A distinct moisture gradient existed ahead of and behind a cold front situated across northeast Utah and northwest Colorado. Scattered showers and storms developed ahead of this boundary and given dry air at low levels, storms were high based producing virga and strong outflow winds.
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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.
A distinct moisture gradient existed ahead of and behind a cold front situated across northeast Utah and northwest Colorado. Scattered showers and storms developed ahead of this boundary and given dry air at low levels, storms were high based producing virga and strong outflow winds. Wind gusts exceeded 58 mph in La Plata county due to virga.
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 20, 4:41 PM MST, 12 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Grand Junction CO 541 PM MDT Mon May 20 2024 .KEY MESSAGES... - Showers and thunderstorms will spread south and eastward tonight as the cold front associated with a late season spring storm moves through the area tonight. - Colder air will cause snow to develop in the mountains with accumulation's above 9,000 feet expected to range from 2 to 5 inches with locally higher amounts. - Cooler temperatures behind the front on Tuesday will bring markedly cooler temperatures with highs dipping by close to 15 degrees relative to today's highs. && .SHORT TERM /THROUGH TUESDAY NIGHT/... Issued at 247 PM MDT Mon May 20 2024 Showers and isolated thunderstorms continued to fire along and northwest of the cold front associated with the late spring storm over the Great Basin. This activity has remained northwest of a line from KDWX to 30S KPUC and isn't likely to shift much over the next few hours. Meanwhile, there is a marginal threat of severe wind gusts from stronger cells over the northwest through early evening. South and east of the line, strong gusty south to southwest winds were the rule, and while clouds have increased, no showers were apparent. The trough axis shifts eastward tonight while a vort lobe rotating through the base of the trough drives the cold front across the forecast area. Dynamic forcing along with convergence along the boundary will cause showers to move to the east and expand southward with showers becoming more likely as the night progresses. Infiltration of colder air will bring snow levels down to near 7000 feet over northeast Utah and northwest Colorado while hovering from 8500 to 9000 feet elsewhere. Mountain snow will largely be confined to areas above 8500 feet in the north and 9000 feet in the south with accumulations more notable above 9000 and 10000 feet, respectively. Not enough snow indicated to issue Winter Weather Advisories, but mountain passes are likely to see impacts, especially at Rabbit Ears and Vail Passes. Some of the trough's energy shifts to the northern Plains on Tuesday, but the main trough is expected to pass over the area during the day. As a result, showers and thunderstorms remain likely over the mountains with the northern and central ranges favored and lesser chances over the lower elevations of eastern Utah and southwest Colorado. Total mountain snowfall from this event is expected to be around 3 to 6 inches in the higher elevations and locally up to 10 inches on favored peaks and ridges. Temperatures will be markedly cooler behind the front with highs running close to 10 degrees below seasonal norms. Drying and clearing is expected in the subsident region in the wake of the trough Tuesday night. As a result, we'll see an end to shower activity while clearing and colder air brings unusually cool overnight lows with temperatures also dipping to near 10 degrees below normal, though it doesn't appear a damaging freeze will occur in areas with sensitive vegetation. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 247 PM MDT Mon May 20 2024 Much drier weather is in store on Wednesday in the wake of our departing trough, but a few returning spotty showers can't be ruled out across the Continental Divide mountains given lingering residual moisture and daytime heating. High temperatures will be roughly 4 to 8 degrees below normal for this time of year. By Thursday, mid-level flow becomes southwesterly again out ahead of another deep trough and cold front digging across the Intermountain West. In response, developing warm advection within the southwest flow ahead of the front will boost high temperatures by about 5 degrees compared to Wednesday... and more in line with seasonal norms. The cold front is progged to move across eastern Utah and western Colorado Thursday afternoon and evening, bringing another shot of cooler air in its wake. As for precipitation chances, moisture along and ahead of the front is modest at best, so despite decent forcing, slight chance to chance PoPs are mainly confined to the high terrain well to the north of the I-70 corridor, and QPF is mostly under a tenth of an inch. Behind the front, a cooler day is expected to round out the work week on Friday with highs once again several degrees below normal. A couple trailing waves have the potential to bring a few more rounds of unsettled weather Friday into the weekend, though significant differences still exist amongst the latest models. For now, will continue to lean on the blended solution, which favors northeast Utah, northwest Colorado, and the higher elevations along and north of I-70 for any additional precipitation. Given the potential for more clouds and precip, temperatures will continue to run a few to several degrees below normal. