The abnormally dry monsoon season allowed drought conditions to persist throughout the month across southwest portions of Colorado, spreading further into portions of west central Colorado. Conditions across extreme southwest Colorado escalated into the moderate drought category.
Every event with a place to put it; 15 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.
The abnormally dry monsoon season allowed drought conditions to persist throughout the month across southwest portions of Colorado, spreading further into portions of west central Colorado. Conditions across extreme southwest Colorado escalated into the moderate drought category.
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 Aug 31, 7:00 PM MST, 5 hours earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 800 PM MDT MON AUG 31 2009 .UPDATE... SEE FIRE WEATHER DISCUSSION BELOW. && .SHORT TERM...TONIGHT THROUGH WEDNESDAY... FLOW AROUND HIGH PRESSURE CENTERED OVER THE NM/AZ BORDER CARRIED SMOKE FROM FIRES IN THE LOS ANGELES AREA OVER THE NORTHERN TWO THIRDS OF THE STATE THIS AFTERNOON RESULTING IN WIDESPREAD HAZE. MEANWHILE ...LOW PRESSURE MOVING THROUGH THE NORTHERN ROCKIES RESULTED IN AN INCREASED PRESSURE GRADIENT OVER THE AREA DRIVING BREEZY WEST TO SOUTHWEST WINDS THIS AFTERNOON. FINALLY...MID-LEVEL MOISTURE OVER THE SOUTHERN MOUNTAINS FUELED A FEW HIGH BASED THUNDERSTORMS OVER THE EASTERN SAN JUAN MOUNTAINS EARLY THIS AFTERNOON. EXTRAPOLATED VISIBLE SATELLITE IMAGERY INDICATED THE SMOKE WILL LINGER OVER THE NORTHERN HALF OF THE CWFA THIS EVENING BEFORE PUSHING NORTHEAST OF THE AREA LATE TONIGHT. WINDS WILL DIMINISH AS DEEP MIXING BREAKS DOWN AFTER SUNSET AND NORMAL DRAINAGE FLOWS WILL BECOME ESTABLISHED OVERNIGHT. ISOLATED STORMS WILL PERSIST INTO THE EARLY EVENING...THOUGH MODELS NOW SUGGEST ONLY THE SOUTH LIKELY TO BE IMPACTED AS DRIER AIR MOVES OVER THE NORTHERN ZONES. SIMILAR CONDITIONS EXPECTED TOMORROW...THOUGH GRADIENT WEAKENS AS THE NORTHERN LOW FILLS AND SLIDES EASTWARD...THEREFORE LESS WIND ANTICIPATED. HOWEVER...CIRCULATION AROUND THE HIGH COULD BRING MORE SMOKE FROM SOUTHERN CA DEPENDING UPON THE INTENSITY OF THOSE FIRES LATE TODAY AND TONIGHT. RIDGE REBUILDS OVER THE AREA WEDNESDAY AND THE AIRMASS WILL REMAIN RELATIVELY DRY. MODELS HINT AT A FEW STORMS ALONG THE CONTINENTAL DIVIDE DURING THE AFTERNOON AND EVENING. TEMPERATURES WILL REMAIN ABOVE NORMAL DURING THE PERIOD AND GENERALLY FOLLOWED THE WARMER MET GUIDANCE. && .LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY... GOOD MODEL CONSISTENCY IS ADDING CONFIDENCE TO FORECAST DETAILS. THERE IS THE POTENTIAL FOR A SIGNIFICANT MONSOONAL SURGE THIS WEEKEND. WEDNESDAY NIGHT-FRIDAY: THE UPPER RIDGE AXIS REMAINS ANCHORED OVER THE GREAT BASIN. MOISTURE GETS PULLED UP THE WESTERN SIDE OF THE RIDGE AND THEN SLOWLY ENTRAINED. MAIN TRIGGER STILL LOOKS LIKE AFTERNOON HEATING SO STORMS WILL FAVOR THE HIGHER TERRAIN. FRIDAY NIGHT-SUNDAY: A DEEPENING TROUGH OF LOW PRESSURE ALONG THE WEST COAST AND COMES ONSHORE FRIDAY NIGHT-SATURDAY. THIS TIGHTENING SW FLOW ALOFT WILL HELP TO PULL SIGNIFICANT MOISTURE FROM HURRICANE JIMENA INTO THE SOUTHWESTERN STATES. THERE IS STILL SOME UNCERTAINTY IF THE BRUNT OF THIS MOISTURE WILL BE