493
FXUS65 KSLC 212337
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
537 PM MDT WED OCT 21 2026
KEY MESSAGES, ISSUED 1229 PM MDT WED OCT 21 2026
- WIDESPREAD PRECIPITATION WILL BRING AN ELEVATED AND PROLONGED
THREAT OF FLASH FLOODING ACROSS SOUTHERN AND CENTRAL UTAH
THROUGH THURSDAY. THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL
(LEVEL 2 OF 4) ACROSS SOUTHERN UTAH TODAY, AND ACROSS SOUTHERN
THROUGH EAST CENTRAL UTAH THURSDAY.
- THERE IS A SLIGHT RISK (LEVEL 2 OF 5) FOR SEVERE THUNDERSTORMS
CAPABLE OF PRODUCING STRONG WINDS AND HAIL ACROSS SOUTHERN UTAH
WEDNESDAY AFTERNOON AND EVENING, AND A 2% CHANCE OF A TORNADO. A
MARGINAL RISK (LEVEL 1 OF 5) FOR SEVERE THUNDERSTORMS IS IN
PLACE ON WEDNESDAY ACROSS SOUTHERN AND WESTERN UTAH ON THURSDAY.
- THE LATE WEEK STORM WILL ALSO BRING ACCUMULATING SNOWFALL TO THE
HIGH TERRAIN ACROSS NORTHERN AND CENTRAL UTAH ON FRIDAY, WITH
1-4" LIKELY ABOVE 9000 FEET. LOCALLY HIGHER AMOUNTS ARE
POSSIBLE IN FAVORED LOCATIONS.
DISCUSSION, ISSUED 1015 PM MDT TUE OCT 20 2026
MIDDAY SATELLITE IMAGERY AND OBJECTIVE ANALYSIS SHOW AN UPPER LOW
SPINNING OFF THE CA COAST, WITH A DEEP LAYER OF SOUTHERLY FLOW
EXTENDING DOWNSTREAM ACROSS MUCH OF AZ AND SOUTHERN UT. THIS FLOW
HAS PULLED TROPICAL MOISTURE NORTHWARD INTO THE REGION, WHICH WILL
ENHANCE THE THREAT FOR HEAVY RAIN AND FLASH FLOODING ACROSS
SOUTHERN AND CENTRAL UTAH OVER THE NEXT 36 HOURS. AN EMBEDDED
UPPER JET LIFTING THROUGH WESTERN AZ IS AIDING LARGE SCALE ASCENT,
AND HAS RESULTED IN NUMEROUS STRONG TO SEVERE THUNDERSTORMS
ACROSS AZ OVER THE PAST FEW HOURS, WHILE PRECIPITATION HAS
REMAINED MORE STRATIFORM EXTENDING INTO SOUTH CENTRAL AND
SOUTHEAST UTAH.
AS THE UPSTREAM LOW ENCROACHES ON THE CA COAST THIS AFTERNOON
THROUGH TONIGHT, INCREASING UPPER LEVEL DIFFLUENCE WILL SPREAD
ACROSS SOUTHERN AND CENTRAL UTAH, RESULTING IN AN INCREASE IN
SHOWERS AND THUNDERSTORMS. WITH THE INCREASE IN HEAVY RAINFALL
FLOODING IS EXPECTED WITHIN MOST DRAINAGES ACROSS SOUTH CENTRAL
UTAH LATER THIS AFTERNOON THROUGH TONIGHT. ADDITIONALLY, AMPLE
DEEP LAYER SHEAR IN EXCESS OF 40 KTS WILL SUPPORT SUPERCELLS
CAPABLE OF ALL SEVERE WEATHER HAZARDS THIS AFTERNOON AND EVENING
ACROSS SOUTHERN UTAH WHERE SUFFICIENT INSTABILITY EXISTS. IT
APPEARS THE MOST LIKELY AREA FOR SEVERE CONVECTION WILL ENCOMPASS
FAR SOUTH CENTRAL AND SOUTHWEST UTAH WHERE BREAKS IN CLOUD COVER
ARE ALLOWING SURFACE HEATING AND DESTABILIZATION OF THE AIRMASS.
