306
FXUS65 KSLC 252119
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
319 PM MDT MON AUG 25 2025
SYNOPSIS
AN ONGOING MONSOON SURGE WILL BRING A HEIGHTENED
THREAT OF HEAVY RAIN WITH ANY THUNDERSTORMS ACROSS THE REGION
THROUGH TUESDAY. BY WEDNESDAY, DRIER AIR WILL BEGIN TO SHIFT
NORTHWARD INTO SOUTHERN UTAH, REACHING THE REMAINDER OF THE STATE
BY THURSDAY. DRIER CONDITIONS ARE EXPECTED TO CONTINUE FRIDAY INTO
THE WEEKEND.
SHORT TERM (THROUGH 12Z WEDNESDAY)
WIDESPREAD CONVECTION
CONTINUES TO DEVELOP IN ASSOCIATION WITH AN ONGOING MONSOON SURGE
IMPACTING MUCH OF THE REGION. A WEAK REMNANT MCV IS TRANSITIONING
THROUGH NORTHERN UTAH, SUPPORTING RELATIVELY STRONG CONVECTION
NEAR THE UTAH/IDAHO BORDER. ANOTHER, STRONG MCV SHIFTING ACROSS
SOUTHERN NEVADA IS PROVIDING ENHANCED LIFT TO PORTIONS OF
SOUTHWESTERN UTAH.
WITH PWATS AT OR ABOVE 1 INCH AND RELATIVELY SLOW STORM MOTIONS,
EXPECT ANY THUNDERSTORMS TO BE CAPABLE OF HEAVY RAINFALL, WITH
RAINFALL RATES IN EXCESS OF 0.50 TO 1.00" PER HOUR. THE STRONGEST
STORMS AND/OR THOSE THAT TRAIN OVER THE SAME AREAS MAY EXCEED
1.50" PER HOUR.
ANOTHER STRONG MCV WILL SHIFT ACROSS SOUTHERN UTAH TUESDAY
MORNING. TIMING ON THIS MCV VARIES ACROSS THE GUIDANCE, BUT THE
BULK OF THE CAMS SUPPORT AN ENHANCED THREAT OF FLASH FLOODING
ACROSS PORTIONS OF SOUTHERN UTAH IN ASSOCIATION WITH THIS MCV
AFTER 09Z THROUGH ABOUT 18Z. AS THIS DISTURBANCE MOVES NORTHWARD,
SUBSIDENCE MAY SUPPRESS CONVECTION ACROSS SOUTHERN UTAH,
PARTICULARLY SOUTHWESTERN UTAH DURING THE AFTERNOON. ALL IN ALL,
EXPECT ANOTHER BUSY DAY, STARTING EARLIER THAN NORMAL, FOR THE
CWA.
LONG TERM (AFTER 12Z WEDNESDAY), ISSUED 351 AM MDT
A GENERAL
SOUTHWESTERLY FLOW ALOFT ATOP LOW LEVEL WESTERLY FLOW WILL RESULT
IN A DRYING TREND ACROSS THE FORECAST AREA DURING THE MIDDLE TO
LATTER PORTION OF THE WEEK. HOW QUICKLY THE AIRMASS DRIES IS WHERE
THE GREATEST UNCERTAINTY LIES IN THE LONG TERM FORECAST, WITH
SOME GUIDANCE QUICKLY MIXING THIS MOISTURE OUT, PARTICULARLY
ACROSS SOUTHERN UTAH BY WEDNESDAY, WHILE OTHER GUIDANCE MAINTAINS
DEW POINTS IN THE UPPER 40S AND 50S STATEWIDE THROUGH WEDNESDAY
BEFORE GRADUALLY DRYING FROM SOUTH TO NORTH THURSDAY INTO FRIDAY.