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 535 PM MDT Mon May 20 2024 Strong southerly to southwesterly winds will continue to impact terminals along and south of the I-70 corridor between now and 06z. These winds will turn northwesterly and weaken in the wake of a cold front currently moving through eastern Utah. Showers along and ahead of this front, as well as showers produced by daytime heating along terrain features, will be capable of producing erratic winds with gusts in excess of 40 knots. Brief heavy rain, small hail, and lightning will also be threats with more organized showers and storms. Lighter, more stratiform showers will linger behind the front through 12z or so tomorrow morning, holding on longest over the higher terrain. Only the very highest elevations can expect snow. KASE, KEGE, and KRIL can expect to remain below ILS Breakpoints between 06z and 12z, and all terminals can expect periods of MVFR/IFR conditions with passing showers and with the cold front. Otherwise, VFR conditions will prevail. Gusty winds will return for tomorrow afternoon. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && SHORT TERM...NL LONG TERM...MDM AVIATION...TGJT
Hazardous Weather Outlook National Weather Service Grand Junction CO 1243 PM MDT Mon May 20 2024 COZ003-006>014-017>023-UTZ022-025-027>029-211845- Roan and Tavaputs Plateaus-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-Tavaputs Plateau- Arches/Grand Flat-La Sal and Abajo Mountains- Canyonlands/Natural Bridges- 1243 PM MDT Mon May 20 2024 This Hazardous Weather Outlook is for northwest Colorado, southwest Colorado, west central Colorado, east central Utah and southeast Utah. .DAY ONE...This afternoon and tonight. Warm and windy conditions today ahead of a cold front will bring wind gusts 30 to 40 mph across the region. Near critical fire weather conditions this afternoon are expected around the Four Corners, where fuels remain sub-critical. Showers and thunderstorms along the front will work through the region this afternoon and into the overnight hours. Gusty outflows and small hail are expected in storms today. Accumulating mountain snows expected above 10000 feet tonight, as cold air behind the front lowers freezing levels. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Scattered showers and thunderstorms will continue on Tuesday behind the front. Gusty outflow winds and small hail will remain a threat in thunderstorms on Tuesday. Quieter conditions return Wednesday into late week, when unsettled weather returns to the region. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected today or tonight, however spotters are encouraged to report excessive wind or any observed wind related damage to the National Weather Service in Grand Junction. COZ001-002-004-005-UTZ023-024-211845- Lower Yampa River Basin-Central Yampa River Basin- Elkhead and Park Mountains-Upper Yampa River Basin- Eastern Uinta Mountains-Eastern Uinta Basin- 1243 PM MDT Mon May 20 2024 This Hazardous Weather Outlook is for northwest Colorado and northeast Utah. .DAY ONE...This afternoon and tonight. Slightly cooler and windy conditions today ahead of a cold front will bring wind gusts 30 to 40 mph across the region. Showers and thunderstorms along the front will work through the region this afternoon and into the overnight hours. Gusty outflows with the potential to produce gusts in excess of 60 mph and small hail are expected with some storms today. Accumulating mountain snows expected above 10000 feet tonight, as cold air behind the front lowers freezing levels. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Scattered showers and thunderstorms will continue on Tuesday behind the front. Gusty outflow winds and small hail will remain a threat in thunderstorms on Tuesday. Quieter conditions return Wednesday into late week, when unsettled weather returns to the region. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected today or tonight, however spotters are encouraged to report excessive wind or any observed wind related damage to the National Weather Service in Grand Junction.
Special Weather Statement
National Weather Service Grand Junction CO
231 PM MDT Mon May 20 2024
COZ001-UTZ024-202100-
Lower Yampa River Basin CO-Eastern Uinta Basin UT-
231 PM MDT Mon May 20 2024
...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN RIO BLANCO COUNTY
THROUGH 300 PM MDT...
At 231 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles south of Dinosaur, or 37 miles southeast of Vernal, moving
northeast at 35 mph.
HAZARD...Wind gusts up to 50 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Rangely and Blue Mountain.
