwave moves through. Storms will be more widespread Friday with activity favoring the western Colorado divide on Saturday afternoon behind the shortwave. Another shortwave moves through on Sunday, with southeast Utah and western Colorado favored for storm activity as drier air slowly works into northeast Utah and northwest Colorado behind this Pacific NW trough. Storms Friday through Sunday though will be capable of heavy rain so flash flooding potential, especially over recent burn scars will need to be watched closely. The Pacific NW trough will allow this moist pattern to break down as the ridge gets flattened and a drier westerly flow takes hold Monday through Wednesday. Still enough moisture will linger for afternoon convection mainly over the western Colorado divide on Monday as PW values will be near 0.75 inches. PW takes a huge drop by Tuesday as most areas will be below 0.5 inches of PW. Mixing will be a bit more enhanced Monday and Tuesday, especially across the north with the upper level jet over the region. Drier air and gusty winds may elevate critical fire weather concerns early next week, so something to keep an eye on. The weekend initially showed this potential, but the latest models are keeping the atmosphere a bit more moist than previously, lessening fire weather concerns. Temperatures through the period will be below normal Friday through Sunday with closer to normal readings next week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 438 PM MDT Wed Aug 7 2019 Showers and thunderstorms coverage will increase this evening then slowly decrease overnight. There is a threat of heavy rainfall with some storms and this could lead to temporary MVFR to IFR conditions until about 03Z. KASE...KTEX and KEGE have the highest probability of these conditions. Expect conditions to improve through the late evening hours though some overnight showers and isolated thunderstorms are likely to persist. Mountains will be obscured at times. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && SHORT TERM...15 LONG TERM...MDA AVIATION...CC
Hazardous Weather Outlook National Weather Service Grand Junction CO 431 AM MDT Wed Aug 7 2019 COZ001>014-017>023-UTZ022>025-027>029-081045- 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- 431 AM MDT Wed Aug 7 2019 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight Monsoonal moisture will increase today contributing to more widespread showers and storms with some potentially lingering through the overnight hours. The biggest concern will be heavy rain under the strongest, slow-moving storms. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Expect additional storm development Thursday with coverage on Friday likely limited to eastern portions of the forecast area. Precipitation chances (limited to the higher terrain) lessen each day through the weekend. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected today or tonight, however spotters are encouraged to relay rainfall amounts or any observed flooding to the National Weather Service in Grand Junction.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
323 PM MDT WED AUG 7 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0322 PM HEAVY RAIN MONTROSE 15W 38.46N 108.16W
08/07/2019 E0.30 INCH MONTROSE CO TRAINED SPOTTER
RAIN FELL IN 20 MINUTES.
&&
MDAThe national radar mosaic for the moment the first event began.
1 debris flow. Local standard time, as filed.
Showers and thunderstorms produced heavy rain which led to a mudslide along County Road 3 near Marble. The road was closed in both directions as a result.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2019Every state in 2019This day in weather historyWarnings in Colorado, August 2019
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: 836263.