346
FXUS65 KGJT 041758
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1158 AM MDT THU SEP 4 2025
KEY MESSAGES
- TEMPERATURES TREND AROUND 5 DEGREES ABOVE NORMAL TODAY BEFORE
A COOLER AND MORE ACTIVE STORM SYSTEM MOVES IN BY FRIDAY.
- SCATTERED TO WIDESPREAD SHOWERS AND THUNDERSTORMS ACROSS THE
SOUTHERN MOUNTAINS TODAY BECOME MORE WIDESPREAD ACROSS THE
REGION THROUGH THE WEEKEND.
- THE POTENTIAL FOR BURN SCAR FLASH FLOODING INCREASES FRIDAY INTO
THE WEEKEND.
SHORT TERM /THROUGH FRIDAY/
ISSUED AT 442 AM MDT THU SEP 4 2025
SATELLITE IMAGERY SHOWS THE MOIST PLUME EXTENDING NORTH ACROSS
ARIZONA, WESTERN UTAH, NORTHERN NEVADA INTO OREGON, BUT IS
INDICATING THE PLUME TURNING TO THE NORTHEAST COMING OUT OF ARIZONA
INTO THE FOUR CORNERS AREA AS THE WEAK LOW DISTURBANCE MOVES INTO
UTAH. IT ALSO SHOWS HIGH PRESSURE CENTERED OVER DURANGO MEXICO IS
PULLING THE MOISTURE FROM LORENA MORE TO THE EAST MOSTLY SOUTH OF
THE MEXICAN BORDER. THIS IS IN GOOD AGREEMENT WITH THE ENSEMBLE MEAN
SOLUTIONS, BUT THE DETERMINISTIC MODELS ARE TENDING TO STRIP A BIT
OF THIS PLUME OFF TO THE NORTHWEST INTO WESTERN ARIZONA AND SOCAL
THAT WILL FEED NORTH INTO UTAH AND NORTHWESTERN COLORADO THIS
WEEKEND. GUIDANCE HAS BACKED OFF ON THE QPF THROUGH THE WEEKEND WITH
MOST OF THE HEAVIER PRECIP STAYING TO THE SOUTH OF I-70. THERE IS
NOT A LOT OF CONFIDENCE EITHER WAY, BUT THE SATELLITE IMAGERY IS
PRETTY CONVINCING. STAY TUNED AS THE CONDITIONS MAY CHANGE OVER THE
NEXT DAY OR TWO.
THAT BEING SAID, LOOK FOR INCREASING CLOUDS FROM THE SOUTHWEST WITH
SCATTERED TO WIDESPREAD SHOWERS AND THUNDERSTORMS FIRING UP OVER THE
SOUTHERN MOUNTAINS FROM LATE MORNING THROUGH THE AFTERNOON EXTENDING
NORTH TO THE I-70 CORRIDOR AND THE TAVAPUTS BY EVENING WITH PRIMARY
THREATS BEING LIGHTNING, GUSTY OUTFLOW WINDS AND LOCALIZED HEAVY
RAIN. CONVECTIVE ACTIVITY WILL BECOME MORE ISOLATED TO SCATTERED
OVERNIGHT INTO FRIDAY, BUT WILL PICK UP AGAIN FRIDAY AFTERNOON.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
ISSUED AT 228 PM MDT WED SEP 3 2025
MONSOONAL MOISTURE REMAINS IN PLACE THROUGH THE WEEKEND WITH
SCATTERED TO WIDESPREAD SHOWERS AND STORMS LIKELY. WEAK
NORTHWESTERLY FLOW FOLLOWS THE SHORTWAVE'S PASSAGE ON THURSDAY
NIGHT HELPING PRECIPITATION CHANCES SPREAD NORTHWARD. IT MAY
TAKE SOME TIME FOR THE LOWER LEVELS TO SATURATE SO THE HIGHEST
PRECIPITATION CHANCES REMAIN SOUTH OF I-70, BUT AS SOON AS THE
VERTICAL COLUMN MOISTENS IT WILL BE GAME ON AREA WIDE. IT'S
LOOKING LIKE THIS WILL HAPPEN ON SATURDAY, BUT THERE MAY BE
REFINEMENTS IN THE FORECAST OVER THE NEXT COUPLE OF DAYS AS THE
CAMS ARE INTRODUCED INTO MODEL BLENDS. WITH DRIER NEAR-SURFACE
AIR TO WORK THROUGH NORTH OF I-70 ON FRIDAY, ANY STORMS THAT
DEVELOP WILL BE CAPABLE OF PRODUCING GUSTY OUTFLOW WINDS UP TO
45 MPH. SOUTH OF I-70, GUSTY OUTFLOW WINDS WILL BECOME LESS
LIKELY FRIDAY AND BEYOND.
THE PEAK OF THIS MONSOONAL PUSH OCCURS ON SATURDAY WITH
WIDESPREAD SHOWERS AND STORMS BECOMING MORE LIKELY. A WEAK
SHORTWAVE IS ALSO PROGGED TO PASS THROUGH LATER IN THE DAY ON
SATURDAY WHICH COULD BE ENOUGH TO SUPPORT A FEW STRONGER STORMS
CAPABLE OF PRODUCING LARGE HAIL UP TO 1" IN DIAMETER. THERE IS
ALSO THE POTENTIAL FOR HEAVY RAINFALL WITH THE ADDED SYNOPTIC
SUPPORT TEAMING UP WITH PWATS 150- 175% OF NORMAL. THE ONE
CAVEAT HERE IS THAT THE GEFS IS RUNNING DRIER ACROSS NORTHWEST
COLORADO ON SATURDAY SO THAT WILL BE SOMETHING TO WATCH. THIS
SIGNAL IS NOT PRESENT IN THE ECMWF ENS.
IF HEAVY STORMS/DOWNPOURS TRACK OVER RECENT BURN SCARS,
LOCALIZED FLASH FLOODING AND DEBRIS FLOWS ARE POSSIBLE THROUGH
SUNDAY.
MOISTURE BEGINS LIFTING NORTH AWAY FROM THE LOCAL AREA ON
SUNDAY INTO MONDAY. MODEL GUIDANCE DIVERGES BEYOND THIS
TIMEFRAME SO WE WILL HAVE TO WAIT AND SEE WHICH DIRECTION THE
MODELS TREND OVER THE NEXT COUPLE OF DAYS. HIGH TEMPERATURES
REMAIN SEASONABLE THROUGH MUCH OF THE EXTENDED FORECAST.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1146 AM MDT THU SEP 4 2025
SHOWERS ARE ONGOING IN THE SOUTHERN HALF OF THE REGION. COVERAGE
OF SHOWERS SHOULD INCREASE DURING THE AFTERNOON, AND THERE IS
POTENTIAL FOR SOME THUNDERSTORMS AS WELL. MOST OF THE
PRECIPITATION SHOULD REMAIN NEAR OR SOUTH OF I-70. RAIN IS
EXPECTED TO CONTINUE THROUGH THE OVERNIGHT HOURS. DROPS TO MVFR
CONDITIONS AND MEETING ILS BREAKPOINTS ARE THE MAIN CONCERNS
WITH THIS PRECIPITATION. GUSTY WINDS ARE POSSIBLE NEAR SHOWERS
AND THUNDERSTORMS.
GJT WATCHES/WARNINGS/ADVISORIES
CO...NONE.
UT...NONE.
SHORT TERM...DB
LONG TERM...KAA
AVIATION...TGJT
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