Monsoonal moisture advected into the region and produced showers and thunderstorms, favoring west-central and southwest Colorado. Gusty and erratic winds were the primary threat with storms with some stronger cells producing severe gusts.
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The episode as NWS GJT wrote it up.
Monsoonal moisture advected into the region and produced showers and thunderstorms, favoring west-central and southwest Colorado. Gusty and erratic winds were the primary threat with storms with some stronger cells producing severe gusts.
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 16, 2:00 PM MST, 37 minutes earlier.
Area Forecast Discussion National Weather Service Grand Junction CO 300 PM MDT Thu Jul 16 2020 .SHORT TERM...(Tonight through Friday night) Issued at 300 PM MDT Thu Jul 16 2020 Scattered to numerous showers and thunderstorms have developed south of I-70 as expected today with isolated coverage across the north. Gusty outflow winds to 40 MPH, lightning and brief moderate rain has been reported with the stronger storms. In fact, the Aspen-Pitkin County Airport picked up a tenth of an inch of rain in the last hour with higher amounts estimated by radar across portions of the Uncompahgre River Basin. CAM guidance shows this shower and storm activity persisting through the evening before beginning to diminish around sunset. However, as has been the case the last several nights, some showers will linger overnight, favoring the Four Corners region. Temperatures are running 3 to 6 degrees cooler this afternoon in response to increased clouds and showers with as much as a ten degree difference near Monticello. The area of high pressure centered over the Southern Plains will begin to slowly drift westward beginning tonight and continuing on Friday. This will allow westerly flow aloft to become more pronounced over the northwest and west-central portions of the forecast area, resulting in drier conditions. Moisture riding the backside of the ridge will continue to stream into the eastern and southern zones, resulting in another round of showers and thunderstorms Friday afternoon. Gusty outflow winds and lightning will remain valid threats and, with PWATs of 0.70 to 0.90 inches along the Divide, brief downpours will again be possible. Friday night looks to be fairly dry as the high continues to drift to the west, shutting off that tap of subtropical moisture to our region. .LONG TERM...(Saturday through Thursday) Issued at 300 PM MDT Thu Jul 16 2020 Saturday and Sunday will see high pressure remain over eastern Utah and western Colorado. Residual moisture will keep the threat for showers and thunderstorms in the forecast along the Divide each day, though PWATs will be on a downward trend which will minimize the potential for heavier rainfall. The valleys on the other hand will remain dry with temperatures running several degrees above normal. This trend will continue into the new work week before the synoptic pattern begins to shift around midweek. A trough of low pressure will elongate off the west coast late Wednesday before progressing inland on Thursday. This will shift the subtropical high back towards the Southern Plains which would allow for southerly flow to advect subtropical moisture into the forecast area. If this forecast remains on track, we can expect a cooler and wetter end to the long term period. However, even now discrepancies exist in how broad the approaching trough will be. If the trough weakens or stalls this would impact the high's progression eastward. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 1138 AM MDT Thu Jul 16 2020 Scattered showers and thunderstorms will continue to develop over higher terrain this afternoon, drifting to the east-northeast. Storms will favor TAF sites across southwest and west-central Colorado with the main threat of gusty outflow winds, though brief periods of heavy rainfall are possible with stronger storms. Coverage will decrease after sunset, however, lingering showers are possible across higher terrain. Similar pattern is expected tomorrow with convection redeveloping across higher terrain early Friday afternoon. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && SHORT TERM...MMS LONG TERM...MMS AVIATION...ERW
Hazardous Weather Outlook National Weather Service Grand Junction CO 450 AM MDT Thu Jul 16 2020 COZ001>014-017>023-UTZ022>025-027>029-171100- 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- 450 AM MDT Thu Jul 16 2020 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight Thunderstorm development will again occur with the heating of the day and a better push of moisture will allow for an uptick in coverage. Gusty outflow winds will remain the main threat from storms. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Thunderstorm development can be expected each day through Wednesday with the best coverage remaining over the Colorado mountains. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The Grand Junction radar (KGJX), 67 km away, was scanning. The volume nearest the first event began at 21:37 UTC.
1 thunderstorm wind. Local standard time, as filed.
A peak wind gust of 59 mph was measured by the automated weather station at the Rifle Garfield County Airport.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2020Every state in 2020This day in weather historyWarnings in Colorado, 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: 894272.