A very unstable and moist airmass associated with the passage of an upper trough resulted in a severe thunderstorm in Grand County.
Every event with a place to put it. Tap one for its entry below.
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 very unstable and moist airmass associated with the passage of an upper trough resulted in a severe thunderstorm in Grand 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 28, 1:52 PM MST, 38 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 252 PM MDT THU MAY 28 2015 .SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT) ISSUED AT 251 PM MDT THU MAY 28 2015 UPPER LOW SPINNING OVER WESTERN WYOMING IS ADDING STRONG ASCENT OVER OUR WESTERN CWA. THE UPPER JET ROUNDING THE BASE OF THIS LOW IS ACCENTUATING THE LIFT AS THE EXIT REGION NOSES INTO WESTERN COLORADO. STORMS ARE QUITE STRONG IN A SIMILAR REGION AS YESTERDAY AND EXPECT THESE STORMS WILL BE CAPABLE OF STRONG OUTFLOW WINDS AND SOME LARGER HAIL THROUGH THE EARLY EVENING HOURS. AS THE JET CONTINUES TO DIG SOUTHWARD LATE THIS EVENING CONVECTION SHOULD BE ENHANCED TO THE SOUTH WITH ADDED INSTABILITY COMING FROM THE POTENTIAL VORTICITY LOBE ROTATING THROUGH WITH THE JET. THROUGH THE EARLY MORNING HOURS THINGS WILL BE SETTLING DOWN IN THE SOUTH AS THE JET SHIFTS EAST OF THE ROCKIES. UP NORTH COLD ADVECTION AND ENERGY IN THE BACK SIDE OF THE LOW...WHICH IS SETTLING EAST OF THE DIVIDE...SHOULD KEEP SOME ISOLATED SHOWERS GOING OVER THE NORTHERN MOUNTAINS BACK TOWARD THE CRAIG AREA. TEMPERATURES SIMILAR TO YESTERDAY WITH SOME LIGHT SNOW POSSIBLE OVER THE HIGHER PEAKS...PASSES DO NOT APPEAR TO BE IMPACTED AT THIS TIME. FRIDAY...THE TROUGH CONTINUES TO WORK INTO THE CENTRAL PLAINS. SOME WEAK FORCING PERSISTS OVER NW COLORADO WHERE STORMS WILL BE FAVORED. THERE IS ENOUGH RESIDUAL MOISTURE TO FIRE CONVECTIVE STORMS OVER ALL THE NORTHERN AND CENTRAL MOUNTAINS. MORE SUNSHINE OVER THE SOUTH WILL BEGIN THE WARMING TREND THERE. FRIDAY NIGHT...SHOWERS WILL END BEFORE SUNSET. SKIES WILL CLEAR AS A RIDGE AMPLIFIES OVER THE WESTERN GREAT BASIN. TEMPERATURES WILL BE AT OR NEAR NORMAL FOR THE FINAL TIME FOR THE NEXT WEEK AT LEAST. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 251 PM MDT THU MAY 28 2015 A FAST TRANSITION OCCURS THIS WEEKEND FROM STORMY AND COOL TO DRIER AND MUCH WARMER. THE LARGE SCALE PATTERN IS AMPLIFIED AND SLOWLY PROGRESSIVE. A RIDGE DOMINATES THROUGH MONDAY WITH A TROUGH DEVELOPING AFTER TUESDAY. THE RIDGE BUILDS OVER THE REGION BY SUNDAY. SATURDAY WILL BE THE WARMEST DAY OF 2015 SO FAR AND SUNDAY-MONDAY WILL BE ANOTHER 5 DEGREES WARMER. LINGERING MOISTURE AND STRONG AFTERNOON HEATING COULD PRODUCE ISOLATED-SCATTERED STORMS OVER THE MOUNTAINS. THE VALLEYS ARE EXPECTED TO STAY MOSTLY DRY. MONDAY THE RIDGE AXIS IS PUSHED