IN THE ABSENCE OF AN EXCHANGE OF AIRMASSES SUCH AS WITH A STRONG
COLD FRONT, MORE OFTEN THAN NOT MOISTURE TENDS TO LINGER LONGER,
PARTICULARLY WITH A MOISTURE-RICH AIRMASS SUCH AS THE ONE WHICH
WILL BE IN PLACE AT THE BEGINNING OF THE LONG TERM PERIOD. AS SUCH
THE IDEA OF KEEPING POPS ELEVATED WEDNESDAY AFTERNOON ACROSS MOST
OF THE FORECAST AREA, FOLLOWED BY A GRADUAL DOWNWARD TREND
THURSDAY THROUGH FRIDAY SEEMS REASONABLE. IN FACT, WEDNESDAY COULD
END UP BEING AN ACTIVE FLASH FLOOD DAY ASSUMING LOW LEVEL
MOISTURE DOES IN FACT REMAIN, AS STORM MOTIONS WOULD TEND TO MOVE
CONVECTION INTO PRONE DRAINAGES INCLUDING CAPITOL REEF, THE SAN
RAFAEL SWELL, AS WELL AS THE GRAND STAIRCASE AND GLEN CANYON REC
AREAS.
THE AIRMASS WILL REMAIN RELATIVELY COOL THROUGH THE DURATION OF
THE WEEK DESPITE THE DECREASE IN CLOUD COVER. MAX TEMPS WILL RUN
5-8 DEGREES BELOW CLIMO THROUGH FRIDAY BEFORE GRADUALLY WARMING
HEADING INTO THE UPCOMING HOLIDAY WEEKEND.
AVIATION...KSLC
PREDOMINANT VFR CONDITIONS CAN BE EXPECTED AT
THE TERMINAL THROUGH THE TAF PERIOD, WITH NORTHWEST WINDS
SWITCHING TO DIURNAL SOUTHEAST AROUND 03Z. BRIEF VICINITY SHOWERS
MAY SPUR ERRATIC WINDS THROUGH EARLY EVENING, WITH 40% CHANCE OF A
THUNDERSTORM SPREADING OFF THE OQUIRRHS AND IMPACTING THE
TERMINAL DURING THE 22-02Z TIMEFRAME, WITH ANOTHER POTENTIAL ROUND
AFTER MIDNIGHT. THESE STORMS WOULD BE ACCOMPANIED BY GUSTY
OUTFLOW WINDS IN EXCESS OF 25 KTS AND LIGHTNING.
REST OF UTAH AND SOUTHWEST WYOMING
AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS MUCH OF THE REGION
TODAY, WHICH MAY IMPACT AREA TERMINALS WITH GUSTY OUTFLOW WINDS,
LIGHTNING, AND POTENTIALLY MVFR TO BRIEF IFR VISIBILITY WITHIN
HEAVIER RAINFALL. SOUTHERN TERMINALS MAY SEE CONTINUED CONVECTIVE
ACTIVITY WELL INTO LATE EVENING. AWAY FROM THESE STORMS, VFR
CONDITIONS WITH TERRAIN DRIVEN WINDS CAN BE EXPECTED.
FIRE WEATHER
AN ONGOING MONSOON SURGE WILL CONTINUE TO BRING
PERIODS OF THUNDERSTORMS WITH A HIGH POTENTIAL FOR WETTING RAINS
THROUGH TUESDAY. BY WEDNESDAY, DRIER AIR WILL BEGIN TO WORK INTO
SOUTHERN UTAH, REACHING THROUGH THE REMAINDER OF THE STATE BY
THURSDAY. THIS WILL BRING A DECREASE IN HUMIDITIES, THOUGH WITH
MAINLY TERRAIN DRIVEN WINDS, CRITICAL FIRE WEATHER CONDITIONS ARE
NOT EXPECTED.
EXPECT DRIER CONDITIONS OVER THE WEEKEND, WITH TERRAIN DRIVEN
WINDS AS HIGH PRESSURE BUILDS INTO THE REGION.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
KRUSE/SEAMAN/VERZELLA
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE
VISIT... HTTP://WEATHER.GOV/SALTLAKECITY
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