022
FXUS65 KGJT 152344
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
544 PM MDT WED JUL 15 2026
KEY MESSAGES
- EXPECT TERRAIN-BASED SHOWERS AND THUNDERSTORMS EACH AFTERNOON
THIS WEEK, FAVORING THE SAN JUANS, BUT SPREADING NORTH BY THE
WEEKEND.
- LOCALIZED HEAVIER SHOWERS AND STORMS CREATE A RISK OF FLASH
FLOODING AND DEBRIS FLOWS IN VULNERABLE TERRAIN, INCLUDING
AREAS NEAR AND DOWNSTREAM OF BURN SCARS.
- DAYTIME HIGHS COOL THROUGHOUT THE WEEK, RETURNING TO NEAR-
NORMAL FOR MOST AREAS BY FRIDAY.
DISCUSSION
ISSUED AT 1235 PM MDT WED JUL 15 2026
DAILY SHOWERS AND THUNDERSTORMS:
PERSISTENT HIGH PRESSURE ALOFT KEEPS A PLUME OF MOISTURE OVER
MUCH OF THE WEST THROUGH AT LEAST THIS WEEKEND, POTENTIALLY
BEYOND. GUIDANCE KEEPS THE MOST MOISTURE RICH PART OF THIS PLUME
(IN TERMS OF PWAT ANOMALIES) TO OUR WEST, BUT ENSEMBLES PLACE
PWATS OF 130-200% OF NORMAL OVER OUR CWA THIS WEEK. THE ECMWF
ENS AND GFS ENS HAVE CONSISTENTLY SHOWN DIFFERENCES IN THE
MAGNITUDE OF THE ANOMALIES, WITH ECMWF ENS FAVORING A MUCH MORE
MOIST SETUP WITH MAX PWATS CLOSER TO 200% AT TIMES. THIS
MOISTURE BRINGS DAILY CHANCES OF SHOWERS AND THUNDERSTORMS IN
THE AFTERNOON AND EVENING. THESE CHANCES FAVOR SOUTH OF I-70
TODAY, BUT OVER THE NEXT FEW DAYS COVERAGE OF CHANCES SPREAD
NORTH ACROSS THE CWA. STORMS MOVING ACROSS THE SAN JUAN
MOUNTAINS THIS AFTERNOON HAVE PRODUCED MEASURABLE PRECIPITATION
AND WETTING RAIN, BUT MORE NORTHERN AREAS RECEIVING THEIR FIRST
PUSH OF MOISTURE COULD INITIALLY SEE A MIX OF RAIN REACHING THE
GROUND AND VIRGA/GUSTY OUTFLOW WINDS. WHILE MOISTURE IS A RELIEF
FOR DROUGHT CONDITIONS, IT ALSO CREATES A RISK OF FLASH
FLOODING AND DEBRIS FLOWS, INCLUDING OVER THE BURNS SCARS OF THE
GOLD MOUNTAIN, FERRIS, AND BABYLON FIRES. THE HYDROLOGY SECTION
BELOW DISCUSSES THIS RISK IN GREATER DETAIL. THESE STORMS CAN
DEVELOP QUICKLY, SO BE SURE TO MONITOR THE FORECAST AND HAVE A
WAY TO RECEIVE WEATHER ALERTS, ESPECIALLY IF YOU ARE VISITING OR
RESIDE BELOW TERRAIN THAT IS VULNERABLE TO FLASH FLOODING,
INCLUDING DOWNSTREAM OF ACTIVE FIRES.
TEMPERATURES SHOULD FALL BY AT LEAST A FEW DEGREES DURING THE
REMAINDER OF THIS WEEK THANKS TO INCREASED CLOUD COVER DURING
PEAK HEATING. GUIDANCE CONTINUES TO FAVOR ANOTHER DROP IN
TEMPERATURES NEXT WEEK, POTENTIALLY LEADING TO WIDESPREAD BELOW
NORMAL TEMPERATURES. HOWEVER, THIS IS LARGELY DEPENDENT ON HOW
THE HIGH PRESSURE ALOFT SHIFTS.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 541 PM MDT WED JUL 15 2026
EXPECT MOSTLY VFR CONDITIONS THROUGH THE TAF PERIOD. THE
EXCEPTION WILL BE BRIEF PERIODS OF MVFR ASSOCIATED WITH
THUNDERSTORMS AT TAF SITES ALONG AND SOUTH OF I-70 UNTIL 03Z.
