The weather pattern of high pressure over the southeast states and an upper trough along the west coast allowed another surge of monsoonal moisture to move into western Colorado. Cooling temperatures aloft allowed large hail to form in some of the stronger storms, while heavy rain and some flash flooding also occurred.
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.
The weather pattern of high pressure over the southeast states and an upper trough along the west coast allowed another surge of monsoonal moisture to move into western Colorado. Cooling temperatures aloft allowed large hail to form in some of the stronger storms, while heavy rain and some flash flooding also occurred.
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 Sep 17, 2:02 PM MST, 3 hours 33 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 302 PM MDT TUE SEP 17 2013 .SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT) ISSUED AT 302 PM MDT TUE SEP 17 2013 SOUTHERLY FLOW IN ADVANCE OF STRONG WEST COAST TROUGH HAS TAPPED INTO LOWER LEVEL MONSOONAL MOISTURE. FIRST LINE OF SHOWERS AND THUNDERSTORMS CURRENTLY MOVING ACROSS NW COLORADO AT 19Z/20Z TIME FRAME. FARTHER UPSTREAM...STORMS THAT HAVE FIRED OVER THE UTAH SPINE HAVE SPREAD INTO THE WRN UINTA BASIN. STORMS ON RADAR LOOKING STRONG WITH SOME ROTATION. WITH SHEAR AXIS AHEAD OF THE WEST COAST TROUGH ENHANCING DEEP LAYERED SHEAR...AGREED WITH THE SEVERE THUNDERSTORM WATCH FOR THE NRN PORTION OF THE FORECAST AREA THROUGH 03Z THIS EVENING. STRONG THUNDERSTORM POSSIBLE SOUTH OF THE WATCH AREA...INCLUDING THE VICINITY OF THE SAN JUAN MOUNTAINS LATER THIS AFTERNOON GIVEN MONSOONAL MOISTURE THAT PERSISTS ACROSS THIS AREA. ENERGY ALOFT DRAGS ACROSS SW COLORADO THIS EVENING...THEREFORE SHOWERS AND STORMS MAY PERSIST BEYOND MIDNIGHT TONIGHT ACROSS THE SAN JUAN MOUNTAINS AND ADJACENT LOWER VALLEYS (DURANGO TO PAGOSA SPRINGS). STRONG TROUGH AXIS MOVING ACROSS THE NRN AND CENTRAL ROCKIES WILL BE LIFTING NORTHEAST. LOWER LEVEL MONSOONAL MOISTURE REMAINS IN PLACE ACROSS THE WESTERN SLOPE FOR AFTERNOON CONVECTION. PWATS WILL BE LOWER FOR LOWER CAPE VALUES...BUT STILL SUFFICIENT MOISTURE FOR ISOLATED STRONG THUNDERSTORMS THAT GENERATE GUSTY WINDS ACROSS SOUTHWEST COLORADO GIVEN GRADIENT FLOW. CONVECTION DIES OUT FAIRLY QUICKLY WEDNESDAY EVENING FOR CLEARING SKIES ACROSS THE ENTIRE REGION. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 302 PM MDT TUE SEP 17 2013 A PROGRESSIVE SERIES OF PACIFIC TROUGHS WILL BRING A ROLLER COASTER RIDE OF SUNNY MILD WEATHER WITH BREEZY SHOWERS MIXED IN OVER THE WEEKEND AND AGAIN NEXT WEDNESDAY. THE DRY AND COOL AIR MASS WILL SETTLE OVER THE FORECAST AREA ON THURSDAY. THE WEST TO EAST COOL FRONT LOOKS TO BE ORIENTED CLOSE TO THE HIGHWAY 50 LINE. THIS WILL BRING 10 DEGREES OF COOLING TO THE NORTH WITH LITTLE CHANGE SOUTH. FLOW ALOFT VEERS TO WNW. THURSDAY NIGHT A RIDGE PROGRESSES INTO UTAH. UNDER CLEAR SKIES AND LIGHT WINDS OVERNIGHT INVERSIONS WILL BECOME STRONG. LOW TEMPERATURES WILL BE WELL BELOW NORMAL WITH NEAR FREEZING TEMPERATURES IN THE CRAIG AREA. FRIDAY THE UPPER RIDGE PASSES...FLOW BACKS TO SW... AND TEMPERATURES RECOVER