290
FXUS65 KGJT 041812
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1212 PM MDT SAT OCT 4 2025
KEY MESSAGES
- BREEZY SOUTHWESTERLY WINDS WITH GUSTS OF 30-40 MPH CONTINUE
TODAY, WITH LOCALLY STRONGER WINDS POSSIBLE PARTICULARLY
AROUND THE FOUR CORNERS.
- SHOWERS AND STORMS ASSOCIATED WITH THE APPROACHING LOW
PRESSURE CONTINUE THROUGH THIS EVENING. LIGHT SNOW IS POSSIBLE
ABOVE 9K FEET.
- TEMPERATURES DROP BELOW NORMAL TODAY AND TOMORROW, THEN
REBOUND TO NEAR NORMAL VALUES MONDAY AS WARMER AND MORE
SEASONABLE CONDITIONS RETURN.
SHORT TERM /THROUGH SUNDAY/
ISSUED AT 306 AM MDT SAT OCT 4 2025
THE CENTER OF THE APPROACHING LOW IS CURRENTLY CENTERED AROUND THE
NEVADA/ARIZONA/UTAH BORDER. DIFFLUENT FLOW ALOFT OUT AHEAD OF THIS
LOW, ALONG WITH SOME ENHANCED JET DYNAMICS, CONTINUES TO PROVIDE
AMPLE LIFT TO KEEP SHOWERS AND THUNDERSTORMS GOING ACROSS THE
REGION. ACTIVITY HAS, FOR THE TIME BEING, TAPERED OFF FOR AREAS
NORTH OF I-70, BUT HAS FILLED IN ACROSS SOUTHEAST UTAH AND SOUTHWEST
COLORADO, WHERE THE BEST LIFT AND MOST AMPLE MOISTURE IS CURRENTLY
LOCATED. YESTERDAY EVENING'S 00Z GJT SOUNDING HAD A PWAT OF 0.64,
WHICH IS WELL ABOVE NORMAL FOR THIS TIME OF YEAR, AND DOES FALL
WITHIN THE FORECASTED 150-200% OF NORMAL PWAT VALUES ASSOCIATED WITH
THIS STORM. AND THIS MOISTURE WILL CONTINUE TO INCREASE THROUGH
MIDDAY AS WE REMAIN UNDER MOIST, STRONG SOUTHWESTERLY FLOW. WHILE
THE MOISTURE IS DEFINITELY THERE, AND THESE STORMS HAVE PRODUCED
WETTING RAINS ACROSS THE REGION ALREADY, THEIR QUICK SPEED WILL PUT
A DAMPER ON TOTALS. AREAS THAT SEE TRAINING STORMS, AND TERRAIN
FEATURES THAT FAVOR SOUTHWESTERLY UPSLOPE FLOW, WILL SEE THE BEST
PRECIPITATION ACCUMULATION WITH THIS STORM. THE VAST MAJORITY OF
EASTERN UTAH AND WESTERN COLORADO WILL SEE THIS PRECIPITATION FALL
AS RAIN, BUT AS COOLER AIR MOVES IN ALOFT TODAY, THE HIGHEST
ELEVATIONS COULD SEE SOME SNOW...AT BEST AN INCH OR TWO OF SNOW
ACCUMULATION IS POSSIBLE.
IN ADDITION TO THE INCREASING MOISTURE, WE'RE SEEING INCREASINGLY
STRONG AND GUSTY SOUTHWESTERLY WINDS AHEAD OF THE LOW. SOME OF THIS
IS DUE TO DEEP MIXING STILL TAPPING INTO THE 90-100 KNOT JET ALOFT
AND MIXING DOWN THE STRONGER WINDS, AND SOME IS DUE SOLELY TO THE
SURFACE PRESSURE GRADIENT CONTINUING TO TIGHTEN. WIDESPREAD GUSTS OF
30-40 MPH ARE EXPECTED INTO THIS AFTERNOON, WITH POCKETS OF STRONGER
GUSTS ABOVE 45 MPH. SOME OF THE LOWER VALLEYS IN THE FOUR CORNERS
REGION ARE PARTICULARLY FAVORED TO SEE THESE HIGHER END WINDS, AND A
WIND ADVISORY REMAINS IN EFFECT FOR THESE AREAS FROM 10 AM MDT TO 5
PM MDT TODAY. WINDS WILL FINALLY START TO TAPER OFF THIS EVENING
THANKS TO THE SURFACE COLD FRONT AND UPPER LEVEL TROUGH AXIS
SWINGING THROUGH DURING THE AFTERNOON. FLOW ALOFT SWITCHES TO
WESTERLY TO NORTHWESTERLY AND FINALLY RELAXES.
TEMPERATURES ARE VERY MILD TONIGHT, THANKS TO THE PRESENCE OF
INCREASED MOISTURE, CLOUDS AND SHOWERS, AND THOSE ELEVATED WINDS.
