571
FXUS65 KSLC 162031
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
231 PM MDT WED SEP 16 2026
KEY MESSAGES, ISSUED 1253 PM MDT WED SEP 16 2026
- FLASH FLOODING REMAINS THE PRIMARY WEATHER RISK ACROSS SOUTHERN
AND EASTERN UTAH THROUGH FRIDAY. MULTIPLE ROUNDS OF SHOWERS AND
THUNDERSTORMS WILL BRING THE THREAT FOR LOCALLY HEAVY RAINFALL.
- A FLOOD WATCH FOR FLASH FLOODING HAS BEEN ISSUED FROM LATE
TONIGHT THROUGH THURSDAY MORNING FOR MUCH OF SOUTHERN UTAH,
WHILE THE WATCH EXTENDS THROUGH THURSDAY EVENING FOR MUCH OF
CARBON AND EMERY COUNTIES.
- A MARGINAL RISK FOR SEVERE THUNDERSTORMS (LEVEL 1/5) CONTINUES
FOR WEDNESDAY MORNING INTO WEDNESDAY AFTERNOON ACROSS PORTIONS
OF NORTHERN UTAH.
DISCUSSION, ISSUED 1253 PM MDT WED SEP 16 2026
THE MAIN WEATHER THREAT WILL CONTINUE TO BE FLASH FLOODING,
ESPECIALLY ACROSS SOUTHERN AND EASTERN UTAH. A SLOW MOVING UPPER
LOW OVER NORTHERN CALIFORNIA NORTHWEST NEVADA WITH A BROAD RIDGE
TO OUR EAST IS HELPING TO DIRECT MONSOON MOISTURE NORTHWARD ACROSS
UTAH. WHILE ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS
WILL CONTINUE TO DEVELOP ACROSS MUCH OF THE AREA THIS AFTERNOON,
THE STRONGEST STORMS WITH THE BEST THREAT OF FLASH FLOODING WILL
BE ACROSS SOUTHERN AND EASTERN UTAH WHERE THE DEEPEST MOISTURE
AND CAPE VALUES TO AROUND 1000 J/KG WILL BE IN PLACE THIS
AFTERNOON. FORCING WILL CONTINUE INCREASE ACROSS SOUTHEASTERN UTAH
BY LATER THIS AFTERNOON INTO THIS EVENING AS A SHORTWAVE EMBEDDED
IN THE SOUTHERLY FLOW EVOLVES NORTHWARD OUT OF ARIZONA.
AS THIS WAVE PUSHES INTO EASTERN UTAH THIS EVENING, THE MOISTURE
AND FORCING WILL SPREAD IN FARTHER TO THE WEST INTO SOUTHWEST
UTAH AS WELL WITH THE DEEP SOUTHERLY MOISTURE FLOW FAVORING STORMS
DEVELOPING IN UPSLOPE PRONE AREAS FROM THE SOUTH, SUCH AS THE
PINE VALLEY MOUNTAINS (FORSYTH BURN SCAR), AS WELL AS ACROSS THE
GRAND STAIRCASE EAST TO BOULDER SUMMIT. IN ADDITION, THE
CONVERGENCE INTO THE TERRAIN AROUND CASTLE COUNTY, PRICE, AND
OVER THE TAVAPUTS WILL ALSO FAVOR CONTINUED THUNDERSTORM
DEVELOPMENT AND TRAINING. OF CONCERN IN SOUTHWEST UTAH, INCLUDING
THE PINE VALLEYS AND ST GEORGE AREA, IS THAT HEAVY RAINFALL WILL
TIMED OVERNIGHT, MAINLY BETWEEN 9 PM MDT AND THE EARLY MORNING
HOURS ON THURSDAY. MEANWHILE, ACROSS EASTERN UTAH OVERNIGHT, AS
THE MAIN SHORTWAVE MOVES THROUGH AN AREA OF BROAD LIGHT TO
MODERATE RAINFALL IS EXPECTED, WHICH WILL HELP TO FURTHER SATURATE
THE SOILS AND ADD WATER INTO AREA WATERWAYS. THIS MAY BECOME A
FACTOR INTO THURSDAY FOR MAINLY EMERY AND CARBON COUNTIES WHERE
THERE WILL BE THE HIGHEST POTENTIAL FOR THUNDERSTORMS DEVELOPING
LATER THURSDAY AFTERNOON THROUGH THURSDAY EVENING OFF OF THE
CENTRAL MOUNTAINS AND MOVING INTO AN ENVIRONMENT WITH 30-35 KNOTS
OF SHEAR AND 500-1000J/KG OF CAPE. TRAINING STRONGER
THUNDERSTORMS AND EVEN A SUPERCELL CANNOT BE RULED OUT THERE INTO
THURSDAY EVENING, AND WHEN COMBINED WITH ANY RAIN RECEIVED TODAY
AND TONIGHT, THIS MAY MORE EASILY POSE A FLOOD RISK.