EAST AND FLATTENED AS THE NEXT PACIFIC TROUGH MAKES LANDFALL IN WASHINGTON-OREGON. SW GRADIENT WINDS AND HIGH CLOUDS INCREASE. TEMPERATURES REMAIN SIMILAR TO VERY WARM SUNDAY. TUESDAY THE TROUGH MOVES INTO THE NORTHERN ROCKIES AND DEEPENS INTO THE GREAT BASIN. AN ASSOCIATED WEAK COOL FRONT PASSES TUESDAY NIGHT FOR A SLIGHT COOL DOWN ACROSS THE NORTH. MOISTURE LOOKS VERY LIMITED. WEDNESDAY-THURSDAY THE TROUGH DEEPENS OVER THE INTERMOUNTAIN WEST. SW GRADIENT WINDS CONTINUE BREEZY CONDITIONS. TEMPERATURES REMAIN ABOVE NORMAL. LIMITED MOISTURE MAY PRODUCE SHOWERS AND STORMS MAINLY OVER THE NORTHERN MOUNTAINS. THE FIRST TROPICAL LOW OF THE SEASON THAT HAS BEEN DEVELOPING OFF THE MEXICAN WEST COAST LOOKS TO HEAD WEST AND NOT BE A FACTOR FOR OUR WEATHER NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1036 AM MDT THU MAY 28 2015 INSTABILITY ALONG RIDGE TOPS ALLOWING LATE MORNING CLOUDS TO FORM. THE FOCUS FOR MORE ORGANIZED STORMS WILL BE OVER NORTHERN UTAH AND COLORADO THROUGH THE EVENING. VFR CONDITIONS ARE PREVAILING AT THE FORECAST TERMINALS AND THIS TREND SHOULD REMAIN THROUGH THE NEXT 24 HOURS. KVEL WILL LIKELY BE IMPACTED EARLY IN THE NEW TAF FORECAST WITH PASSING SHOWERS AND THUNDERSTORMS. THE OTHER TERMINAL SITES HAVE LESS CONFIDENCE DUE TO ISOLATED TO SCATTERED NATURE OF THE CONVECTION. THREATS INCLUDE SMALL HAIL AND GUSTY WINDS ALONG WITH TEMPORARY LOWER FLIGHT CONDITIONS DUE TO PASSING MODERATE TO HEAVY RAIN SHOWERS. MOUNTAIN OBSCURATION OVER THE HIGHER PEAKS WILL PERSIST THROUGH SUNSET. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && SHORT TERM...15/JOE LONG TERM...JOE AVIATION...TGJT
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
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1108 AM MDT THU MAY 28 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1106 AM HAIL JARVIE RANCH 40.90N 109.18W
05/28/2015 E0.40 INCH DAGGETT UT CO-OP OBSERVER
WINDS WERE ESTIMATED AROUND 40 MPH.
&&
EVENT NUMBER GJT1500778
15SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1230 PM MDT THU MAY 28 2015
UTZ024-025-281915-
TAVAPUTS PLATEAU UT-EASTERN UINTA BASIN UT-
1230 PM MDT THU MAY 28 2015
...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN UINTAH COUNTY UNTIL 115
PM MDT...
AT 1228 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 29
MILES SOUTH OF MYTON...OR 33 MILES SOUTH OF FORT DUCHESNE...MOVING
EAST AT 30 MPH.
HALF INCH HAIL OR LARGER AND WINDS IN EXCESS OF 40 MPH WILL BE
POSSIBLE WITH THIS STORM.
THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF SOUTHERN UINTAH
COUNTY.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
HEAVY RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD TO
FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS.
THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.
