261
FXUS65 KSLC 030401
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1001 PM MDT WED SEP 2 2026
KEY MESSAGES
- GUSTY SOUTHWEST WINDS ARE EXPECTED EACH AFTERNOON AND EVENING
ACROSS UTAH AND SOUTHWEST WYOMING THROUGH THE END OF THE WORK
WEEK. WITH MINIMUM RELATIVE HUMIDITIES APPROACHING CRITICAL
VALUES IN POCKETS OF WESTERN UTAH, THIS WILL RESULT IN SOME
LOCALLY CRITICAL FIRE WEATHER CONDITIONS.
- AN INFLUX OF TROPICAL MOISTURE OVER THE HOLIDAY WEEKEND WILL
INCREASE THE RISK OF FLASH FLOODING INTO EARLY NEXT WEEK,
PARTICULARLY ON SUNDAY ACROSS CENTRAL AND SOUTHERN UTAH.
DISCUSSION
UTAH AND SOUTHWEST WYOMING REMAIN SANDWICHED IN
BETWEEN AN UPPER LOW OFF THE PACIFIC NORTHWEST COAST AND A BROAD
RIDGE OVER THE CENTRAL UNITED STATES. THIS HAS RESULTED IN A
PERSISTENT BREEZY SOUTHWESTERLY FLOW THAT IS ADVECTING DRIER AIR
INTO THE AREA. THURSDAY IS ANTICIPATED TO BE THE DRIEST DAY FOR
THE REGION, WITH MINIMUM RELATIVE HUMIDITY VALUES APPROACHING
CRITICALLY LOW VALUES FOR PORTIONS OF WESTERN UTAH, THE NORTHWEST
DESERT IN PARTICULAR. THIS WILL LIKELY RESULT IN SOME LOCALLY
CRITICAL FIRE WEATHER CONDITIONS DURING THE AFTERNOON, BUT GIVEN
THE IMPROVEMENT IN FUELS FROM RECENT RAINS, THE FIRE DANGER IS NOT
AS HIGH AS IT COULD BE. THE AIRMASS OVER THE AREA WILL STAY JUST A
BIT ON THE COOL SIDE, WITH MAXES RUNNING NEAR TO UP TO 5F BELOW
SEASONAL NORMALS THROUGH THE END OF THE WORK WEEK.
AS WE ENTER THE HOLIDAY WEEKEND, ALL EYES WILL TURN TO THE EASTERN
PACIFIC WHERE HURRICANE MARIE IS CURRENTLY TRACKING WESTWARD AWAY
FROM MEXICO. GUIDANCE CONTINUES TO INDICATE THAT THE SOUTHERLY
FLOW WILL TAP INTO DEEP TROPICAL MOISTURE FROM THE SYSTEM,
BRINGING THAT MOISTURE UP THROUGH UTAH AND SOUTHWEST WYOMING BY
SUNDAY. THIS INFLUX OF MOISTURE WILL BRING THE RETURN OF FAIRLY
WIDESPREAD COVERAGE OF SHOWERS AND THUNDERSTORMS, WITH ANY STORMS
THAT DEVELOP CAPABLE OF PRODUCING HEAVY RAIN THAT COULD LEAD TO
FLASH FLOODING.
THERE REMAINS LOWER CONFIDENCE THAN USUAL IN THE TIMING OF THE
ARRIVAL OF THIS MOISTURE AND ITS TRAJECTORY, AS THIS IS DEPENDENT
ON THE PRECISE TRACK OF MARIE, SOMETHING THAT GLOBAL MODELS CAN
STRUGGLE WITH, AND ALSO THE TROUGH CURRENTLY OVER THE PACIFIC
NORTHWEST. THE PREVAILING THOUGHT IS THAT THE SYSTEM WILL SPIN
JUST OFF THE COAST THROUGH THE FIRST PART OF THE WEEKEND BEFORE
EVENTUALLY GRAZING NORTHERN UTAH EARLY NEXT WEEK. ITS PASSAGE IS
EXPECTED TO GIVE A MORE WESTERLY COMPONENT TO THE FLOW, CUTTING
OFF THE TROPICAL MOISTURE AND BRINGING DRIER AIR BACK IN. HOWEVER,
THERE REMAINS DISAGREEMENT AS TO WHEN IT WILL GRAZE THE AREA, AND
HOW FAR SOUTH THE SYSTEM WILL ACTUALLY GET. HOPEFULLY DETAILS WILL
BECOME A BIT CLEARER OVER THE NEXT FEW DAYS.
AVIATION, ISSUED 539 PM MDT WED SEP 2 2026
KSLC...NORTHWESTERLY WINDS ARE SLOWLY PUSHING CLOSER TO THE
TERMINAL, HOWEVER THERE IS A 40% CHANCE THAT WINDS REMAIN
SOUTHERLY AROUND 10-15KTS THROUGH THE EVENING AND OVERNIGHT HOURS.
IF WINDS DO SHIFT TO NORTHWESTERLY (~01-03Z), THEY ARE LIKELY TO
SHIFT BACK TO SOUTHERLY AFTER 05Z OR SO. VFR CONDITIONS WILL
PREVAIL.
REST OF UTAH AND SOUTHWEST WYOMING...SOUTHWESTERLY TO SOUTHERLY
WINDS WILL PERSIST THROUGH THE OVERNIGHT HOURS AT MOST SITES SOUTH
OF AND INCLUDING ROUGHLY KU19-KSVR-KEVW. NORTH OF THIS BOUNDARY,
SITES HAVE BEEN SLOWLY SHIFTING TO WESTERLY/NORTHWESTERLY, AND WILL
BECOME LARGELY LIGHT AND TERRAIN-DRIVEN OVERNIGHT. STRONG
SOUTHWESTERLY WINDS WILL RETURN AFTER 15-17Z THURSDAY ACROSS MUCH OF
THE AREA. VFR CONDITIONS WILL PREVAIL.
FIRE WEATHER
BREEZY SOUTHWEST FLOW WILL REMAIN OVER THE STATE
THROUGH THE END OF THE WORKWEEK, WITH ISOLATED GUSTS IN EXCESS OF
40 MPH DEVELOPING BOTH THURSDAY AND FRIDAY AFTERNOONS. DRIER AIR
CONTINUES TO ADVECT INTO THE STATE, WITH ISOLATED POCKETS OF
MINIMUM RHS NEAR CRITICAL VALUES DEVELOPING AGAIN BOTH THURSDAY
AND FRIDAY. THIS COMBINATION WILL BRING SOME LOCALLY CRITICAL
FIRE WEATHER CONDITIONS, BUT COVERAGE WILL NOT BE ENOUGH TO
WARRANT HEADLINES, ESPECIALLY CONSIDERING THE IMPROVED NATURE OF
FUELS. DEEP TROPICAL MOISTURE ASSOCIATED WITH HURRICANE MARIE WILL
SPREAD NORTHWARD ACROSS THE STATE OVER THE WEEKEND, PARTICULARLY
ON SUNDAY, BRINGING A HIGH CHANCE OF WETTING RAINFALL AND AN
INCREASED THREAT OF FLASH FLOODING, BEFORE DRIER CONDITIONS RETURN
BY THE MIDDLE OF NEXT WEEK.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...RED FLAG WARNING UNTIL 9 PM MDT THURSDAY FOR WYZ277.
PUBLIC...TRAPHAGAN
AVIATION...CUNNINGHAM
FIRE WEATHER...TRAPHAGAN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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