544
FXUS65 KSLC 071921
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
121 PM MDT WED OCT 7 2026
.KEY MESSAGES..
- A STRONG PACIFIC STORM SYSTEM WILL COMBINE WITH DEEP TROPICAL
MOISTURE FROM NOW HURRICANE RACHEL TO BRING THE THREAT OF
WIDESPREAD HEAVY RAIN TO MUCH OF UTAH AS EARLY AS LATE SATURDAY
THROUGH AT LEAST TUESDAY NIGHT.
- THE CURRENT TRACK FROM THE NATIONAL HURRICANE CENTER BRINGS THE
CENTER OF POST-TROPICAL DEPRESSION RACHEL TO THE UTAH-ARIZONA
BORDER NEAR ST. GEORGE BY 5 AM PST MONDAY, WITH THE CONE OF
UNCERTAINTY INCLUDING MUCH OF SOUTHERN UTAH. THE MAIN IMPACTS
FOR UTAH WILL BE VERY HEAVY RAINFALL.
- CURRENT GUIDANCE SUGGESTS MUCH OF UTAH WILL SEE BETWEEN 1 TO 2
INCHES OF RAIN, WITH LOCALLY HIGHER AMOUNTS IN EXCESS OF 3
INCHES ESPECIALLY ACROSS SOUTHERN UTAH. THIS AMOUNT OF RAIN WILL
INCREASE THE POTENTIAL FOR FLASH FLOODING IN PRONE AREAS SUCH
AS RECENT BURN SCARS AND SLOT CANYONS.
- THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL (LEVEL 2/4)
BETWEEN SUNDAY 12Z AND MONDAY 12Z, WITH THE REMAINDER OF UTAH IN
A MARGINAL RISK (LEVEL 1/4). THE EXCESSIVE RAINFALL OUTLOOKS ARE
ONLY ISSUED THROUGH DAY 5, SO EXPECT ADDITIONAL PERIODS OF
MARGINAL AND/OR SLIGHT RISK BEYOND 12Z MONDAY AS THE FORECAST
PROGRESSES THAT FAR.
DISCUSSION
UPPER LEVEL RIDGING WILL CONTINUE TO SHIFT INTO UTAH
THIS AFTERNOON. MEANWHILE HURRICANE RACHEL CONTINUES TO SHIFT
WEST ACROSS THE EASTERN PACIFIC WELL OFFSHORE SOUTHERN BAJA
CALIFORNIA. THE CURRENT NATIONAL HURRICANE CENTER TRACK BRINGS THE
CIRCULATION OF POST-TROPICAL DEPRESSION RACHEL NEAR ST. GEORGE BY
5 AM PST MONDAY, WITH THE CONE OF UNCERTAINTY FOR THIS TRACK OVER
MUCH OF SOUTHERN UTAH. NOTE THIS WOULD BE A POST-TROPICAL
DEPRESSION, NOT A TROPICAL STORM OR A HURRICANE. THUS, THE WIND
POTENTIAL IS MUCH MORE LIMITED.
FIRST, LET'S TALK ABOUT WHAT THIS MEANS FOR THE FORECAST. LOOKING
AT THE 00Z AND 12Z RUNS OF THE ENSEMBLE SUITE, CONFIDENCE IS HIGH
THAT TROPICAL MOISTURE FROM RACHEL WILL COMBINE WITH A PACIFIC
TROUGH CROSSING INTO THE WEST TO BRING A PERIOD OF MODERATE TO
HEAVY RAIN TO MUCH OF UTAH, BEGINNING AS EARLY AS SATURDAY
EVENING AND CONTINUING THROUGH AT LEAST TUESDAY MORNING AS THE
TROUGH SLOWLY CROSSES THE WEST. BETWEEN THE 07Z AND 13Z CYCLES OF
THE NBM, THE 25TH PERCENTILE OF PRECIPITATION INCREASED
SUBSTANTIALLY, SIGNALING THAT THE MAJORITY OF THE REMAINING "DRY"
ENSEMBLE MEMBERS ARE ALSO SHIFTING TO REPRESENT THE MAJORITY
SOLUTION.
THERE IS ALSO A SUBSET OF ENSEMBLE MEMBERS THAT INDICATE A SHALLOW
FRONT WILL COMBINE WITH POLAR AND SUB-TROPICAL JET COUPLING TO
BRING A PERIOD OF HEAVY RAIN TO MORE NORTHERN LOCATIONS, SOMEWHERE
BETWEEN SOUTHERN IDAHO AND NORTHERN UTAH SUNDAY NIGHT INTO MONDAY
MORNING. NOW, EVEN WITH MODELING ADVANCES IN 2026, THE LOCATION OF
A MESOSCALE BANDING FEATURE SUCH AS THIS WILL BE A LOW CONFIDENCE
FORECAST THIS FAR OUT, BUT IT IS SOMETHING THAT SHOULD BE
MONITORED.
