248
FXUS65 KGJT 130323
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
923 PM MDT SAT SEP 12 2026
KEY MESSAGES
- SHOWER AND STORM CHANCES INCREASE SUNDAY, AND PEAK IN COVERAGE
BY MONDAY, BRINGING IN WIDESPREAD COOL, WET, AND UNSETTLED
WEATHER.
- THERE IS A CHANCE FOR STRONG STORMS OVER THE NEXT FEW DAYS
CAPABLE OF PRODUCING HAIL, GUSTY WIND AND HEAVY RAINFALL.
- DAYTIME HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES ABOVE NORMAL,
BEFORE A SHIFT TO COOLER TEMPERATURES BY MONDAY.
DISCUSSION
ISSUED AT 917 PM MDT SAT SEP 12 2026
SCATTERED STORMS SUNDAY:
SHOWER AND STORM COVERAGE INCREASES TOMORROW AS THE NEXT STRONG PUSH
OF MOISTURE BEGINS TO MOVE IN. PWATS CONTINUE TO CLIMB, WITH VALUES
UPWARDS OF 200% OF NORMAL, WITH THE LIKELY CHANCE OF EXCEEDING THE
75TH PERCENTILE AND APPROACHING, IF NOT SURPASSING THE MAX VALUES
FOR MID SEPTEMBER.
COOLER AND WETTER PATTERN MONDAY AND BEYOND:
BY MONDAY, A DEEP TROUGH BEGINS TO PUSH INTO THE PACNW. DUE TO
CYCLONIC FLOW AROUND A LOW, SOUTHWESTERLY FLOW WILL BE FAVORED OVER
THE SOUTHWESTERN CONUS. THIS MEANS SUBTROPICAL MOISTURE WILL BE
PUSHED FURTHER INLAND, CENTERING THE STRONG PLUME OF MOISTURE OVER
OUR CWA. PWATS CONTINUE TO BE FORECASTED OVER THE 75TH PERCENTILE
FOR THIS TIME OF YEAR, WHICH WILL BE ENOUGH TO PROMPT OUR NEXT
CHANCE FOR WIDESPREAD SHOWERS AND STORMS.
MONDAY IS THE PEAK OF THE MOISTURE, BUT IT MAY BE SO MUCH THAT WE
END UP CLOUDY THEREFORE INHIBITING INSTABILITY. IF THAT HAPPENS WE
WILL SEE MORE STRATIFORM SHOWERS. HOWEVER, IT IS WORTH CONSIDERING
THE DYNAMIC FORCING AT PLAY DURING THIS TIME PERIOD. FIRSTLY, SUNDAY
NIGHT INTO MONDAY WILL SEE A COLD FRONTAL PASSAGE WHICH WILL INCLUDE
POCKETS OF FRONTOGENESIS. SECONDLY, BY MONDAY WE ARE EXPECTED TO BE
UNDER THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET. THIS MAY
ENHANCE THE LIFT ACROSS THE AREA. ALSO, THE JET MAY PROVIDE WIND
SHEAR THAT COULD SUPPORT STRONG TO SEVERE STORMS CAPABLE OF HAIL
AND DAMAGING WINDS. GIVEN THE MOISTURE THERE IS THE POTENTIAL FOR
HEAVY RAINFALL AS WELL. CELL TRAINING AND OR ANY SEVERE STORM
COULD LEAD TO LOCALIZED FLASH FLOODING.
DESPITE THE SHORTWAVE EJECTING OUT OVER THE NORTHERN PLAINS THE
MODELS SHOW A TROUGH REMAINING IN PLACE ACROSS THE PACNW AS WELL AS
THE UPPER LEVEL JET OVERHEAD. THE HIGHLY ANAMOLOUS MOISTURE ALSO
PUSHES EAST, BUT THERE IS STILL SUFFICIENT MOISTURE LINGERING ACROSS
THE AREA. THE SHEAR AND MOISTURE MAY ONCE AGAIN COULD SUPPORT STRONG
STORMS. THE COVERAGE IS MORE UNCERTAIN WITH THE LACK OF FORCING, SO
THE CONVECTION MAY BE MORE TERRAIN DRIVEN. CONFIDENCE DECREASES MID
WEEK AS THE SECOND PACNW TROUGH EITHER SWINGS THROUGH OR BECOMES A
CUT OFF LOW TO OUR WEST.
LOOK FOR DAYTIME HIGHS TO COOL DOWN MONDAY AND BEYOND DUE TO THAT
AFOREMENTIONED FRONTAL PASSAGE AS WELL AS THE CLOUD COVER AND
POTENTIAL SHOWERS.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 522 PM MDT SAT SEP 12 2026
SOME SHOWERS ARE PASSING THROUGH THE REGION THIS EVENING, THOUGH
IMPACTS TO TERMINALS ARE EXPECTED TO BE MINIMAL, IF ANYTHING AT
ALL. AS SUCH, VFR CONDITIONS PERSIST THROUGH TOMORROW MORNING.
STORMS REDEVELOP AND BECOME MORE WIDESPREAD TOMORROW BEGINNING
AROUND 17 UTC. THE TERMINALS MOST LIKELY TO BE IMPACTED ARE GJT,
RIL, MTJ, TEX, AND GUC. BRIEF DROPS IN VISIBILITY TO MVFR CANNOT
BE RULED OUT, THOUGH TERMINALS ARE EXPECTED TO REMAIN ABOVE ILS
BREAKPOINTS. OTHERWISE, GUSTS OF 20-28 KTS ARE EXPECTED TO
DEVELOP TOMORROW AFTERNOON FOR MOST, IF NOT ALL TERMINALS.
GJT WATCHES/WARNINGS/ADVISORIES
CO...NONE.
UT...NONE.
DISCUSSION...BS
AVIATION...TGJT
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