THE POTENTIAL FOR FLASH FLOODING WILL CONTINUE ACROSS SOUTHERN AND
EASTERN UTAH THROUGH FRIDAY AS THE UPPER LEVEL LOW REMAINS TO OUR
WEST ALLOWING THE MONSOON MOISTURE TO REMAIN IN PLACE. FINALLY BY
SATURDAY, MODELS ARE IN GOOD AGREEMENT THAT THE THROUGH WILL
FINALLY PASS UTAH BRINING NORTHWESTERLY WINDS USHERING IN COOL
TEMPERATURES AND DRIER AIR. HOWEVER, THIS DRYING OUT TREND WILL BE
SHORT-LIVED AS ENSEMBLES ARE IN GOOD AGREEMENT THAT A CUTOFF LOW
WILL PARK NEAR LAS VEGAS, ALLOWING FOR A RETURN TO SOUTHERLY FLOW
ACROSS SOUTHERN UTAH WHICH WILL BRING MOISTURE BACK NORTHWARD
AGAIN ALLOWING FOR DAILY SHOWER AND THUNDERSTORMS CHANCES TO
RETURN AGAIN NEXT WEEK.
AVIATION, ISSUED 1253 PM MDT WED SEP 16 2026
KSLC...VFR CONDITIONS WILL PERSIST FOR THE KSLC TERMINAL THROUGH THE
PERIOD. A FEW LINGERING SHOWERS MOVING SOUTH OF THE TERMINAL THROUGH
~14Z WILL KEEP THE POTENTIAL FOR GUSTY AND ERRATIC WINDS, BUT
PRIMARILY GUSTY SOUTHERLIES PREVAIL. CONDITIONS WILL BE MOSTLY DRY
THROUGHOUT THE DAY WITH A FEW HIGHS. SHOWERS AND STORMS ARE POSSIBLE
(~25% CHANCE) AGAIN TONIGHT.
REST OF UTAH AND SOUTHWEST WYOMING...SHOWERS AND THUNDERSTORMS
CONTINUE THE FIRST FEW HOURS OF THE PERIOD, GENERALLY ENDING BETWEEN
12Z AND 15Z. GUSTY WINDS UP TO 30 KNOTS AND BRIEF MVFR CONDITIONS
ARE POSSIBLE. THERE WILL BE THE CHANCE OF SHOWERS AND THUNDERSTORMS
AGAIN WEDNESDAY AFTERNOON, BUT CHANCES GENERALLY REMAIN UNDER 30
PERCENT. AS BETTER MOISTURE MOVES INTO THE AREA STARTING AROUND 00Z,
SHOWER AND ISOLATED THUNDERSTORM CHANCES INCREASE FOR LATE IN THE
PERIOD. SOUTHERN TERMINALS SHOULD SEE PREVAILING RAIN AROUND 03Z.
MODELS HAVE SOME DISAGREEMENT ON TIMING FURTHER NORTH, SO HAVE
MOSTLY PROB30 FOR NOW, STARTING ABOUT 06Z.
FIRE WEATHER
MONSOON MOISTURE WILL REMAIN IN PLACE KEEPING HUMIDITY ELEVATED
THROUGH THE END OF THE WEEK. FLOOD WATCHES ARE IN PLACE ACROSS
MUCH OF SOUTHERN AND EASTERN UTAH DUE TO THE THREAT OF LOCALLY
HEAVY RAINFALL TODAY THROUGH THURSDAY. MOISTURE WILL LINGER INTO
FRIDAY, BUT DRIER AIR WILL START TO WORK IN FROM THE WEST, AGAIN
LIMITING THE BEST HEAVY RAIN THREAT TO EASTERN UTAH. OTHER THAN
THE HEAVY RAIN THREAT, ANY THUNDERSTORMS ARE CAPABLE OF PRODUCING
GUSTY AND ERRATIC WINDS, LIGHTNING, AND SMALL HAIL. BY SATURDAY
INTO SUNDAY, A COLD FRONT WILL CROSS THE STATE BRINING COOLER
TEMPERATURES AND DRIER CONDITIONS AGAIN. LOOKING FARTHER AHEAD,
ENSEMBLES ARE IN GOOD AGREEMENT ABOUT A CUTOFF LOW SETTLING IN
NEAR LAS VEGAS, WHICH WOULD HELP BRING MOISTURE NORTHWARD INTO
SOUTHERN UTAH AGAIN AS EARLY AS MONDAY, AND SUPPORTING SHOWER AND
THUNDERSTORM CHANCES AGAIN NEXT WEEK.
SLC WATCHES/WARNINGS/ADVISORIES
UT...FLOOD WATCH THROUGH THURSDAY EVENING FOR UTZ113-117-120-121.
FLOOD WATCH FROM 6 PM MDT THIS EVENING THROUGH LATE TONIGHT FOR
UTZ122-123-125>127.
FLOOD WATCH THROUGH LATE TONIGHT FOR UTZ124-128>131.
WY...NONE.
PUBLIC...CHURCH
AVIATION...VERZELLA
FIRE WEATHER...CHURCH
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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