&&
LAT...LON 3972 10996 3972 10995 3973 10995 3977 10992
3979 10993 3980 10992 3979 10992 3979 10988
3980 10989 3981 10989 3981 10994 3990 10992
3981 10925 3955 10934 3965 10998
TIME...MOT...LOC 1828Z 284DEG 28KT 3980 10985
ASSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GRAND JUNCTION CO 1258 PM MDT THU MAY 28 2015 COZ001-003-006-UTZ025-027-281945- ROAN AND TAVAPUTS PLATEAUS CO-LOWER YAMPA RIVER BASIN CO- GRAND VALLEY CO-TAVAPUTS PLATEAU UT-ARCHES/GRAND FLAT UT- 1258 PM MDT THU MAY 28 2015 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN MESA...SOUTHWESTERN GARFIELD...SOUTHEASTERN UINTAH AND NORTHEASTERN GRAND COUNTIES UNTIL 145 PM MDT... AT 1257 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 30 MILES NORTHWEST OF FRUITA...OR 40 MILES NORTHWEST OF GRAND JUNCTION...MOVING EAST AT 15 MPH. UP TO DIME SIZE HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM. THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF NORTHWESTERN MESA...SOUTHWESTERN GARFIELD...SOUTHEASTERN UINTAH AND NORTHEASTERN GRAND COUNTIES. PRECAUTIONARY/PREPAREDNESS ACTIONS... HEAVY RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS. THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE. && LAT...LON 3940 10919 3959 10919 3962 10872 3935 10873 TIME...MOT...LOC 1857Z 271DEG 15KT 3950 10910 AS
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GRAND JUNCTION CO 121 PM MDT THU MAY 28 2015 COZ003-UTZ025-282000- ROAN AND TAVAPUTS PLATEAUS CO-TAVAPUTS PLATEAU UT- 121 PM MDT THU MAY 28 2015 ...SIGNIFICANT WEATHER ADVISORY FOR WESTERN GARFIELD...SOUTHEASTERN UINTAH AND NORTHEASTERN GRAND COUNTIES UNTIL 200 PM MDT... AT 121 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 41 MILES SOUTHWEST OF RANGELY...OR 49 MILES SOUTHEAST OF FORT DUCHESNE...MOVING EAST AT 25 TO 30 MPH. DIME SIZE HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM. THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF WESTERN GARFIELD... SOUTHEASTERN UINTAH AND NORTHEASTERN GRAND COUNTIES. PRECAUTIONARY/PREPAREDNESS ACTIONS... HEAVY RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS. THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE. && LAT...LON 3957 10964 3977 10960 3988 10907 3949 10905 TIME...MOT...LOC 1921Z 271DEG 25KT 3969 10936 AS
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GRAND JUNCTION CO 156 PM MDT THU MAY 28 2015 COZ003-006-UTZ025-027-282045- ROAN AND TAVAPUTS PLATEAUS CO-GRAND VALLEY CO-TAVAPUTS PLATEAU UT- ARCHES/GRAND FLAT UT- 156 PM MDT THU MAY 28 2015 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN MESA...WESTERN GARFIELD...SOUTHEASTERN UINTAH AND NORTHEASTERN GRAND COUNTIES UNTIL 245 PM MDT... AT 155 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 28 MILES NORTHWEST OF FRUITA...OR 38 MILES NORTHWEST OF GRAND JUNCTION...MOVING SOUTHEAST AT 15 TO 20 MPH. DIME SIZE HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM. THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF NORTHWESTERN MESA...WESTERN GARFIELD...SOUTHEASTERN UINTAH AND NORTHEASTERN GRAND COUNTIES. PRECAUTIONARY/PREPAREDNESS ACTIONS... HEAVY RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS. THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE. && LAT...LON 3935 10936 3952 10916 3946 10882 3920 10898 TIME...MOT...LOC 1955Z 301DEG 15KT 3941 10914 AS
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
230 PM MDT THU MAY 28 2015
UTZ025-027-282115-
TAVAPUTS PLATEAU UT-ARCHES/GRAND FLAT UT-
230 PM MDT THU MAY 28 2015
...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN GRAND COUNTY UNTIL
315 PM MDT...
AT 227 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 16
MILES NORTH OF GREEN RIVER...MOVING SOUTHEAST AT 20 TO 25 MPH.
NICKEL SIZE HAIL AND WINDS UP TO 50 MPH WILL BE POSSIBLE WITH THIS
STORM.
THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF NORTHWESTERN GRAND
COUNTY.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
HEAVY RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD TO
FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS.
THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.
&&
LAT...LON 3910 11012 3914 11010 3915 11012 3917 11010
3918 11010 3922 11008 3923 11005 3926 11006
3927 11008 3929 11007 3930 11005 3931 11006
3919 10958 3896 10977 3909 11014
TIME...MOT...LOC 2027Z 293DEG 24KT 3922 11010
ASThe Grand Junction radar (KGJX), 138 km away, was scanning. The volume nearest the first event began at 21:31 UTC.
1 thunderstorm wind. Local standard time, as filed.
A peak gust of 61 mph was measured at the UMTRA tailings disposal site as the result of strong thunderstorm outflow winds. UMTRA workers were sheltered indoors before the strong winds struck the site.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2015Every state in 2015This day in weather historyWarnings in Utah, May 2015
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: 568433.