An embedded disturbance within a southerly flow of subtropical moisture across the region produced areas of heavy rainfall and isolated severe thunderstorms in portions of western Colorado.
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.
An embedded disturbance within a southerly flow of subtropical moisture across the region produced areas of heavy rainfall and isolated severe thunderstorms in portions of 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 18, 2:08 PM MST, 2 hours 46 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 308 PM MDT MON JUL 18 2011 .SHORT TERM...TONIGHT THROUGH THURSDAY... ATMOSPHERE REMAINS QUITE MOIST WITH GOOD INSTABILITY UNDER AFTERNOON HEATING. STORM MOTION IS SLOWER THAN FORECASTED THIS MORNING...TO THE N-NE AT AROUND 10-15 MPH. THIS RAISES FLASH FLOOD CONCERNS. ONE AREA OF CONCERN IS THE SW SIDE OF THE UNCOMPAHGRE PLATEAU WHERE THUNDERSTORMS HAVE FORMED AND REFORMED SINCE LATE MORNING. THESE HEAVIER SHOWERS ARE FLOWING INTO THE SAN MIGUEL RIVER. STORMS ACROSS THE NORTHERN CWA ARE MOVING FASTER AND THUS HAVE LESS CHANCE OF RUNOFF PROBLEMS. AS WE SAW IN NUCLA YESTERDAY...LOCALIZED STRONG OUTFLOW WINDS UP TO 60 MPH ARE POSSIBLE. THESE WILL BE SHORT- LIVED AND VERY LOCALIZED AND THEREFORE VERY HARD TO CAPTURE WITH RADAR. WITH WBZ AT 15.6KFT...PEA-SIZE HAIL WILL BE POSSIBLE IN THE HIGHEST ELEVATIONS...BUT DON'T EXPECT THIS TO BIAS THE RADAR PRECIPITATION AMOUNTS TOO MUCH. MOST STORMS WILL END BY MIDNIGHT BUT A FEW STORMS COULD GO INTO THE EARLY MORNING HOURS...ESPECIALLY SOUTH WHERE THE MOISTURE IS DEEPEST. TUESDAY...A DISTURBANCE THAT IS CURRENTLY IN SOUTHERN AZ-NM WILL WORK INTO THE FOUR-CORNERS AREA IN THE MORNING. THIS WILL PROVIDE UPPER LEVEL SUPPORT FOR WIDESPREAD SHOWERS AND STORMS. THE LATEST MODELS PRODUCES A LARGE AREA OF UPPER LEVEL DIVERGENCE FROM CORTEZ NORTH TO ABOUT RANGELY DURING THE AFTERNOON AND EARLY EVENING. TUESDAY NIGHT...UNUSUALLY STRONG WEST COAST TROUGH PASSES TO OUR NORTH. THIS WILL USHER IN A DRIER AIRMASS ACROSS THE NORTHERN FORECAST AREA. WEDNESDAY-THURSDAY...WEST COAST TROUGH REMAINS ACTIVE AND PRODUCES A DRIER SW FLOW OVER OUR NORTHERN CWA. DEEPER MOISTURE REMAINS IN PLACE ACROSS THE S AND SE PORTIONS OF THE FORECAST AREA. DIURNAL TEMPERATURE SPREAD WILL INCREASE ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY... WESTERN TROF/EASTERN RIDGE WILL BE THE UPPER AIR PATTERN BY LATE IN THE WEEK WITH THE NORTHWEST CONUS COOLER THAN NORMAL AND THE SOUTHEAST STATES UNDER EXTREME HEAT THAT WILL BE SHIFTING OUT OF THE PLAINS. THIS WILL LEAVE A STRONGER SOUTHWEST FLOW OVER THE GREAT BASIN AND DRIER CONDITIONS ARE EXPECTED AS THE MOISTURE PLUME IS SHIFTED MOSTLY EAST OF THE ROCKIES AND THINNED OUT BY THE WEEKEND. PRECIPITABLE WATER VALUES ALMOST DROP IN HALF FOR FRIDAY...WHICH HAS BEEN A CONSTANT TREND IN MODELS THE PAST FEW RUNS...LINGERING SOMEWHAT ACROSS THE SOUTHERN CWA AND THE CURRENT TREND OF SCATTERED CONVECTION IN THE SAN JUANS AND ISOLATED DIVIDE THUNDERSTORMS LOOKS ON TRACK. WITH DRIER AIRMASS MOVING IN FROM THE CENTRAL GREAT BASIN TEMPERATURES SHOULD RESPOND BY WARMING TO OR SLIGHTLY ABOVE NORMAL. OVER THE WEEKEND THE LAST BIT OF ENERGY IN THE TROF OVER THE PACIFIC NORTHWEST LIFT/S NORTHEAST INTO CENTRAL CANADA AND ALLOWS THE SUB-TROPICAL RIDGE TO WEDGE IT/S WAY BACK TO THE WEST COAST...CENTERING NEAR THE 4 CORNERS REGION BY EARLY MONDAY. THE HOT NATURE OF THIS RIDGE SHOULD KEEP TEMPERATURES AT ABOVE NORMAL LEVELS INTO EARLY NEXT WEEK. AS FOR MOISTURE THIS RIDGE SHOULD AGAIN ABSORB MONSOONAL MOISTURE AND CONTINUE TO RECYCLE IT FOR AN INCREASE IN AFTERNOON CONVECTION...BUT THERE DOES NOT SEEM TO BE A CLEAR SIGNAL WHEN THIS WILL HAPPEN LOOKING AT PRECIPITABLE WATER AND MOISTURE FIELDS FROM LONGER RANGE MODELS. FOR NOW WILL CONTINUE THE TREND OF DIURNAL THUNDERSTORMS ALONG THE DIVIDE...BUT MORE FAVORED IN THE SOUTHERN MOUNTAINS...CLOSER TO THE MOISTURE PLUME. && .AVIATION... SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THE EVENING HOURS. MVFR CONDITIONS CAN BE EXPECTED NEAR THESE STORMS WITH ISOLATED IFR CONDITIONS POSSIBLE WITH THE STRONGER CELLS. SHOWERS AND THUNDERSTORMS WILL DECREASE IN BOTH STRENGTH AND COVERAGE AFTER MIDNIGHT WITH ONLY LOCALIZED MVFR CONDITIONS POSSIBLE. ANOTHER ROUND OF SHOWERS AND STORMS WILL BEGIN LATE TUESDAY MORNING BECOMING WIDESPREAD IN THE AFTERNOON. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && SHORT TERM......JOE LONG TERM.......DP AVIATION........TGJT
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 602 AM MDT MON JUL 18 2011 COZ001>014-017>023-UTZ022>025-027>029-191202- 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- 602 AM MDT MON JUL 18 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT... MONSOONAL MOISTURE WILL CONTINUE ACROSS THE FORECAST AREA TODAY. EXPECT SHOWER AND THUNDERSTORM ACTIVITY TO INCREASE DURING THE DAY AND CONTINUE INTO THE EVENING. LOCALLY HEAVY RAIN IS POSSIBLE WITH THESE STORMS. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY... A MONSOONAL SURGE WILL CONTINUE TO BRING INCREASED MOISTURE ACROSS THE AREA THROUGH THE MIDDLE OF THE WEEK FOR SHOWERS AND THUNDERSTORMS EACH AFTERNOON AND EVENING. LOCALLY HEAVY RAIN IS POSSIBLE WITH SOME OF THESE STORMS. A DRIER SOUTHWEST FLOW WILL DEVELOP BY THURSDAY FOR A DOWNTURN IN CONVECTIVE ACTIVITY THROUGH THE END OF THE WEEK. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
542 PM MDT MON JUL 18 2011
COZ004-005-190030-
ELKHEAD AND PARK MOUNTAINS CO-UPPER YAMPA RIVER BASIN CO-
542 PM MDT MON JUL 18 2011
...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN ROUTT COUNTY UNTIL 630
PM MDT...
AT 539 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 7 MILES EAST OF OAK CREEK...OR 43 MILES SOUTHEAST
OF CRAIG...MOVING NORTH AT 15 MPH.
HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.
THIS STORM WILL BE NEAR...
OAK CREEK AROUND 550 PM MDT.
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.
TORRENTIAL 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 4011 10666 4010 10701 4047 10707 4048 10665
4046 10664 4035 10665 4034 10663
PFThe Grand Junction radar (KGJX), 102 km away, was scanning. The volume nearest the first event began at 23:54 UTC.
4 heavy rain, 2 flash flood, 1 tornado, 1 thunderstorm wind. Local standard time, as filed.
A rainfall of total of 1.48 inches was measured within 60 minutes at the Crown RAWS weather station.
Ranfall of 0.70 of an inch fell within 60 minutes and resulted in minor flooding.
Over a third of an inch of rain fell within 30 minutes.
Flash floods across Highway 145 deposited mud and other debris up to a foot deep on the road and adjacent roads. Highway 145 was closed for about an hour while the road was cleared of debris. Additionally, the water treatment facility was shut down by the heavy influx of water and debris.
A flash flood deposited mud up to 6 feet deep covering a 100 foot section of TR Road 630, the main road to Ophir. The road was closed for about 8 hours as heavy equipment was used to remove the mud and other debris from the road.
A tornado was observed by several people as it moved over open country. The tornado was located just over a mile west of Highway 160. Some cottonwood trees had limbs broken off.
A rainfall total of 0.74 within 30 minutes resulted in minor street flooding.
Outflow winds from a thunderstorm resulted in violent shaking of a mobile home. No damage was reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2011Every state in 2011This day in weather historyThe tornado archive for Colorado, 2011Warnings 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: 331354, 331350, 331359, 331348, 331324, 331280, 331323, 331281.