This includes the following highways...
U.S. Highway 40 in Colorado between mile markers 5 and 19.
Colorado 64 between mile markers 2 and 20, and between mile markers
24 and 32.
Colorado 139 near mile marker 72.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 4002 10905 4012 10914 4036 10883 4014 10856
TIME...MOT...LOC 2031Z 234DEG 33KT 4011 10899
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH
MillerSpecial Weather Statement
National Weather Service Grand Junction CO
255 PM MDT Mon May 20 2024
COZ001-002-202130-
Lower Yampa River Basin CO-Central Yampa River Basin CO-
255 PM MDT Mon May 20 2024
...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN MOFFAT COUNTY
THROUGH 330 PM MDT...
At 255 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles north of Rangely, or 43 miles east of Vernal, moving northeast
at 35 mph.
HAZARD...Wind gusts up to 50 mph and half inch hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Massadona.
This includes U.S. Highway 40 in Colorado between mile markers 13 and
35.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4015 10882 4021 10888 4046 10860 4026 10839
TIME...MOT...LOC 2055Z 232DEG 31KT 4022 10877
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH
MillerPreliminary Local Storm Report
National Weather Service Grand Junction CO
500 PM MDT Mon May 20 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0453 PM Non-Tstm Wnd Gst 2 E Rifle 39.53N 107.73W
05/20/2024 M47 MPH Garfield CO ASOS
ASOS station KRIL Garfield County Rgnl AP.
&&Preliminary Local Storm Report
National Weather Service Grand Junction CO
540 PM MDT Mon May 20 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0541 PM Dust Storm 1 E Elgin 38.97N 110.14W
05/19/2024 Grand UT Public
Near zero visibility along I-70 near Green
River due to blowing dust from thunderstorm
outflow winds. Report from May 19 at 5:41 pm
MDT.
&&
MDAPreliminary Local Storm Report
National Weather Service Grand Junction CO
541 PM MDT Mon May 20 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0307 PM Non-Tstm Wnd Gst 1 W Douglas Pass 39.60N 108.82W
05/20/2024 M62 MPH Garfield CO Mesonet
Mesonet station CO098 139s034 Douglas Pass.
0516 PM Non-Tstm Wnd Gst 3 NW Fruitvale 39.12N 108.52W
05/20/2024 M46 MPH Mesa CO ASOS
ASOS station KGJT Grand Junction Rgnl AP.
0142 PM Non-Tstm Wnd Gst 16 NW Moab 38.75N 109.75W
05/20/2024 M45 MPH Grand UT ASOS
ASOS station KCNY 16 NW Moab.
0444 PM Non-Tstm Wnd Gst 3 WSW Oxford 37.15N 107.77W
05/20/2024 M44 MPH La Plata CO ASOS
ASOS station KDRO Durango La Plata Cnty
Airport.
0426 PM Non-Tstm Wnd Gst 2 ESE Gypsum 39.63N 106.92W
05/20/2024 M43 MPH Eagle CO AWOS
AWOS station KEGE Eagle County Rgnl Airport.
0209 PM Non-Tstm Wnd Gst 2 NW Montrose 38.50N 107.90W
05/20/2024 M41 MPH Montrose CO ASOS
ASOS station KMTJ Montrose Rgnl Airport.
0401 PM Non-Tstm Wnd Gst 2 ESE Craig 40.50N 107.52W
05/20/2024 M40 MPH Moffat CO ASOS
ASOS station KCAG Craig-Moffat County
Airport.
&&Preliminary Local Storm Report
National Weather Service Grand Junction CO
542 PM MDT Mon May 20 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0529 PM Tstm Wnd Gst 3 NW Fruitvale 39.12N 108.52W
05/20/2024 M46 MPH Mesa CO ASOS
ASOS station KGJT Grand Junction Rgnl AP.
Associated with passing virga showers.
&&The Grand Junction radar (KGJX), 216 km away, was scanning. The volume nearest the first event began at 23:52 UTC.
1 thunderstorm wind. Local standard time, as filed.
A peak wind gust of 66 MPH was measured by the automated weather station at the Durango-La Plata County Regional Airport due to virga showers.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2024Every state in 2024This day in weather historyWarnings in Colorado, May 2024
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: 1180593.