TO NEAR NORMAL. MOISTURE THAT WAS LURKING JUST BELOW THE FOUR CORNERS BEGINS TO FLOW BACK INTO THE SOUTHERN ZONES FOR A CHANCE OF CONVECTIVE SHOWERS SATURDAY. SW GRADIENT WINDS INCREASE SATURDAY AFTERNOON AND OVERNIGHT. TEMPERATURES CLIMB ABOVE NORMAL. SUNDAY THE NEXT PACIFIC TROUGH PASSES TO THE NORTH. THE LATEST MODEL GUIDANCE PRODUCES MORE SHOWERS AND STORMS THAN IN PREVIOUS MODEL RUNS. THE ASSOCIATED COOL FRONT WITH THIS TROUGH IS CURRENTLY PROGGED TO WEAKEN AND STAY WELL WEST OF THIS FORECAST AREA. ANOTHER PACIFIC TROUGH WILL THREATEN THE AREA NEXT WEDNESDAY. UNTIL THEN SW FLOW ALOFT WILL KEEP BREEZY AND MILD EARLY FALL WEATHER. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 302 PM MDT TUE SEP 17 2013 SCATTERED SHOWERS AND STORMS WILL CONTINUE TO 03Z THIS EVENING. STORM MOTION WILL BE TO THE NORTHEAST AT 20KTS SOUTH...35KTS NORTH. THERE IS A SLIGHT CHANCE OF SEVERE THUNDERSTORMS FROM STRONG WIND GUSTS AND HAIL ACROSS NE UTAH AND FAR NW COLORADO INCLUDING KVEL. SOME BRIEF MVFR VISIBILITIES ARE POSSIBLE DUE TO LOW VIS IN HEAVIER SHOWERS AND STORMS AT ALL AREA AIRPORTS. EXPECT ISOLATED STORMS AND SHOWERS TO CONTINUE BEYOND MIDNIGHT. LOW LEVEL WIND SHEAR IS POSSIBLE THROUGH WEDNESDAY MORNING AS STRONG SW WINDS CONTINUE AT AND ABOVE MOUNTAIN TOP LEVEL. WEDNESDAY SCATTERED CONVECTION WITH LOCAL MVFR CIGS WILL CONTINUE... MAINLY ALONG THE COLORADO SPINE...AHEAD OF THE COOL FRONT. EXPECT MODERATE TURBULENCE IN STRONG SW GRADIENT WINDS WEDNESDAY AFTERNOON. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && SHORT TERM...PF LONG TERM...JOE AVIATION...JOE
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 927 AM MDT TUE SEP 17 2013 COZ001>014-017>023-UTZ022>025-027>029-181300- 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-FLATTOPS- 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- 927 AM MDT TUE SEP 17 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT STRONG THUNDERSTORM WILL BE POSSIBLE THIS AFTERNOON AND EARLY EVENING...ESPECIALLY ACROSS THE NORTHERN AREAS. STRONG GUSTY WINDS TO 50 MPH WILL BE THE MAIN THREAT...BUT ISOLATED STORMS MAY PRODUCE PEA TO MARBLE SIZED HAIL. ISOLATED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE NIGHT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY A DRY COLD FRONT WILL MOVE THROUGH THE AREA WEDNESDAY AFTERNOON AND EVENING BRINGING A SLIGHT CHANCE FOR SOME SHOWERS AND STORMS MAINLY UP NORTH. ONCE IT PASSES...EXPECT CLEAR SKIES AS HIGH PRESSURE BUILDS IN WITH COOL TEMPERATURES EXPECTED THURSDAY BEFORE A WARM UP STARTS FOR THE WEEKEND. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS POSSIBLE TODAY. SPOTTERS ARE ENCOURAGED TO REPORT EXCESSIVE WIND OR HAIL TO THE GRAND JUNCTION FORECAST OFFICE.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GRAND JUNCTION CO 522 PM MDT TUE SEP 17 2013 COZ019-021-UTZ022-028-180000- FOUR CORNERS/UPPER DOLORES RIVER CO-LA SAL AND ABAJO MOUNTAINS UT-SOUTHEAST UTAH UT-SOUTHWEST SAN JUAN MOUNTAINS CO- 522 PM MDT TUE SEP 17 2013 ...SIGNIFICANT WEATHER ADVISORY FOR EASTERN SAN JUAN...NORTHERN MONTEZUMA AND WESTERN DOLORES COUNTIES UNTIL 600 PM MDT... AT 518 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 13 MILES SOUTH OF EASTLAND...OR 22 MILES SOUTHEAST OF MONTICELLO...MOVING EAST AT 30 MPH. HAIL UP TO THE SIZE OF NICKELS AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... DOVE CREEK... CAHONE... 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. HEAVY RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED ROADWAY. LAT...LON 3788 10873 3764 10856 3751 10910 3771 10919 AS
