309
FXUS65 KSLC 161208
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
608 AM MDT WED SEP 16 2026
KEY MESSAGES, ISSUED 1044 PM MDT TUE SEP 15 2026
- DEEP MOISTURE WILL CONTINUE TO BRING AN ELEVATED THREAT OF
FLOODING TO PORTIONS OF SOUTHERN AND EASTERN UTAH THROUGH AT
LEAST FRIDAY.
- A FLOOD WATCH FOR FLASH FLOODING HAS BEEN ISSUED FROM LATE
TONIGHT THROUGH THURSDAY MORNING FOR PORTIONS OF SOUTHERN AND
EASTERN UTAH INCLUDING ZION NATIONAL PARK, CAPITOL REEF NATIONAL
PARK, GLEN CANYON RECREATION AREA, THE GREATER GRAND STAIRCASE-
ESCALANTE NATIONAL MONUMENT AREA, AND THE LOWER PARIA INCLUDING
BUCKSKIN GULCH AND PARIA CANYON NORTH OF THE ARIZONA BORDER.
- A MARGINAL RISK FOR SEVERE THUNDERSTORMS (LEVEL 1/5) CONTINUES
FOR WEDNESDAY MORNING INTO WEDNESDAY AFTERNOON ACROSS PORTIONS
OF NORTHERN UTAH.
- A MARGINAL RISK FOR EXCESSIVE RAINFALL (LEVEL 1/4) CONTINUES
FOR THURSDAY AND FRIDAY ACROSS SOUTHERN AND EASTERN UTAH.
DISCUSSION, ISSUED 1044 PM MDT TUE SEP 15 2026
AN UPPER LEVEL LOW WILL CONTINUE TO SHIFT DOWN THE
PACIFIC COAST THROUGH LATER THURSDAY INTO FRIDAY AND THEN
GRADUALLY EJECT ACROSS THE GREAT BASIN THROUGH SATURDAY.
DIFFLUENT SOUTHWEST FLOW WILL REMAIN IN PLACE, WITH MODEST
MOISTURE TRANSPORT THROUGH AT LEAST LATER THURSDAY. EMBEDDED IN
THIS SOUTHWEST FLOW WILL BE A MULTITUDE OF WEAK SHORTWAVE
TROUGHS OR REMNANT MCVS. THIS, COMBINED WITH PWATS IN THE 96-99TH
PERCENTILE, AND BROAD ASCENT WILL SUPPORT PERIODS OF CONVECTION
WITH VERY HEAVY RAINFALL, ESPECIALLY THROUGH FRIDAY MORNING.
EARLIER THUNDERSTORMS, WITH OCCASIONAL EMBEDDED SUPERCELLS
PRODUCED RAINFALL RATES AS HIGH AS 0.50 INCHES IN 20 MINUTES,
CAUSING MULTIPLE FLASH FLOODS IN THE WAHWEAP, LOWER PARIA
DRAINAGES AS WELL AS VARIOUS SLOT CANYONS IN THE SAN RAFAEL SWELL
INCLUDING LITTLE WILDHORSE NORTH OF GOBLIN VALLEY STATE PARK.
CURRENT MODEL TRENDS INDICATE ANOTHER SUBTLE SHORTWAVE EJECTING
ACROSS NORTHERN ARIZONA/SOUTHERN NEVADA AND SOUTHWEST UTAH WILL
AID IN THE DEVELOPMENT OF CONVECTION OVERNIGHT THROUGH ABOUT 6 AM
THIS MORNING ACROSS LOWER WASHINGTON COUNTY, IRON COUNTY AND
WESTERN KANE AND GARFIELD COUNTIES. RAINFALL RATES IN EXCESS OF
0.25 INCHES AN HOUR WILL BE POSSIBLE WITH THIS CONVECTION, WITH
AROUND A 10% CHANCE OF RAINFALL RATES IN EXCESS OF 0.50 INCHES PER
HOUR. A FLOOD WATCH FOR FLASH FLOODING BEGINS AT MIDNIGHT TONIGHT
AND CONTINUES THROUGH THURSDAY MORNING FOR ZION NATIONAL PARK AND
POINTS EAST. NO CHANGES HAVE BEEN MADE TO THE GOING WATCH.
THE STORM PREDICTION CENTER HAS OUTLOOKED PORTIONS OF NORTHERN
UTAH FOR A MARGINAL RISK FOR SEVERE THUNDERSTORMS, PARTICULARLY
FOR WEDNESDAY MORNING INTO EARLY WEDNESDAY AFTERNOON. A FEW STRONG
THUNDERSTORMS WILL BE POSSIBLE ALONG THE PERIPHERY OF THE DEEPER
MOISTURE IN THIS AREA.
AFTERNOON CONVECTION WILL KICK OFF ACROSS THE REGION, WITH A
MULTITUDE OF CAMS SHOWING VERY WIDESPREAD HEAVY RAIN ACROSS MOST
OF SOUTHERN UTAH AFTER ABOUT 00Z. THIS MAY REQUIRE THE EXPANSION
OF THE FLOOD WATCH INTO LOWER WASHINGTON, IRON AND BEAVER COUNTIES
FOR LATE WEDNESDAY NIGHT INTO THURSDAY AFTERNOON. SOMETHING TO
MONITOR FOR FUTURE ADJUSTMENTS IF CAMS REMAIN CONSISTENT.
IT IS NOT RECOMMENDED TO HAVE PLANS INTO SLOT CANYONS, NORMALLY
DRY WASHES, AND OTHER AREAS PRONE TO FLASH FLOODING OVER THE NEXT
SEVERAL DAYS. NEARLY ALL NATIONAL PARK AND REC AREAS ARE CURRENTLY
AT PROBABLE FOR THE NEXT SEVERAL DAYS IN THE FLASH FLOOD POTENTIAL
PRODUCT.
AVIATION
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, ISSUED 344 AM MDT WED SEP 16 2026
MONSOON MOISTURE WILL REMAIN IN PLACE, PARTICULARLY
ACROSS SOUTHERN AND EASTERN UTAH, THROUGH THE NEXT SEVERAL DAYS.
FREQUENT LIGHTNING ALONG WITH GUSTY AND ERRATIC WINDS HAVE BEEN
OBSERVED WITH STORMS TODAY, AND THESE THREATS WILL CONTINUE WITH
ANY STRONGER STORMS THAT DEVELOP THROUGHOUT THE WEEK. SOUTHWEST
WINDS WILL REMAIN BREEZY 25-35 MPH ACROSS WESTERN UTAH, ALTHOUGH
MIN RH SHOULD REMAIN ABOVE 20% FOR MOST LOCATIONS.
SLC WATCHES/WARNINGS/ADVISORIES
UT...FLOOD WATCH FROM NOON MDT TODAY THROUGH LATE TONIGHT FOR UTZ121-
129.
FLOOD WATCH THROUGH LATE TONIGHT FOR UTZ124-128-130-131.
WY...NONE.
PUBLIC...
AVIATION...MAHAN
FIRE WEATHER...MAHAN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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