216
FXUS65 KGJT 170538
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1138 PM MDT THU JUL 16 2026
KEY MESSAGES
- EXPECT TERRAIN-BASED SHOWERS AND THUNDERSTORMS EACH AFTERNOON
THIS WEEK, FAVORING THE SAN JUANS, BUT SPREADING NORTH BY THE
WEEKEND.
- LOCALIZED HEAVY RAINFALL WILL HAVE THE ABILITY TO PRODUCE
FLASH FLOODING AND DEBRIS FLOWS IN VULNERABLE TERRAIN,
INCLUDING AREAS NEAR AND DOWNSTREAM OF BURN SCARS.
DISCUSSION
ISSUED AT 1055 PM MDT THU JUL 16 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 FORECAST AREA THIS WEEK.
THIS MOISTURE BRINGS DAILY CHANCES OF SHOWERS AND THUNDERSTORMS
IN THE AFTERNOON AND EVENING THROUGH NEXT WEEK.
CONVECTION ON FRIDAY WILL LOOK SIMILAR TO WHAT WE SAW TODAY
(THURSDAY) AS THE PATTERN REMAINS UNCHANGED. INITIATION WILL BE
FAVORED OVER THE HIGHER TERRAIN BEFORE SPREADING OVER THE
VALLEYS AS OUTFLOWS DEVELOP. LIGHTNING AND HEAVY RAIN WILL BE
THE PRIMARY THREATS, WITH SMALL HAIL AND GUSTY OUTFLOW WINDS UP
TO 35-45 MPH ON THE TABLE AS WELL.
WHILE MOISTURE IS A RELIEF FOR DROUGHT CONDITIONS, IT ALSO
CREATES A RISK OF FLASH FLOODING AND DEBRIS FLOWS, INCLUDING
OVER AREA BURNS SCARS. 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.
COOLER TEMPERATURES:
NEAR-NORMAL TEMPERATURES MADE A COMEBACK ON THURSDAY AND REMAIN
IN THE FORECAST INTO EARLY NEXT WEEK. CURRENT MODEL DATA
SUGGESTS THAT WE COULD SEE TEMPERATURES AROUND FIVE DEGREES
BELOW NORMAL MOVE IN AROUND THE MIDDLE OF NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 528 PM MDT THU JUL 16 2026
STORMY WEATHER CONTINUES FOR THE MAJORITY OF THE REGION. MOST
TERMINALS (ASIDE FROM HDN AND VEL) MAY SEE RAINFALL THIS EVENING
AND/OR TOMORROW AFTERNOON. GUSTY OUTFLOW WINDS UP TO 35 KTS
WILL BE POSSIBLE, AND HIGHER ELEVATION TERMINALS, PARTICULARLY
ASE AND EGE COULD OCCASIONALLY DROP BELOW ILS BREAKPOINTS.
HEAVIER RAIN COULD ALSO DROP VIS TO MVFR, THOUGH AREAS WHERE
THIS WILL OCCUR ARE TOO UNCERTAIN AT THIS TIME, AND THUS VIS
REDUCTIONS HAVE NOT BEEN INCLUDED IN ANY TAF'S.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1138 PM MDT THU JUL 16 2026
THE RADAR IS A BIT MORE ACTIVE LATE THIS EVENING WITH SHOWER
ACTIVITY BUT THE ATMOSPHERE IS STABILIZING AND EXPECT STORMS TO
DISSIPATE THROUGH THE NEXT FEW HOURS...LEAVING CONVECTIVE
DEBRIS CLOUDS THROUGH SUNRISE. THE MOISTURE IN PLACE WHICH WILL
ONCE AGAIN ALLOW CONVECTION TO BLOSSOM BY MIDDAY OVER THE
TERRAIN WITH THE FLOW CARRYING THESE STORMS TO THE SOUTHWEST
THROUGH THE EVENING AND IMPACTING THE VALLEY/TAF LOCATIONS.
GUSTY OUTFLOW WINDS AND LOCALLY HEAVY RAIN WILL BE THE MAIN
CONCERN WITH STORMS. THERE IS A LOW PROBABILITY OF MVFR
OCCURRING DUE TO VISIBILITY RESTRICTIONS IN THE HEAVIER SHOWERS
OTHERWISE VFR PREVAILS.
HYDROLOGY
ISSUED AT 1235 PM MDT THU JUL 16 2026
AN ANOMALOUS PLUME OF MOISTURE CONTINUES TO ROTATE INTO UTAH
AND WESTERN COLORADO THIS AFTERNOON, WITH A SLIGHT UPTICK
COMPARED TO YESTERDAY. THE SAN JUANS REMAIN A BULLSEYE IN
PRECIPITATION FORECASTS THIS AFTERNOON AND AGAIN ON FRIDAY,
MAINTAINING FLASH FLOOD THREATS REDEVELOPING EACH AFTERNOON.
HOWEVER, AVAILABLE MOISTURE IS HIGHER MOVING WEST INTO UTAH,
WHICH LEAVES THE POTENTIAL FOR ISOLATED STORMS TO PRODUCE HOURLY
RAINFALL RATE OF 1-2 IN. THEREFORE, AREAS OF CONCERN REMAIN
UNCHANGED FROM THE PREVIOUS FORECAST FOR THIS AFTERNOON.
STORMS OVER THE LAST 24 TO 48 HOURS HAVE ONLY HELPED PRIME
LOWER LEVELS OF THE ATMOSPHERE AND SATURATE THE GROUND WHERE
RAIN WAS OBSERVED. SEVERAL LOCATIONS ACROSS SOUTHWEST COLORADO
REPORTED OVER 0.5 INCHES OF RAIN WITHIN 30 MINUTES DURING
YESTERDAY'S CONVECTION; WHICH IS MORE THAN SUFFICIENT TO CREATE
ISSUES IN OUR STEEP, ROCKY TERRAIN ALREADY SUSCEPTIBLE TO FLASH
FLOODING. THIS ENVIRONMENT ALSO TRIGGERS HEIGHTENED AWARENESS
OVER RECENT (OR ACTIVELY BURNING) FIRES, DUE TO THE BURNT
GROUND'S INABILITY OF ABSORBING MOISTURE UNDER HEAVY RAINFALL.
AS SUCH, WE CONTINUE TO EMPHASIZE THE POTENTIAL FOR FLASH
FLOODING AND DEBRIS FLOWS IN THIS REGIME.
AS A REMINDER: 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...TGJT
AVIATION...TGJT
HYDROLOGY...ERW
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