RIGHT NOW, THE 25TH TO 75TH PERCENTILE FORECAST PRECIPITATION
RANGE WOULD BRING A GENERAL 1 TO 2 INCHES OF RAIN THROUGHOUT MUCH
OF UTAH AND UINTA COUNTY, WY BY TUESDAY MORNING. LOCALLY, SOME
LOCATIONS SUCH AS SOUTHWESTERN UTAH AND NORTHERN UTAH MAY SEE IN
EXCESS OF 3 INCHES. MORE ABOUT THE IMPACTS ON AREA RIVERS,
STREAMS, ETC WILL BE IN THE HYDROLOGY SECTION.
THERE IS MORE SPREAD ON HOW QUICKLY THIS UPPER LEVEL TROUGH EJECTS
INTO THE ROCKIES, WITH MOST OF THE GUIDANCE FAVORING A SLOWER
SYSTEM AND THUS MODERATE TO HEAVY RAIN CONTINUING BEYOND
TUESDAY...WITH A SUBSET OF THESE MEMBERS INGESTING ADDITIONAL
TROPICAL MOISTURE FROM TD TWENTY-E INTO EASTERN UTAH. WE WILL NEED
TO WATCH THIS, AS WELL, GIVEN THE AREA WILL LIKELY ALREADY BE
QUITE SATURATED FROM THE TROPICAL MOISTURE ASSOCIATED WITH RACHEL.
AVIATION
KSLC...THE SLC TERMINAL WILL SEE VFR CONDITIONS THROUGH THE EVENING
WITH SOME SCATTERED CLOUDS. NORTHWEST WINDS ARE EXPECTED TO SHIFT
BACK TO THE SOUTH BETWEEN 03Z AND 05Z.
REST OF UTAH AND SOUTHWEST WYOMING...THE AIRSPACE WILL SEE VFR
CONDITIONS THROUGH THE EVENING. CUMULUS CLOUDS WILL CONTINUE TO
DEVELOP OVER THE HIGHER TERRAIN THROUGH THE EVENING, WITH A FEW
SHOWERS AND THUNDERSTORMS. ANY STORMS THAT DEVELOP COULD PRODUCE
GUSTY AND ERRATIC THUNDERSTORM WINDS, LIGHTNING, AND BRIEF
MOUNTAIN OBSCURATIONS. AWAY FROM THUNDERSTORMS, WINDS WILL BE
LIGHT AND TERRAIN DRIVEN.
FIRE WEATHER
AFTER A DRY AND WARM PERIOD THROUGH THE END OF THE
WORKWEEK, A PACIFIC SYSTEM COMBINED WITH TROPICAL MOISTURE FROM
NOW HURRICANE RACHEL WILL BRING A PROLONGED PERIOD OF MODERATE TO
HEAVY RAIN TO MUCH OF UTAH. FOR LOCATIONS ABOVE ABOUT 10,000 FEET,
ACCUMULATING SNOW IS LIKELY MONDAY NIGHT INTO EARLY TUESDAY
MORNING, THOUGH AMOUNTS WILL BE LIGHT.
HYDROLOGY
WITH WIDESPREAD PRECIPITATION OF 1 TO 2 INCHES,
LOCALLY IN EXCESS OF 3 INCHES BETWEEN LATE SATURDAY AND TUESDAY
MORNING, EXPECT ALL AREA WATERWAYS INCLUDING STREAMS, RIVERS,
NORMALLY DRY WASHES, CREEKS, AND SLOT CANYONS TO HAVE RISING,
FAST FLOWS BY SUNDAY. CURRENT FORECASTS DO NOT BRING ANY RIVERS TO
FLOOD STAGE, BUT THIS WILL BE MONITORED AS THE FINE DETAILS OF
HEAVY RAIN BANDS BECOME MORE CONFIDENT. THOSE WITH INTERESTS NEAR
RIVERS, STREAMS, CREEKS AND RECENT BURN SCARS SHOULD CLOSELY
MONITOR THE FORECAST OVER THE NEXT SEVERAL DAYS. THOSE WITH
OUTDOOR PLANS SUNDAY ONWARD THAT INCLUDE ANY TRAVEL NEAR WATERWAYS
ACROSS UTAH SHOULD CONSIDER ALTERNATE PLANS.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
KRUSE/TRAPHAGAN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page