High-based thunderstorms produced strong outflow winds as the storms collapsed across portions of northwest Colorado.
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The episode as NWS GJT wrote it up.
High-based thunderstorms produced strong outflow winds as the storms collapsed across portions of northwest Colorado.
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 30, 2:14 PM MST, 13 minutes earlier.
Area Forecast Discussion National Weather Service Grand Junction CO 314 PM MDT Fri Aug 30 2019 .SHORT TERM...(Tonight through Saturday night) Issued at 147 PM MDT Fri Aug 30 2019 Scattered thunderstorm activity continues over northwest Colorado and northeast Utah this evening. A very subtle shortwave trough moving through Wyoming is responsible for the slight uptick in organized convective activity this evening. As this system moves east after midnight, any lingering showers will diminish as both moisture, slightly stronger upper level flow, and moisture move east of the Continental Divide. Expect clearing skies with temperatures running near or just slightly above average for lows on Saturday morning. Dry and tranquil weather is expected on Saturday to kick off the Labor Day weekend. The Four Corners high will reestablish itself by afternoon, with dry west to northwest flow in place over eastern Utah and northwest Colorado. Lower PWATs and lack of any forcing will mean little to no shower activity on Saturday, even in the highest terrain of the San Juans. With less cloud cover and drier weather than Friday, Saturday will end up a few degrees warmer. In fact, temperatures on Saturday could end up near record levels (the record in Grand Junction is 98 degrees) with a high high of 98 in the forecast. Expect a dry evening and overnight on Saturday - excellent weather for evening plans on the holiday weekend. .LONG TERM...(Sunday through Friday) Issued at 147 PM MDT Fri Aug 30 2019 High pressure remains firmly entrenched over the Four Corners on Sunday. As a result, another dry day is expected across much of the western slope. The only exception may be in the far southern San Juan Mountains, where a weak push of monsoon moisture may sneak in before sunset, touching off a few showers and storms in the higher terrain near Pagosa Springs. Similar conditions are forecast on Monday - dry and hot except in the south San Juan Mountains. A key message this weekend will center on the potential for fire starts. Given the almost nonexistent monsoon moisture as of late, fine fuels have really dried out across the west slope. While strong winds and lightning are not expected, the Labor Day holiday will bring plenty of recreation to the high country. Fire starts from campfires, parking hot vehicles in grass, dragging chains, etc are all possible. Care should be taken to have a safe holiday weekend, especially when fire is involved. From Tuesday onward, a renewed push of monsoon moisture will surge northward as high pressure slides to the east. An uptick in shower and thunderstorm activity is likely each day through the middle and end of the week. As a result, highs will drop back, possibly within 5 degrees of seasonal averages by the end of the week. Much of western Colorado and eastern Utah is running in a precipitation deficit over the past two months, and it looks like precipitation should run above average from Tuesday through Saturday of next week. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) Issued at 1147 AM MDT Fri Aug 30 2019 A weak disturbance will move east of the Continental Divide early this afternoon, nullifying its impact on TAF sites across eastern Utah and western Colorado. Therefore, the 18Z TAF issuance continued with VFR conditions with all CIGS above ILS breakpoints through the next 24 hours. Thunderstorms over the eastern Uinta mountains and along Colorado's Continental Divide may generate outflows felt at KVEL, KASE, KEGE, KHDN and KGUC during the late afternoon and early this evening. Otherwise, relatively light terrain driven winds will prevail. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && SHORT TERM...MAC LONG TERM...MAC AVIATION...NL
Hazardous Weather Outlook National Weather Service Grand Junction CO 607 AM MDT Fri Aug 30 2019 COZ001>014-017>023-UTZ022>025-027>029-311300- 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- 607 AM MDT Fri Aug 30 2019 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight A few showers and storms are possible over the higher terrain this afternoon but coverage should be marginal. Any convection may bring some gusty outflow winds. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Dry and hot conditions continue with Thursday being the next chance for any significant precipitation. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The Grand Junction radar (KGJX), 170 km away, was scanning. The volume nearest the first event began at 21:26 UTC.
1 thunderstorm wind. Local standard time, as filed.
A trained weather spotter west of Craig measured a peak wind gust of 66 mph from outflow winds associated with a collapsing thunderstorm.
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: 842698.