An upper level jet streak remained centered over the Four Corners area. Breaks in cloud cover allowed for deep mixing and breezy conditions at the surface with some gusts meeting high wind criteria in La Plata 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.
An upper level jet streak remained centered over the Four Corners area. Breaks in cloud cover allowed for deep mixing and breezy conditions at the surface with some gusts meeting high wind criteria in La Plata 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 May 10, 1:44 PM MST, 9 minutes earlier.
Area Forecast Discussion National Weather Service Grand Junction CO 244 PM MDT Mon May 10 2021 .SHORT TERM...(Tonight through Tuesday night) Issued at 219 PM MDT Mon May 10 2021 The closed low responsible for our unsettled weather this afternoon remains over central Idaho at this hour. Flow around this low, along with an upper level jet streak, and cooler temperatures aloft have all combined to create a showery, and now stormy afternoon. The HRRR and NAMNest are the big winners this afternoon highlighting where convection has setup and tapped into instability aloft. CAPE values of around 500 J/kg north of I-70 have also aided in said convection. For now, just seeing rainfall amounts of .01 to .03 inches but expect under and near any storm cores that number will be a bit higher. Also wouldn't be surprised if some of the stronger cells don't bring some stronger winds to the surface. Meanwhile down south, plenty of breaks can be seen in the cloud cover which has allowed some deeper mixing to occur. Thanks to the jet streak aloft, a few wind gusts of 50 mph have been noted near Durango and Pagosa Springs this afternoon. Winds have subsided some but expect the breezy conditions to persist through sunset. Overnight, the NAMNEST is hinting at an uptick in precip for the San Juans as do other models, just not as much, so slightly upped pops for the region. Still looking for some light snow overnight in the 1 to 3 inch range for the higher terrain along the Divide and onto the Grand Mesa. Tomorrow, the midlevel circulation will have reached the Co/Wy border and continue moving eastward. Like today, the best instability and strongest CAPE (~300 J/kg) will be north of the I-70 corridor, closest to the disturbance where the best lift will be. Convection doesn't look as widespread and looks to quickly shutdown heading into the evening hours. Down south, another breezy afternoon for the southern valleys. High temps will remain below climatological norms today and again tomorrow but a quick rebound will kick in Wednesday onwards. .LONG TERM...(Tuesday night through Sunday) Issued at 353 AM MDT Mon May 10 2021 A weak ridge begins to build in over the Desert Southwest on Wednesday. Afternoon highs will increase a few degrees each day, and, by the end of the week, are expected to be close to 10 degrees above normal for mid-May. Conditions will remain generally dry through the period. The next Pacific trough moves onshore Friday, and is forecast to deepen along the California coast through the weekend. Ensemble and deterministic models seem to be in pretty good agreement about the general progression of this system, even indicating the formation of a cut off low over northern California Saturday morning. As this trough continues to deepen, the pressure gradient over eastern Utah and western Colorado is expected to tighten up, leading to enhanced afternoon winds for Saturday and Sunday. The winds, combined with warm and dry conditions, may lead to potential critical fire weather conditions for the weekend. The low is currently forecast to move through the Four Corners region Sunday night into Monday, but confidence is low with this occurring at the end of the forecast period. The forecast is likely to change in the coming days as models move into better agreement. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1137 AM MDT Mon May 10 2021 A band of precipitation continues to work its way south, likely bringing some showers and lower CIGS to KMTJ and KGUC within the hour. This band of precipitation has also pushed KASE into IFR conditions, but should return to VFR within an hour as well. Behind this band of showers, convection is beginning to kick off over the higher terrain. Scattered showers and thunderstorms are expected to impact KVEL, KHDN, KEGE, and KASE over the course of the afternoon. These showers with produce gusty and erratic winds, but little in the way of rainfall. VFR conditons are expected, although CIGS may drop below ILS breakpoints with these showers. Shower activity will wind down and become focused along the divide overnight and into tomorrow. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && SHORT TERM...TGR LONG TERM...BGB/MDA AVIATION...TGJT
Hazardous Weather Outlook National Weather Service Grand Junction CO 408 AM MDT Mon May 10 2021 COZ001>014-017>023-UTZ022>025-027>029-111015- 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- 408 AM MDT Mon May 10 2021 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight Scattered showers and isolated thunderstorms possible today, favoring northeast Utah, northwest Colorado and the northern and central higher terrain. Best snow accumulations will remain above 10,000 feet with light rain in the lower elevations. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Mountain snowfall will continue through Tuesday evening as the storm system moves east, favoring the northwest Colorado mountains. Dry and warming trend in store mid week onwards with elevated critical fire weather concerns returning heading into the weekend. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
106 PM MDT MON MAY 10 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1253 PM NON-TSTM WND GST 3 WSW OXFORD 37.15N 107.77W
05/10/2021 M53 MPH LA PLATA CO ASOS
ASOS STATION KDRO DURANGO LA PLATA CNTY
AIRPORT.
&&The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
A peak wind gust of 59 MPH was measured by the automated weather station at the Durango-La Plata County Airport.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2021Every state in 2021This day in weather historyWarnings in Colorado, May 2021
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: 950334.