An abnormal monsoon season brought drier than normal conditions to portions of southeast Utah through the month of August. Low end drought conditions developed by the end of the month.
Every event with a place to put it; 4 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
An abnormal monsoon season brought drier than normal conditions to portions of southeast Utah through the month of August. Low end drought conditions developed by the end of the month.
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 Jul 31, 1:51 PM MST, 10 hours 9 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 251 PM MDT FRI JUL 31 2009 .SHORT TERM...TONIGHT THROUGH SUNDAY... ONE SHORTWAVE TROUGH WILL CONTINUE MOVING EAST THROUGH THE WESTERN CO MTS. SHOWERS AND THUNDERSTORMS ARE ASSOCIATED WELL WITH THE PVA AREA AHEAD OF THE VORT MAX. THESE SHOULD CLEAR THE FORECAST AREA BEFORE SUNSET. A SECOND VORT MAX OVER EASTERN NV APPEARS WILL WEAKEN AND TRAVEL SOUTHWEST OF THE AREA THIS EVENING. A COLD FRONT OVER NORTHERN WY WILL MOVE SOUTH AND EAST THIS EVENING. SHORT-RANGE MODELS SHOW THE WESTERN PORTION OF THE FRONT WEAKENING CONSIDERABLY. BY THE TIME IT REACHES NORTHERN CO AROUND MIDNIGHT TONIGHT IT SHOULD AFFECT ONLY THE NORTHERN MOUNTAINS...WITH LITTLE IF ANY PRECIPITATION WEST OF ABOUT CRAIG. MOST OF ITS ENERGY WILL DROP DOWN THE FRONT RANGE. SIGNIFICANTLY DRIER AIR WILL MOVE INTO THE AREA SATURDAY THROUGH SUNDAY. HIGH PRESSURE OVER THE GREAT BASIN WILL DOMINATE WITH LIGHT NORTHWEST WINDS ALOFT. CLEAR SKIES OVERNIGHT WILL PRODUCE COOL LOW TEMPS...WITH ABUNDANT SUNSHINE ALLOWING MAX TEMPS TO RETURN TO NORMAL AND SLIGHTLY ABOVE NORMAL BY SUNDAY. .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY... MODELS STILL STARTING THE PERIOD IN GOOD AGREEMENT WITH A LOW PRESSURE SYSTEM OFF THE CALIFORNIA COAST...AND A HIGH PRESSURE RIDGE STRETCHED FROM SOUTHERN NM/WESTERN TX ACROSS THE FOUR CORNERS TO THE PACIFIC NORTHWEST. THEN CONSISTENCY BEGINS TO FALTER AS MODELS DECIDE WHAT TO DO WITH THE PACIFIC LOW. THE GFS BRINGS THE LOW INLAND AND OPENS IT UP AS IT TAKES IT ACROSS THE NORTHWEST U.S. THROUGH THE WORK WEEK. THE PREVIOUS RUNS OF THE ECMWF HAD CONSISTENTLY KEPT THE LOW OFF THE COAST...EVEN RETROGRADING IT WITH TIME. BUT THE 12Z EC RUN HAS COME INTO BETTER AGREEMENT WITH THE GFS...AND IS NOW ALSO MOVING THE LOW INTO THE WESTERN PORTION OF THE COUNTRY. CONFIDENCE STILL REMAINS ON THE LOW SIDE WITH THIS FORECAST. IF FUTURE RUNS OF THE EC ARE STILL AS PROGRESSIVE AS THE 12Z RUN...CONFIDENCE WILL INCREASE. A MORE MOIST REGIME IS FAVORED IF THE LOW MOVES OVER THE WEST... SHIFTING THE HIGH EASTWARD...AND RESULTING IN A SOUTHWEST FLOW OVER THE AREA. THE FORECAST ALREADY REFLECTS A LITTLE BETTER MOISTURE BY THE MIDDLE OF NEXT WEEK...WITH THE CHANCE OF DIURNAL SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS EACH DAY. && .AVIATION... SIMILAR CONDITIONS PERSIST WITH CONTINUING VFR CONDITIONS...BUT SCATTERED THUNDERSTORMS THROUGH MID EVENING WILL PRODUCE LOCAL MVFR CONDITIONS...STRONG WIND GUSTS AND SMALL HAIL. STORMS DIMINISH AFTER 03Z...BUT ISOLATED SHOWERS WILL PERSIST BEYOND MIDNIGHT OVER NW COLORADO. && .GJT WATCHES/WARNINGS/ADVISORIES... .CO...NONE. .UT...NONE. SHORT TERM.....CJC LONG TERM......EH AVIATION.......CJC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 600 AM MDT FRI JUL 31 2009 COZ001>014-017>023-UTZ022>025-027>029-011200- ANIMAS RIVER BASIN-ARCHES/GRAND FLAT-CANYONLANDS/NATURAL BRIDGES- CENTRAL COLORADO RIVER BASIN- CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN- CENTRAL YAMPA RIVER BASIN-DEBEQUE TO SILT CORRIDOR- EASTERN UINTA BASIN-EASTERN UINTA MOUNTAINS- ELKHEAD AND PARK MOUNTAINS-FLAT TOPS- FOUR CORNERS/UPPER DOLORES RIVER- GORE AND ELK MOUNTAINS/CENTRAL MOUNTAINS-GRAND AND BATTLEMENT MESAS- GRAND VALLEY-LA SAL AND ABAJO MOUNTAINS-LOWER YAMPA RIVER BASIN- NORTHWEST SAN JUAN MOUNTAINS-PARADOX VALLEY/LOWER DOLORES RIVER- ROAN AND TAVAPUTS PLATEAUS-SAN JUAN RIVER BASIN-SOUTHEAST UTAH- SOUTHWEST SAN JUAN MOUNTAINS-TAVAPUTS PLATEAU- UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE-UPPER GUNNISON RIVER VALLEY- UPPER YAMPA RIVER BASIN-WEST ELK AND SAWATCH MOUNTAINS- 600 AM MDT FRI JUL 31 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT... SCATTERED SHOWERS AND THUNDERSTORMS WILL INCREASE LATE IN THE MORNING AND CONTINUE INTO THE EVENING HOURS. SOME OF THESE THUNDERSTORMS WILL BE STRONG AND GENERATE FREQUENT LIGHTNING... SMALL HAIL AND GUSTY WINDS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY... SATURDAY THROUGH MONDAY...EXPECT DRIER CONDITIONS...BUT ISOLATED AFTERNOON AND EARLY EVENING THUNDERSTORMS WILL FORM OVER THE MOUNTAINS EACH AFTERNOON. TUESDAY THROUGH THURSDAY...THE SUMMER MONSOON SLOWLY RETURNS WITH A CHANCE OF SHOWERS AND THUNDERSTORMS...ESPECIALLY SOUTHWEST COLORADO AND SOUTHEAST UTAH. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT.
The national radar mosaic for the moment the first event began.
4 drought. Local standard time, as filed.
Abnormally dry conditions developed across the area by the end of the month.
Abnormally dry conditions developed across the area by the end of the month.
Abnormally dry conditions developed across the area by the end of the month.
Abnormally dry conditions developed across the area by the end of the month.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Utah in 2009Every state in 2009This day in weather historyWarnings in Utah, August 2009
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: 196502, 196503, 196504, 197367.