A ridge of high pressure shifted to the east allowing deep monsoonal moisture to continue streaming into the area, which produced thunderstorms with heavy rainfall. An area in San Miguel County received heavy rainfall which caused a mudslide.
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 ridge of high pressure shifted to the east allowing deep monsoonal moisture to continue streaming into the area, which produced thunderstorms with heavy rainfall. An area in San Miguel County received heavy rainfall which caused a mudslide.
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 1, 2:05 PM MST, 2 hours 42 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 305 PM MDT SUN SEP 1 2013 .SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT) ISSUED AT 304 PM MDT SUN SEP 1 2013 SUBTLE SHIFT OF THE UPPER LEVEL RIDGE AS ALLOWED DRIER AIR TO SNEAK INTO THE FORECAST AREA OVER THE PAST 24 HOURS. THIS HAS RESULTED IN LESS CONVECTIVE ACTIVITY THIS AFTERNOON WITH STORMS HAVING TO OVERCOME WEAK SUBSIDENCE. STORM MOTION HAS BEEN ALL OVER THE DIAL WITH LIGHT WINDS ALOFT UNDER THE CENTER OF THE RIDGE. WATER VAPOR SHOWING DRIER AIR FROM TEXAS SLICING ACROSS NEW MEXICO AND ARIZONA...SHUNTING THE DEEP MONSOONAL PUSH TO THE WEST INTO THE BAJA REGION...WITH UPPER JET FLOW FLATTENING AS WELL...WHICH IS SQUEEZING DRIER NORTHERN AIR INTO OUR NORTHEAST ZONES. SO SQUEEZE PLAY IS BASICALLY ON THIS AFTERNOON WITH DRYING TO THE NORTH AND SOUTH AND LINGERING MOISTURE UNDER THE RIDGE GETTING PLAYED OUT NEAR THE HIGH PEAKS. ACTIVITY IS BECOMING MORE DIURNAL...WITH CONVECTION DIMINISH AFTER 9 PM WITH ONLY ISOLATED SHOWERS LINGERING INTO THE EARLY MORNING HOURS. VERY SIMILAR DAY IN STORE TOMORROW WITH SCATTERED MOUNTAIN CONVECTION AND ISOLATED VALLEY ACTIVITY. PATTERN ALMOST LOOKS MORE LIKE EARLY JUNE VERSUS EARLY SEPTEMBER. NO MAJOR SWINGS IN TEMPS WITH PERSISTENCE A GOOD START. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 304 PM MDT SUN SEP 1 2013 AN UNSEASONABLY STRONG HIGH PRESSURE SYSTEM...AT 5960 METERS... WILL REMAIN CENTERED OVER CENTRAL COLORADO THROUGH SATURDAY. THIS WILL PRODUCE LIGHT WINDS ALOFT...ABOVE NORMAL AFTERNOON TEMPERATURES...AND ONLY A LOW GRADE MONSOONAL DIURNAL STORM PATTERN. PRECIPITABLE WATER VALUES WILL BE LOWER THAN THE LAST FEW WEEKS IN THE 0.9 TO 0.7 INCH RANGE. STILL WITH SLOW STORM MOTION...LOCALLY HEAVY SHOWERS ARE A POSSIBILITY FAVORING THE SOUTH. MODELS ARE IN GOOD AGREEMENT FOR A PATTERN CHANGE STARTING NEXT WEEKEND. THE EASTERN PACIFIC LOW THAT HAS BEEN MORE OR LESS STATIONARY ALONG THE WEST COAST FOR THE LAST MONTH...KICKS INLAND NEXT SATURDAY AND THROUGH THE NORTHERN ROCKIES ON SUNDAY. THIS WILL FLATTEN THE RIDGE WELL TO OUR SOUTH AND ADVECT MUCH DRIER AIR IN FROM THE WEST TO NORTHWEST. THE TRANSITION TO THIS DRIER AIR MASS MAY BE A PERIOD OF ENHANCED OR STRONGER THUNDERSTORMS. WITH STORM MOTION AND SHEAR INCREASING THE MAIN THREAT FROM THESE STORMS WILL BE STRONG GUSTY OUTFLOW WINDS FAVORING THE NORTH. THE NEW AIR MASS DOES NOT LOOK SIGNIFICANTLY COOLER...SO HAIL IS LESS OF A THREAT. THIS PERIOD IS CURRENTLY TIMED FOR LATE SATURDAY OR SUNDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 304 PM MDT SUN SEP 1 2013 SCATTERED SHOWERS AND THUNDERSTORMS...SOME OBSCURING MOUNTAIN PEAKS...WILL DIMINISH BY 03Z THIS EVENING...WITH ONLY ISOLATED SHOWERS LINGERING OVERNIGHT. EXPECT ANOTHER ROUND OF MOUNTAIN STORMS AFTER 18Z MONDAY. VFR CONDITIONS WILL PERSIST AT VALLEY SITES THROUGH THE PERIOD...ALTHOUGH A BRIEF LOWERING OF CIGS CAN BE EXPECTED NEAR SHOWERS AND THUNDERSTORMS. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && SHORT TERM...JDC LONG TERM...JOE AVIATION...JDC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 606 AM MDT SUN SEP 1 2013 COZ001>014-017>023-UTZ022>025-027>029-021300- 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- 606 AM MDT SUN SEP 1 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ONCE AGAIN THIS AFTERNOON AND EVENING...PRIMARILY OVER THE HIGHER TERRAIN. BRIEF HEAVY RAIN WILL BE POSSIBLE THAT MAY CAUSE A RISE IN MOUNTAIN STREAMS AND POSSIBLE MUD DEBRIS FLOWS. SHOWERS AND THUNDERSTORMS WILL BE LESS NUMEROUS OVER THE DESERT VALLEYS. .DAYS TWO THROUGH SEVEN...LABOR DAY THROUGH SATURDAY SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM OVER THE MOUNTAINS BY EARLY AFTERNOON. SHOWERS AND THUNDERSTORMS WILL BE MORE ISOLATED IN DESERT VALLEYS. BRIEF HEAVY SHOWERS WILL BE POSSIBLE WITH THUNDERSTORMS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED TODAY OR TONIGHT...HOWEVER SPOTTERS ARE ENCOURAGED TO RELAY RAINFALL AMOUNTS OR ANY OBSERVED FLOODING TO THE GRAND JUNCTION FORECAST OFFICE.
The national radar mosaic for the moment the first event began.
1 debris flow. Local standard time, as filed.
Local law enforcement reported a mudslide in Sawpit. The KGJX radar estimated between 1.00 and 1.50 inches of rain in this area which is known for mudslides when heavy rain occurs.
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: 517437.