A persistent light southerly flow aloft with deep subropical moisture over the region resulted in some thunderstorms with heavy rainfall in western Colorado.
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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 persistent light southerly flow aloft with deep subropical moisture over the region resulted in some thunderstorms with heavy rainfall in western Colorado.
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, 1:04 PM MST, 4 hours 26 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 204 PM MDT SUN JUL 31 2011 .SHORT TERM DISCUSSION...TONIGHT THROUGH TUESDAY... A MOIST SOUTHERLY SUBTROPICAL FLOW WILL CONTINUE OVER THE REGION THROUGH THE SHORT TERM. PRECIPITABLE WATER FROM THIS MORNING SOUNDING AT GJT WAS AT 1.2 INCHES. MODEL AND SATELLITE SHOW BEST FLOW AND FORCING REMAINS WEST OF THE FORECAST AREA THROUGH TONIGHT. HOWEVER... WITH ABUNDANT MOISTURE AND DAYTIME HEATING...EXPECT STORMS TO DEVELOP AND CONTINUE INTO THE EVENING HOURS. THE MAIN THREAT WILL BE LOCALLY HEAVY RAIN THROUGH THIS EVENING WITH THE STRONGER STORMS. BASED ON RECENT TREND...HAVE KEPT ISOLATED/SCATTERED SHOWERS AND THUNDERSTORMS CONTINUING OVERNIGHT AND EARLY MONDAY. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL DEVELOP ON MONDAY AS UPPER DISTURBANCES ENHANCE CONVECTION DURING AFTERNOON AND EVENING HOURS. LOCALLY HEAVY RAIN IS POSSIBLE WITH THESE STORMS...BUT EXPECT EXTENSIVE CLOUD COVER TO INHIBIT STRONGER STORMS AND THEREFORE HAVE DECIDED AGAINST ISSUING A FLASH FLOOD WATCH ATTM. STAY TUNED TO LATEST UPDATES ON THIS MATTER. PRECIPITATION WILL DIMINISH TO SLIGHT CHANCE/CHANCE POPS MONDAY NIGHT AND EARLY TUESDAY. FLOW WILL SHIFT A BIT MORE SOUTHWEST WITH ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS EXPECTED TUESDAY AFTERNOON AND EVENING. .LONG TERM DISCUSSION...TUESDAY NIGHT THROUGH SUNDAY. TROUGH OVER THE PACIFIC NORTHWEST AND RIDGE OVER HIGH PLAINS WILL CONTINUE TO DOMINATE WEATHER PATTERN THROUGH THE WORK WEEK. MODELS DO SHOW RIDGE DRIFTING SLIGHTLY WEST INTO THE WEEKEND. WITH LESS FAVORABLE FLOW AND MOISTURE...HAVE CONTINUED TREND FROM PREVIOUS FORECAST SHIFTS TO DECREASE POPS OVER THE AREA AS WEEK PROGRESSES. EXPECT MAINLY CHANCE OF AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS ON WEDNESDAY...WITH DECREASING POPS ON THURSDAY AND SIGNIFICANTLY DRIER ON FRIDAY WITH ONLY A SLIGHT CHANCE OF POPS ALONG THE CONTINENTAL DIVIDE. DRY RIDGE OF HIGH PRESSURE WILL DOMINATE FOR THE WEEKEND WITH MOSTLY SUNNY DAYS AND ONLY A SLIGHT CHANCE OF POPS OVER HIGHER TERRAIN NEAR THE DIVIDE BOTH DAYS WITH SEASONABLE HIGH TEMPERATURES EXPECTED. && .AVIATION... PREDOMINANTLY VFR CONDITIONS THIS AFTERNOON AND TONIGHT ALTHOUGH STRONG STORMS COULD LOWER CIG/VIS TO SCATTERED MVFR CONDITIONS AND ISOLATED IFR CONDITIONS AT TIMES. KTEX AND KASE AIRPORTS HAVE THE HIGHEST CHANCE OF LOWER CIGS AND REDUCED VIS FROM STORMS. FOR OTHER AIRPORTS...GUSTY OUTFLOW WINDS TO 30 KNOTS WILL BE THE PRIMARY THREAT FROM STORMS. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && SHORT TERM...MPM LONG TERM....MPM AVIATION.....MPM
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 600 AM MDT SUN JUL 31 2011 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 SUN JUL 31 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT... SCATTERED SHOWERS AND THUNDERSTORMS...MORE NUMEROUS OVER THE SOUTHERN MOUNTAINS...CAN BE EXPECTED TODAY. LOCAL HEAVY RAIN SHOWERS...FREQUENT CLOUD TO GROUND LIGHTNING...AND GUSTY WINDS TO 35 MPH WILL BE THE COMMON THREATS FROM THUNDERSTORMS. HEAVY RAIN IN THE MOUNTAINS MAY GENERATE SOME MUD DEBRIS FLOW...ESPECIALLY ON HIGHWAY 145 NEAR TELLURIDE AND POSSIBLY OTHER MOUNTAIN HIGHWAYS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY... AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS WILL CONTINUE FOR MUCH OF THE WEEK...ALTHOUGH A DRYING TREND IS EXPECTED TOWARD SATURDAY. LOCALLY HEAVY RAIN HAVE THE POTENTIAL TO GENERATE MUD DEBRIS FLOWS ONTO ROADS AND RISES ALONG STREAMS AND NORMALLY DRY CREEK BEDS OR WASHES WILL BE POSSIBLE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED TODAY OR TONIGHT.
The Grand Junction radar (KGJX), 126 km away, was scanning. The volume nearest the first event began at 00:29 UTC.
1 flash flood. Local standard time, as filed.
Flash flooding occurred along a 5 mile stretch along and near Gypsum Creek Road, with flood waters up to 8 feet deep across one side road. Roads were washed out in places.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2011Every state in 2011This day in weather historyWarnings in Colorado, July 2011
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: 331565.