Afternoon thunderstorms once again produced pockets of heavy rainfall with one report of a mud slide in a known problem area. However, some of the storms produced strong outflow winds gusts in the Cortez and Durango areas.
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.
Afternoon thunderstorms once again produced pockets of heavy rainfall with one report of a mud slide in a known problem area. However, some of the storms produced strong outflow winds gusts in the Cortez and Durango areas.
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 10, 10:33 AM MST, 2 hours 27 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 1133 AM MDT SAT AUG 10 2013 .UPDATE... ISSUED AT 1130 AM MDT SAT AUG 10 2013 OPEN DISTURBANCE HAS BEEN LIFTING THROUGH SE UTAH THIS MORNING. ASSOCIATED CLOUDS ARE SPREADING NE INTO THE CENTRAL CWA LATE MORNING. A FEW THUNDERSTORMS FORMED NEAR LAKE POWELL THIS MORNING WITH THE FIRST STRONGER STORM FORMING OVER THE PARADOX VALLEY AT 11AM. THIS VALLEY LOCATION SHOWS THE DYNAMICS WITH THIS WAVE. THE 12Z NAM HAS INITIALIZED BETTER THAN THE 06Z BUT STILL LOOKS RELATIVELY HEAVY HANDED WITH ITS QPF FIELD FOR THIS AFTERNOON. THE DISTURBANCE LIFTS INTO THE NORTHERN CWA AND WEAKENS THROUGH THE AFTERNOON. THE BEST FORCING STILL LOOKS LIKE EASTERN UTAH AND THE SAN JUAN MTNS. A RELATIVELY DRY NEAR SURFACE LAYER AND CLOUD BASES EXPECTED TO FORM AROUND 15-16KFT MSL THREATENS MORE WIND THAN RAIN OUT OF ANY ONE STORM. STORM MOTION IS TO THE NE AT 15KTS ALSO INDICATING OUTFLOW WINDS COULD BE STRONG THIS AFTERNOON. && .SHORT TERM...(TODAY THROUGH SUNDAY) 410 AM MDT SAT AUG 10 2013 STAGNANT PATTERN FEATURING A PERSISTENT LOW OVER THE PACIFIC NORTHWEST AND HIGH PRESSURE CENTERED OVER WEST TEXAS WILL REMAIN LARGELY UNCHANGED TODAY. BETWEEN THESE CIRCULATIONS FLOW WILL CONTINUE FROM THE SOUTHWEST CARRYING MODERATELY MOIST MONSOONAL AIR ACROSS THE REGION. 00Z/SAT SOUNDING AT KGJT WAS DOWN TO 0.52 INCHES BUT MODELS SUGGEST MOISTURE SHOULD INCREASE SLIGHTLY TODAY...ESPECIALLY ACROSS THE SOUTH. MODELS ALSO INDICATED A DISTURBANCE MOVING ACROSS NM AND AZ SHOULD BEGIN GENERATING SHOWERS AND THUNDERSTORMS ACROSS THE SOUTH THIS MORNING. THEREAFTER...DAYTIME WARMING SHOULD BE SUFFICIENT TO GENERATE NUMEROUS STORMS OVER THE MOUNTAINS THIS AFTERNOON WITH SCATTERED STORMS MOVING NORTHWARD OVER ADJACENT VALLEYS. EXPECT AFTERNOON HIGHS WILL CONTINUE TO RUN A FEW DEGREES BELOW NORMAL IN RESPONSE TO CLOUDS AND SHOWERS. SATURDAY NIGHT THROUGH SUNDAY...STILL LITTLE CHANGE IN THE WEATHER PATTERN OVER OUR CWA DURING THIS PERIOD AS UPPER HIGH IS EXPECTED TO REMAIN CENTERED OVER TX AND UPPER LOW PRESENTLY CENTERED ALONG THE NORTHERN CA COAST TO DRIFT SLOWLY NORTHWARD. POSSIBLE EMBEDDED WEAK DISTURBANCES IN THE FLOW CROSSING OUR CWA. OTHER THAN THAT... EXPECT SOLAR HEATING TO BE THE PRIMARY FIRING MECHANISM. LITTLE CHANGE IN TEMPERATURES EXPECTED. PRECIPITABLE WATER VALUES ACROSS OUR CWA EXPECTED TO CONTINUE TO GENERALLY RANGE FROM ABOUT A HALF INCH TO 0.75 OF AN INCH...SO THERE SHOULD BE A MINIMAL THREAT OF FLOODING FROM STORMS. