234
FXUS65 KGJT 300045
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
645 PM MDT SAT AUG 29 2026
KEY MESSAGES
- STRONG TO SEVERE THUNDERSTORMS REMAIN A THREAT THIS AFTERNOON
FOR NORTHEAST UT AND NORTHWEST CO, INCLUDING SMALL HAIL AND
STRONG WINDS.
- FLASH FLOODING REMAINS A THREAT TODAY THROUGH MONDAY AS
ORGANIZED AND TRAINING THUNDERSTORMS PRODUCE SATURATED SOIL
CONDITIONS AND EXCESSIVE RUNOFF.
- COOLER TEMPERATURES ARRIVE ACROSS THE REGION THIS WEEK.
- A DOWNTURN IN MOISTURE DEVELOPS TUESDAY, BUT CONCERN FOR
ADDITIONAL RAINFALL ASSOCIATED WITH EXTRA-TROPICAL MOISTURE
RETURNS WEDNESDAY.
DISCUSSION
ISSUED AT 1132 AM MDT SAT AUG 29 2026
A PLUME OF PACIFIC MOISTURE AHEAD OF A TROUGH SWINGING THROUGH
THE GREAT BASIN CONTINUES TO PRODUCE SCATTERED SHOWERS AND
THUNDERSTORMS. THUS FAR THIS MORNING, SHOWERS HAVE MANAGED TO
PRODUCE SOME GUSTS TO AROUND 40 MPH. STORM MOTIONS REMAIN SWIFT,
AND THUS THE FLASH FLOODING RISK REMAINS LOW. SUCCESSIVE STORMS
TRAINING ACROSS SENSITIVE TERRAIN THIS AFTERNOON AND THIS
EVENING COULD QUICKLY TURN ATTENTION TO FLASH FLOODING. STRONG
WINDS REMAIN A THREAT AS WELL, ALONG WITH SMALL HAIL, FAVORING
NORTHEAST UT AND NORTHWEST CO.
WITH A STRONG JET STREAK OVERHEAD SATURDAY NIGHT AND EARLY
SUNDAY, SHOWERS AND STORMS WILL LIKELY BE ABLE TO SUSTAIN
THEMSELVES. HIGH RESOLUTION MODELS ARE PREFERRING TO KEEP THIS
THREAT CONFINED ALONG THE CONTINENTAL DIVIDE AND ACROSS
NORTHEAST UT AND NORTHWEST CO. SHOWERS AND STORMS WILL TAPER
EARLY SUNDAY MORNING. CONVECTIVE DEBRIS AND CLOUD COVER WILL
LIKELY PROVIDE SOME INERTIA TO OVERCOME SUNDAY AS WE SEE ANOTHER
ROUND OF CONVECTION DEVELOP AHEAD OF ANOTHER PINCHED OFF TROUGH
OVER THE GREAT BASIN. AMPLE MOISTURE AWAITS, AS WPC EXPANDED
THEIR AREA OF 15 PERCENT RISK OF RAINFALL EXCEEDING FLASH FLOOD
GUIDANCE OVER THE ENTIRE CWA ON SUNDAY. STORM MOTIONS STILL LOOK
BRISK ON SUNDAY, BUT INCREASED TRAINING AND COVERAGE ARE LIKELY
TO ENHANCE THE FLASH FLOOD RISK, YET AGAIN. WETTER BOUNDARY
LAYERS ARE EXPECTED TO SUPPRESS SOME OF THE GUSTIER OUTFLOW
WINDS ON SUNDAY. HOWEVER, STORMS SHOULD STILL BE CAPABLE OF
PRODUCING SOME 35-45 MPH GUSTS, GIVEN THE STRONGER WINDS ALOFT.
THE OVERHEAD JET STREAK DOESN'T YIELD MUCH SUNDAY NIGHT AND
MODELS ARE EAGER TO KEEP SOME SHOWERS GOING INTO THE EARLY HOURS
OF MONDAY, LIKELY TAPERING AROUND DAYBREAK.
NEXT WEEK:
AS WE BEGIN NEXT WEEK, ENSEMBLES ARE SUPPORTING PWATS 160-180
PERCENT OF NORMAL THROUGH AT LEAST MONDAY, BEFORE A SLIGHT
DOWNTURN IN MOISTURE FOR TUESDAY. EXCESSIVE RAIN OUTLOOKS FROM
WPC HAVE HIGHLIGHTED A 25 PERCENT CHANCE FOR RAINFALL EXCEEDING
FLASH FLOOD GUIDANCE FOR MUCH OF EASTERN UT AND WESTERN CO ON
MONDAY. WHILE IT'S STILL TOO EARLY TO PINPOINT FLASH FLOOD
COVERAGE, FLOOD PRONE AREAS ACROSS THE REGION ARE HIGHLIGHTED IN
THIS HEAVY RAINFALL OUTLOOK. MODELS BEGIN TO DIVERGE IN
OUTCOMES BY WEDNESDAY LEADING TO RATHER LOW FORECAST CONFIDENCE
MIDWEEK AND BEYOND. THERE STILL REMAINS A SIGNAL FOR ANOTHER
PUSH OF MONSOONAL MOISTURE LATE NEXT WEEK. THIS MOISTURE COULD
ALSO BE ENHANCED BY A TROPICAL SYSTEM SITUATED IN THE EASTERN
PACIFIC, WHICH WE WILL HAVE TO SEE EVOLVE TO GAIN A CLEARER
PICTURE. AS FOR TEMPERATURES, A WELCOME RELIEF IS IN STORE AS
DAYTIME HIGHS ARE EXPECTED TO FALL BELOW NORMAL TO START NEXT
WEEK.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 600 PM MDT SAT AUG 29 2026
SCATTERED SHOWERS AND THUNDERSTORMS MOSTLY ALONG AND NORTH OF
THE I-70 CORRIDOR WILL DIMINISH TO SHOWERS THROUGH 06Z WITH
LIGHT SHOWERS LINGERING THROUGH 12Z. A BAND OF SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE MOVING INTO THE REGION
FROM THE SOUTHWEST TRACKING TO THE NORTHEAST. EXPECT THESE
STORMS TO TRACK ACROSS THE REGION SOUTH OF I-70 AND EAST OF THE
DIVIDE BY ABOUT 07Z. LOOK FOR WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS AFTER 17Z BECOMING MORE WIDESPREAD BETWEEN 20Z
AND 24Z. EXPECT MVFR TO IFR CONDITIONS BELOW ILS BREAKPOINTS AT
MOUNTAIN TAF SITES WITH ANY PASSING STORMS.
GJT WATCHES/WARNINGS/ADVISORIES
CO...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR COZ018.
UT...NONE.
DISCUSSION...TGJT
AVIATION...DB
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