PULLED OVER THIS FORECAST AREA. THE LATEST MODELS SHOW THE BEST CHANCE FOR WIDESPREAD PRECIPITATION WILL BE LATE SATURDAY INTO SUNDAY AS THE TROUGH PASSES. MONDAY: FLOW VEERS TO WEST WITH SOME COOL ADVECTION EXPECTED WITH THE TROUGH PASSAGE. DRIER AIR PUSHES OVER THE REGION. THIS TIMING IS STILL SOMEWHAT UNCERTAIN. && .AVIATION... VFR CONDITIONS WILL BE THE RULE ACROSS THE REGION TONIGHT AND TUESDAY. HOWEVER...SMOKE ORIGINATING FROM FIRES IN SOUTHERN CALIFORNIA WILL LIMIT VISIBILITY AT FLIGHT LEVELS ABOVE 4000 FT AGL NORTH OF A K4HV-KMTJ-KGUC LINE. IN ADDITION...ISOLATED THUNDERSTORMS OVER THE CENTRAL AND SOUTHERN MOUNTAINS OF COLORADO WILL GENERATE STRONG OUTFLOW WINDS TO 45 MPH AT TIMES THROUGH 2100 MDT. SMOKE WILL DISSIPATE OVER THE AREA LATE TONIGHT. && .FIRE WEATHER... CRITICAL FIRE WEATHER CONDITIONS NO LONGER EXIST AS RELATIVE HUMIDITY HAS BEGUN TO RECOVER. BEFORE SUNSET...THE GUSTY SURFACE WINDS TO 25 MPH HAVE ENDED AT MANY LOCATIONS. GIVEN CURRENT CONDITIONS...WILL CANCEL THE RED FLAG WARNING. && .GJT WATCHES/WARNINGS/ADVISORIES... .CO...NONE. .UT...NONE. SHORT TERM.....NL LONG TERM......EH+JOE AVIATION.......NL FIRE...........PF
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 755 PM MDT MON AUG 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- 755 PM MDT MON AUG 31 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT... NO HAZARDOUS WEATHER IS EXPECTED FOR THE REMAINDER OF THE NIGHT. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY... ISOLATED MOUNTAIN THUNDERSTORMS ARE POSSIBLE EACH AFTERNOON AND EVENING TUESDAY THROUGH THURSDAY. THUNDERSTORM COVERAGE WILL INCREASE FRIDAY THROUGH SUNDAY AS ANOTHER PACIFIC STORM APPROACHES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT.
The national radar mosaic for the moment the first event began.
15 drought. Local standard time, as filed.
Drought conditions transitioned across the area from abnormally dry at the beginning of the month to moderate by the end of the month.
Drought conditions transitioned across the area from abnormally dry at the beginning of the month to moderate by the end of the month.
Abnormally dry conditions persisted across the area through the month, with moderate drought developing across southwestern portions by the end of the month.
Abnormally dry conditions persisted throughout the month.
Abnormally dry conditions persisted throughout the month.
Abnormally dry conditions persisted throughout the month.
Abnormally dry conditions persisted throughout the month.
Abnormally dry conditions persisted throughout the month.
Abnormally dry conditions spread across the entire area by the end of the month.
Abnormally dry conditions persisted across most of the area throughout the month.
Abnormally dry conditions developed across mainly southern sections of the area by the end of the month.
Abnormally dry conditions developed across mainly southern sections of 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 Colorado in 2009Every state in 2009This day in weather historyWarnings in Colorado, September 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: 196505, 196506, 196507, 196508, 196509, 196510, 196511, 196512, 196513, 196514, 196515, 196516, 196517, 196518, 196519.