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) 410 AM MDT SAT AUG 10 2013 ON MONDAY THE MODELS INDICATE A SHORTWAVE DISTURBANCE RIPPLING UP THE BACK SIDE OF UPPER RIDGE ACROSS OUR CWA...WHICH SHOULD ENHANCE ANY CONVECTION WHICH DEVELOPS. MODELS ALSO INDICATING SOME WEAK JET DYNAMICS INTO THE SOUTHERN PORTION OF OUR CWA. TIMING AND POSITION OF THE SHORTWAVE VARY FROM MODEL TO MODEL...SO WILL CONTINUE TO KEEP THE TIMING OF THUNDERSTORMS RATHER GENERIC AND NOT YET REFERENCE THUNDERSTORM/PRECIPITATION INTENSITY. NAM STILL SHOWING NOTICEABLE INCREASE OF MID LEVEL MOISTURE INTO OUR CWA ON MONDAY...WHILE NOT SO MUCH WITH THE OTHER MODELS. INTERESTINGLY... NAM IS ONLY INDICATING SLIGHTLY HIGHER PRECIPITABLE WATER VALUES THAN THE OTHER MODELS. MAX TEMPS ON MONDAY SHOULD BE A TAD LOWER THAN SUNDAY DUE TO MORE CLOUDS AND A FEW MORE THUNDERSTORMS THAN SUNDAY. BY TUESDAY...HIGH PRESSURE BEGINS TO EXPAND WESTWARD FROM TX ACROSS NM AND AZ. THIS SHIFT IN PATTERN WILL RESULT IN A PERIOD OF DRYING DURING THE LATTER PART OF THE WEEK. HOWEVER...EXPECT RESIDUAL MOISTURE WILL FUEL SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS...MAINLY DURING THE AFTERNOON...THOUGH THERE WILL BE A STEADY DECLINE IN COVERAGE AS THE WEEK PROGRESSES. DECREASED MOISTURE AND CLOUD COVER WILL ALLOW TEMPERATURES TO RISE TO NEAR NORMAL BY THE END OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING) 1130 AM MDT SAT AUG 10 2013 A DISTURBANCE IS LIFTING SW-NE ACROSS THE CENTRAL-NORTHERN FORECAST AREA THIS AFTERNOON. LIMITED MOISTURE WILL KEEP MOST CLOUD BASES AT 15-16KFT MSL...SO VFR CONDITIONS WILL DOMINATE. SCATTERED SHOWERS AND THUNDERSTORMS OVER THE SOUTHERN MOUNTAINS AND ADJACENT LOWER ELEVATIONS AFTER SUNRISE. THESE STORMS WILL BE CAPABLE OF OBSCURING HIGHER TERRAIN AT TIMES WHILE PRODUCING OUTFLOW WINDS TO 40 MPH ALONG WITH SMALL HAIL AND BRIEF HEAVY RAIN. EXPECT THE USUAL DOWNTURN IN THUNDERSTORM ACTIVITY DURING THE LATE EVENING AND OVERNIGHT AS TEMPERATURES COOL AND THE ATMOSPHERE STABILIZES. MAINLY MOUNTAIN THUNDERSTORMS WILL BEGIN TO FORM AGAIN LATE SUNDAY MORNING. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && UPDATE...JOE SHORT TERM...NL/JRP LONG TERM...JRP/NL AVIATION...JOE
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
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GRAND JUNCTION CO 148 PM MDT SAT AUG 10 2013 COZ019-021-102030- FOUR CORNERS/UPPER DOLORES RIVER CO-SOUTHWEST SAN JUAN MOUNTAINS CO- 148 PM MDT SAT AUG 10 2013 ...SIGNIFICANT WEATHER ADVISORY FOR MONTEZUMA COUNTY UNTIL 230 PM MDT... AT 142 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 16 MILES SOUTHWEST OF CORTEZ...OR 49 MILES WEST OF DURANGO...MOVING NORTHEAST AT 20 MPH. HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE POSSIBLE WITH THIS STORM...ALONG WITH HEAVY RAIN. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... CORTEZ... DOLORES... MANCOS... STONER... IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. BRIEF HEAVY RAIN...MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES. DO NOT DRIVE YOUR VEHICLE ON A FLOODED ROADWAY. LAT...LON 3761 10832 3742 10813 3707 10873 3721 10888 JOE
The Grand Junction radar (KGJX), 197 km away, was scanning. The volume nearest the first event began at 19:59 UTC.
5 thunderstorm wind, 1 debris flow, 1 lightning. Local standard time, as filed.
Thunderstorm winds estimated near 60 mph caused damage to boat docks on the southern end of Vallecito Reservoir. A number of boats were also damaged by the 5 to 6 foot waves which crashed into the docks.
A debris flow induced by heavy rainfall impeded travel on Highway 145 for over an hour.
A power pole was struck by lightning and started on fire.
Another thunderstorm outflow produced strong winds at the La Plata County Regional Airport.
Several large trees were blown down across the Durango area.
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, August 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: 537240, 533660, 533666, 533661, 533662, 533663, 533664.