AS THE UPPER LOW SPREADS INLAND AND ACROSS THE WESTERN GREAT
BASIN THURSDAY, INCREASING LARGE SCALE FORCING WILL MAINTAIN
SHOWERS AND THUNDERSTORMS ACROSS SOUTHERN AND CENTRAL UTAH, WITH
THIS ACTIVITY SPREADING INTO NORTHERN UTAH DURING THE AFTERNOON
AND EVENING HOURS. AMPLE DEEP LAYER SHEAR WILL CONTINUE TO SUPPORT
ORGANIZED CONVECTION ANYWHERE SUFFICIENT INSTABILITY CAN DEVELOP
THROUGH THURSDAY EVENING, PARTICULARLY ACROSS SOUTHERN AND WESTERN
UTAH.
AS THE UPPER LOW QUICKLY LIFTS THROUGH NORTHERN UTAH INTO SOUTHERN
IDAHO THURSDAY NIGHT INTO FRIDAY, PRECIPITATION WILL WIND DOWN
FROM SOUTH TO NORTH WITH TIME. COLDER AIR BEING PULLED INTO THE
AREA AS THIS LOW PASSES WILL DROP SNOW LEVELS INTO THE 8000-8500
FOOT RANGE ACROSS NORTHERN UTAH. ACCUMULATING SNOW IS STILL
EXPECTED ACROSS THE NORTHERN MOUNTAINS ABOVE 9000 FEET, HOWEVER
THE OVERALL EVOLUTION OF THE PATTERN AND SHORTER DURATION OF
PRECIPITATION WILL LIKELY KEEP ACCUMULATION LIMITED TO THE 1-4"
RANGE, WITH A FEW POCKETS OF HIGHER AMOUNTS POSSIBLE.
IN THE WAKE OF THIS INITIAL LOW, A SECONDARY WAVE IS FORECAST TO
DIG INTO ARIZONA SATURDAY, BEFORE LIFTING INTO THE CENTRAL ROCKIES
ON SUNDAY. THIS WILL MAINTAIN COOL TEMPERATURES THROUGH THE
WEEKEND, WITH PRECIPITATION PERSISTING ACROSS EASTERN PORTIONS OF
THE FORECAST AREA. BEYOND THE WEEKEND, DRIER CONDITIONS WITH
SEASONAL TEMPERATURES ARE EXPECTED, HOWEVER CONFIDENCE IS LOW IN
HOW THE LARGE SCALE PATTERN WILL EVOLVE THROUGH NEXT WEEK.
AVIATION
KSLC...THE SLC TERMINAL WILL SEE VFR CONDITIONS THROUGH THE
OVERNIGHT HOURS WITH SHOWERS DIMINISHING EARLY THIS EVENING.
SOUTHERLY WINDS WILL CONTINUE OVERNIGHT AND THROUGH THE DAY
TOMORROW. SHOWERS AND STORMS WILL DEVELOP AGAIN TOMORROW, WITH A 30
PERCENT CHANCE OF IMPACTS TO THE TERMINAL IN THE AFTERNOON, GUSTY
WINDS BEING THE MAIN THREAT.
REST OF UTAH AND SOUTHWEST WYOMING...VFR CONDITIONS ARE EXPECTED TO
PREVAIL ACROSS THE AIRSPACE THROUGH THE OVERNIGHT HOURS. LINGERING
SHOWERS ARE EXPECTED TO DIMINISH OVER NORTHERN PORTIONS OF THE
AIRSPACE BY 02-03Z, WITH SHOWERS CONTINUING OVERNIGHT AND INTO
TOMORROW MORNING OVER SOUTHERN UTAH, WITH THE FOCUS OVERNIGHT
SHIFTING TO SOUTHEAST UTAH. SHOWERS AND STORMS WILL INCREASE IN
COVERAGE TOMORROW, SPREADING NORTHWARD DURING THE AFTERNOON THROUGH
TOMORROW EVENING. ANY STORMS THAT DEVELOP WILL BE CAPABLE OF
PRODUCING GUSTY AND ERRATIC WINDS, LIGHTNING, AND BRIEF MVFR
CONDITIONS.
SLC WATCHES/WARNINGS/ADVISORIES
UT...FLOOD WATCH THROUGH THURSDAY EVENING FOR UTZ117-120-121-123>131.
WY...NONE.
PUBLIC...SEAMAN
AVIATION...TRAPHAGAN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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