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GRAND JUNCTION CO 550 PM MDT TUE SEP 17 2013 COZ019-021-180045- FOUR CORNERS/UPPER DOLORES RIVER CO-SOUTHWEST SAN JUAN MOUNTAINS CO- 550 PM MDT TUE SEP 17 2013 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN MONTEZUMA AND SOUTHWESTERN DOLORES COUNTIES UNTIL 645 PM MDT... AT 546 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 20 MILES SOUTH OF DOVE CREEK...OR 33 MILES EAST OF BLANDING...MOVING NORTHEAST AT 25 MPH. HAIL UP TO THE SIZE OF NICKELS AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... YELLOW JACKET... LEWIS... 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. HEAVY RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED ROADWAY. LAT...LON 3777 10850 3751 10841 3736 10903 3753 10903 AS
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
602 PM MDT TUE SEP 17 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0450 PM HAIL 7 N VERNAL 40.55N 109.53W
09/17/2013 M1.00 INCH UINTAH UT TRAINED SPOTTER
HAIL ACCUMULATION TWO INCHES DEEP ON HIGHWAY 191. ALSO
MINOR FLOODING OCCURRED ACROSS HIGHWAY 191.
&&
EVENT NUMBER GJT1301526
PRINGLEPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
608 PM MDT TUE SEP 17 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0440 PM HAIL 3 S BLANDING 37.58N 109.48W
09/17/2013 M1.00 INCH SAN JUAN UT PUBLIC
TREES STRIPPED OF LEAVES AND GARDENS FLATTENED DURING
THE SEVEN MINUTE HAIL EVENT. ALSO MINOR FLOODING
OCCURRED.
&&
EVENT NUMBER GJT1301527
PRINGLEPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
626 PM MDT TUE SEP 17 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0445 PM HAIL 5 ESE BLANDING 37.60N 109.40W
09/17/2013 E1.75 INCH SAN JUAN UT AIRPLANE PILOT
&&
EVENT NUMBER GJT1301528
PRINGLEPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
632 PM MDT TUE SEP 17 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0630 PM HAIL 8 NNE FORT DUCHESNE 40.39N 109.80W
09/17/2013 E1.00 INCH UINTAH UT TRAINED SPOTTER
&&
EVENT NUMBER GJT1301529
TBThe Grand Junction radar (KGJX), 175 km away, was scanning. The volume nearest the first event began at 00:33 UTC.
2 hail, 1 flash flood. Local standard time, as filed.
The hail damaged gardens and orchards as it was accompanied by 50 mph winds which snapped off 4 inch diameter tree limbs.
The hail was reported to have damaged cars in the area.
Heavy rainfall on saturated soils led to flash flooding in the Browns Park National Wildlife Refuge, including flood waters that ran into basements of homes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2013Every state in 2013This day in weather historyWarnings in Colorado, September 2013
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: 528992, 528995, 528996.