WINDS IN THE VICINITY OF ANY SHOWERS OR THUNDERSTORMS WILL BE
VARIABLE GUSTING 35 TO 50 KTS. OTHERWISE, LOOK FOR LIGHT WINDS
GENERALLY WESTERLY TO NORTHERLY THROUGH THE AFTERNOON BECOMING
LIGHT DRAINAGE WINDS AFTER 03Z.
TOMORROW WILL BE A RINSE AND REPEAT OF WHAT WE SAW TODAY, BUT
COVERAGE OF SHOWERS AND STORMS WILL INCREASE. THE HIGHEST
PROBABILITY OF IMPACTS AT THE TERMINALS FALLS BETWEEN 20Z-03Z.
HYDROLOGY
ISSUED AT 1235 PM MDT WED JUL 15 2026
AN ANOMALOUS PLUME OF MOISTURE CONTINUES TO ROTATE INTO UTAH
AND WESTERN COLORADO THIS AFTERNOON, AS AN ELONGATED AREA OF
HIGH PRESSURE SHIFTS INTO THE SOUTHWESTERN CONUS. FOR TODAY,
STEERING WINDS OVERHEAD ARE NORTHERLY, PROVIDING A UNIQUE STORM
MOTION FOR THE GJT FORECAST AREA. IN ADDITION, OUR SOUTHERN
ZONES AND MOST OF EASTERN UTAH CONTAIN HIGHER AMOUNTS OF
MOISTURE, SO AS STORMS GENERALLY BUILD AND SHIFT SOUTH, THEY'RE
MOVING INTO JUICIER ENVIRONMENTS.
EVEN THOUGH THIS SOURCE OF MOISTURE IS A GREAT RELIEF TO THE
DROUGHT STRICKEN WEST, EXCESSIVE RAINFALL RETURNS THE CONCERNS
OF FLASH FLOODING AND DEBRIS FLOWS OVER RECENT (OR EVEN ON
GOING) BURN SCARS. 18Z'S SOUNDING ALSO SHOWS WEAK FLOW
THROUGHOUT THE ATMOSPHERIC COLUMN, WHICH WILL RESULT IN SLOW
MOVING THUNDERSTORMS THIS AFTERNOON. THE COMBINATION OF
INCREASED MOISTURE AND SLOW STORM MOTION FURTHER ELEVATES THE
CONCERN FOR EXCESSIVE RAINFALL IN LOCALIZED AREAS. THE SAN
JUAN'S ARE A BULLSEYE IN PRECIPITATION FORECASTS OVER THE NEXT
SEVERAL DAYS, MAINTAINING FLOOD THREATS REDEVELOPING EACH
AFTERNOON. DUE TO THE PROLONGED PERIOD OF ANOMALOUSLY HIGH
MOISTURE, OVER AREAS WITH SENSITIVE BURN SCARS, WE WANT TO
EMPHASIZE THE POTENTIAL FOR FLASH FLOODING AND DEBRIS FLOWS IN
THIS REGIME. WE'RE EXPECTING AN UPTICK IN MOISTURE CONTENT
ACROSS THE ENTIRE REGION ON THURSDAY, WHICH FAVORS A HIGHER
LIKELIHOOD OF WETTING RAIN WITH BURSTS OF HEAVY RAIN IN
LOCALIZED STORMS.
FOR 2026 FIRES, WE HAVE YET TO TEST THEIR SUSCEPTIBILITY TO
HANDLE RAINFALL. THEREFORE, WE WANT TO INCREASE OUR MESSAGING OF
THE POTENTIAL HAZARDS AT PLAY DOWNSTREAM NEARBY FIRES. KEEP AN
EYE ON OUR FORECASTS THROUGH THE END OF THE WEEK AND STAY TUNED
FOR UPDATED HYDRO ALERTS IF VISITING OR IF YOU RESIDE BELOW
VULNERABLE TERRAIN TO FLASH FLOODING AND/OR DEBRIS FLOWS. STORMS
ACROSS THE WEST DEVELOP QUICKLY, LEAVING LITTLE ROOM FOR LEAD
TIME IN FLASHY TERRAIN.
GJT WATCHES/WARNINGS/ADVISORIES
CO...NONE.
UT...NONE.
DISCUSSION...GF/TGJT
AVIATION...TGJT
HYDROLOGY...ERW
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