886
FXUS65 KGJT 301033
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
433 AM MDT SUN AUG 30 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.
UPDATE
ISSUED AT 427 AM MDT SUN AUG 30 2026
LATEST GUIDANCE CONTINUES TO SUGGEST ROUNDS OF SHOWERS AND
THUNDERSTORMS TODAY AND INTO THE EVENING HOURS ACROSS THE CWA.
WITH INCREASED MONSOONAL MOISTURE, HEAVY RAIN WILL BE A CONCERN
THROUGH THE DAY ALONG WITH GUSTY OUTFLOW WINDS AND SMALL
HAIL. RECENT BURN SCARS ARE ESPECIALLY SUSCEPTIBLE TO HEAVY
RAINFALL WHICH MAY CAUSE DEBRIS FLOWS AND FLASH FLOODING. DUE TO
THESE REASONS, WENT AHEAD AND ISSUED A FLOOD WATCH TO ACCOUNT
FOR THESE POSSIBILITIES.
DISCUSSION
ISSUED AT 1131 PM MDT SAT AUG 29 2026
MODELS ARE IN GOOD AGREEMENT WITH A TROUGH ALONG THE WEST COAST WITH
THE ASSOCIATED LOW TRACKING EAST ALONG THE WASHINGTON/BC BORDER AND
A BROAD HIGH PRESSURE OVER TEXAS PULLING DEEP MONSOONAL MOISTURE UP
THROUGH ARIZONA INTO EASTERN UTAH AND WESTERN COLORADO KEEPING PWATS
OVER AN INCH, AND KEEPING THE JET IN PLACE SOUTHWEST TO NORTHEAST
ACROSS THE WESTERN STATES. THOUGH MOST OF THE ENERGY ACROSS THE
NORTH WAS SPENT ON THE AFTERNOON THUNDERSTORMS, UPPER-LEVEL DYNAMICS
ARE KEEPING SHOWERS IN THE FORECAST WITH OCCASIONAL LIGHTNING
OVERNIGHT. THE MOISTURE STAYS IN THE AREA INTO TUESDAY BEFORE DRIER
AIR PUSHES IN FROM THE NORTHWEST.
THE JET IS DIPPING SOUTH ACROSS THE REGION TO SUPPORT THE CONVECTION
WE HAD SATURDAY ACROSS THE NORTHERN AREAS SPREADING SOUTH OF I-70 TO
THE SAN JUANS SUNDAY. A SHORTWAVE TROUGH DROPS DOWN SUNDAY AFTERNOON
INTO THE EVENING BRINGING A ROUND OF STRONGER THUNDERSTORMS WITH
NOCTURNAL STORMS INTO MONDAY. A SECOND SHORTWAVE IS THREATENING A
REPEAT MONDAY AFTERNOON AND EVENING, BUT MODELS ARE DIVERGING ON THE
TIMING, SO CONFIDENCE IS LOWER AT THIS POINT. STAY TUNED FOR
UPDATES. THE PRIMARY THREATS ARE FLASH FLOODING DUE TO HEAVY RAIN
AND TRAINING STORMS, ESPECIALLY NEAR RECENT FIRE SCARS, POSSIBLE
LARGE HAIL, AND 60 MPH OUTFLOW WINDS AS IS TYPICAL WITH SEVERE
THUNDERSTORMS. THOUGH THE AIR WILL BE SATURATED TO THE SURFACE,
EXPECT STRONG WINDS DUE TO THE WET DOWNBURSTS MIXING DOWN THE 40 MPH
FLOW AT H500.
MODELS FURTHER 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
REMAIN BELOW NORMAL THROUGH MID WEEK.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1156 PM MDT SAT AUG 29 2026
SHOWERS AND STORMS WILL CONTINUE OVERNIGHT, MAINLY NORTH OF THE
I-70 CORRIDOR. BROKEN TO OVERCAST SKIES WILL REMAIN IN PLACE
UNDER AND NEAR THIS CONVECTION OVERNIGHT BUT DO NOT ANTICIPATE
MVFR EXCEPT UNDERNEATH THE STRONGER CELLS. THIS AFTERNOON,
ANOTHER ROUND OF CONVECTION IS EXPECTED WITH MORE SHOWERS AND
STORMS EXPECTED FOR ALL TAF SITES. HEAVY RAIN, LIGHTNING, AND
GUSTY OUTFLOW WINDS WILL REMAIN THE BIGGEST CONCERNS FOR THIS
CONVECTION. ILS BREAKPOINTS WILL LIKELY BE MET FOR MOST TAF
SITES WITH MVFR/IFR UNDER AND NEAR THE STRONGEST CELLS AND
SHOWERS DUE TO LOW CIGS AND VIS. DESPITE THAT, VFR WILL REMAIN
PREDOMINANT.
GJT WATCHES/WARNINGS/ADVISORIES
CO...FLOOD WATCH THROUGH THIS EVENING FOR COZ002-003-006>014-
017>021.
UT...FLOOD WATCH THROUGH THIS EVENING FOR UTZ022-025-027>029.
UPDATE...TGR
DISCUSSION...DB/TGJT
AVIATION...TGJT
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