THE CLOUDS AND PRECIPITATION THIS MORNING WILL SLOW DAYTIME WARMING
CONSIDERABLY, AND THEN THE SURFACE COLD FRONT WILL PUSH THROUGH THIS
AFTERNOON, USHERING IN A MUCH COOLER AIRMASS. ALL IN ALL, TODAY'S
HIGHS WILL RUN A SOLID 10-15 DEGREES BELOW WHAT WE SAW YESTERDAY,
AND RUN 3-5 DEGREES BELOW EARLY OCTOBER NORMS. WITH MUCH DRIER AIR
SWEEPING IN BEHIND THE LOW TONIGHT, CLEAR SKIES AND QUIETER WINDS,
ALONG WITH THAT COOLER AIRMASS, WILL JOIN TO PROMOTE RADIATIONAL
COOLING. GUIDANCE AT THIS POINT ONLY HAS LIMITED AREAS OF BELOW
FREEZING TEMPERATURES TONIGHT, BUT THAT IS SOMETHING TO KEEP AN EYE
ON, PARTICULARLY FOR SOME OF THE HIGHER ELEVATION VALLEYS. THIS
PATTERN OF CLEAR SKIES, LIGHTER WINDS, AND BELOW NORMAL TEMPERATURES
WILL FOLLOW INTO TOMORROW, WHERE A BEAUTIFUL FALL DAY IS IN THE
WORKS FOR MOST AREAS. THE ONE EXCEPTION WILL BE FOR AREAS OF
NORTHEAST UTAH AND NORTHWEST COLORADO, PARTICULARLY CLOSE TO THE
WYOMING BORDER. ENOUGH MOISTURE STICKS AROUND THERE TO KEEP SOME
CLOUDS IN PLACE, AND A FEW WEAK WAVES SWINGING THROUGH COULD TRIGGER
A FEW LIGHT RAIN SHOWERS. THIS WILL ALSO KEEP TEMPERATURES EVEN
COOLER, WITH HIGHS EXPECTED TO BE 5-10 DEGREES BELOW NORMAL.
ELSEWHERE, HIGHS WILL REMAIN 3-5 DEGREES BELOW NORMAL, AND MOST
LOCATIONS WILL SEE ABUNDANT SUNSHINE.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
ISSUED AT 306 AM MDT SAT OCT 4 2025
THE LONG TERM PERIOD WILL START OUT WITH A LONG WAVE TROUGH DRAPED
ACROSS MUCH OF THE INTERMOUNTAIN WEST. THE BEST SUPPORT WILL REMAIN
OVER WYOMING, IDAHO AND MONTANA SO WHILE THERE WILL BE A SLIM CHANCE
FOR A FEW ISOLATED SHOWERS OVER THE NORTHERN MOUNTAINS, QUIET
CONDITIONS WILL BE THE RULE. UPPER LEVEL SUPPORT WILL THEN SHIFT TO
THE PLAINS WHICH WILL CAUSE THE TROUGH TO REMAIN IN PLACE.
EVENTUALLY, A CLOSED LOW WILL FORM IN THE BASE OF THE TROUGH, MONDAY
INTO TUESDAY. BY WEDNESDAY, THE SYSTEM WILL START TRACKING EASTWARD
CAUSING FLOW TO BECOME MORE SOUTHWESTERLY. SOME AVAILABLE MOISTURE
TO THE SOUTH WILL BE ENTRAINED BY THIS FLOW, BRINGING INCREASING
CHANCES FOR PRECIPITATION, ESPECIALLY OVER THE SAN JUANS UP INTO THE
CENTRAL MOUNTAINS. BY LATE IN THE WEEK, A NEW CLOSED LOW DEVELOPS
OFF THE PACIFIC NORTHWEST COAST. THIS WILL BUILD SOME RIDGING INTO
THE FOUR CORNERS AND SOUTHERN ROCKIES. AT THIS POINT, PWATS, WHICH
HAVE BEEN AT OR BELOW NORMAL, WILL START TO CLIMB ONCE MORE AS FLOW
ALOFT DRAWS MOISTURE UP FROM THE SOUTH. SO CHANCES OF MOUNTAIN
SHOWERS OR THUNDERSTORMS, PARTICULARLY OVER THE SOUTHERN RANGES,
REMAINS THROUGH THE END OF THE WEEK. TEMPERATURES ARE EXPECTED TO
GRADUALLY WARM THROUGH THE LONG TERM PERIOD.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1158 AM MDT SAT OCT 4 2025
A PERIOD OF SHOWERS AND THUNDERSTORMS CONTINUE TO LIFT NORTHWARD
ACROSS COLORADO AND EASTERN UTAH THROUGH THE AFTERNOON, AS AN
UPPER LEVEL SYSTEM SLOWLY ADVANCES EASTWARD. THE MAIN IMPACTS
INTO THIS EVENING WITH ANY STORM WILL BE LIGHTNING, GUSTY WINDS
AND LOCALLY HEAVY RAIN. GUSTY WINDS TO 25-35 KNOTS ARE EXPECTED
THROUGH THIS EVENING, BEFORE DIMINISHING FOR MOST ZONES BY
EARLY SUNDAY MORNING. MAINLY EXPECT VFR CIGS, EXCEPT MVFR/IFR
AT TIMES IN HEAVIEST RAIN. MAINLY MVFR VSBY IN AREAS OF
PRECIPITATION.
GJT WATCHES/WARNINGS/ADVISORIES
CO...WIND ADVISORY UNTIL 5 PM MDT THIS AFTERNOON FOR COZ020-021.
UT...NONE.
SHORT TERM...BGB
LONG TERM...TGR/TGJT
AVIATION...TGJT
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