930
FXUS65 KSLC 080959
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
359 AM MDT THU OCT 8 2026
KEY MESSAGES, ISSUED 1008 PM MDT WED OCT 7 2026
- WIDESPREAD MODERATE TO HEAVY RAINFALL THREAT INCREASES LATE
SATURDAY THROUGH TUESDAY AS A REMNANT TROPICAL SYSTEM AND
ASSOCIATED DEEP MOISTURE LIFT THROUGH AND INTERACT WITH AN
APPROACHING TROUGH. WIDESPREAD WATER AMOUNTS OF 1 TO 2 INCHES
ARE FORECAST, WITH LOCALLY HIGHER AMOUNTS IN EXCESS OF 3 INCHES
POSSIBLE IN AREAS OF SOUTHERN UTAH AND HIGH TERRAIN.
- PER THE NATIONAL HURRICANE CENTER TRACK, HURRICANE RACHEL IS
FAVORED TO WEAKEN FOLLOWING LANDFALL, WITH THE POST-TROPICAL
STORM/DEPRESSION LIFTING THROUGH UTAH SUNDAY INTO MONDAY. THIS
PERIOD IS EXPECTED TO SEE THE HIGHEST THREAT OF HEAVY RAINFALL.
- BY SUNDAY, A SLIGHT RISK FOR EXCESSIVE RAINFALL (LEVEL 2/4) IS
NOTED OVER MUCH OF SOUTHERN UTAH, AND A MARGINAL RISK (LEVEL
1/4) ELSEWHERE. THERE IS POTENTIAL FOR FURTHER EXPANSION IN
SUBSEQUENT DAYS AS THE FORECAST WINDOW PROGRESSES FORWARD.
EXCESSIVE RAINFALL WILL BE MOST LIKELY OVER RAIN SENSITIVE
BASINS (BURN SCARS, SLOT CANYONS, TYPICALLY DRY WASHES, AND
SLICKROCK AREAS).
DISCUSSION, ISSUED 1008 PM MDT WED OCT 7 2026
ANOTHER MILD DAY ACROSS THE REGION TODAY AS RIDGING
REMAINS THE DOMINANT INFLUENCE. WHILE MOST AREAS REMAINED DRY,
SUFFICIENT MOISTURE BENEATH THE RIDGE DID SPARK SOME ISOLATED
AFTERNOON SHOWERS AND THUNDERSTORMS ACROSS UTAH'S HIGH TERRAIN,
BUT DRY CONDITIONS ARE OVERWHELMINGLY FAVORED OVERNIGHT INTO
THURSDAY. OTHERWISE, TEMPERATURES WERE ONCE AGAIN QUITE MILD WITH
AFTERNOON HIGHS AROUND 10 TO 15 DEGREES ABOVE NORMAL. THROUGH
FRIDAY, THERE IS MINIMAL SHIFT IN THE OVERALL FORECAST PATTERN,
AND AS SUCH THE DAY TO DAY WEATHER LOOKS TO BE VERY SIMILAR TO
THAT OF WEDNESDAY'S.
THE FORECAST WILL BEGIN TO CHANGE SUBSTANTIALLY SATURDAY ON INTO
EARLY NEXT WEEK. THE PRIMARY TWO FORECAST ELEMENTS IN PLAY ARE THE
REMNANTS OF NOW HURRICANE RACHEL APPROACHING FROM THE SOUTH, AND
A DEEPENING NORTHERN STREAM TROUGH DIGGING TOWARDS THE REGION
THROUGH THE PACNW. DEEP TROPICAL MOISTURE WILL START TO OVERSPREAD
THE REGION, WITH A CORRESPONDING INCREASE IN PRECIPITATION
CHANCES AS IT DOES SO. THE CHANCE FOR WIDESPREAD MODERATE TO HEAVY
RAINFALL THEN BECOMES MAXIMIZED IN THE SUNDAY TO MONDAY TIME
FRAME AS THE CORE OF RACHEL'S REMNANTS LIFT THROUGH AND INTERACT
WITH THE DEEPENING TROUGH. WHILE THERE IS STILL SOME UNCERTAINTY
IN RACHEL'S EXACT TRACK, MODELS HAVE HONED IN ENOUGH TO WHERE
THERE ARE VERY FEW ENSEMBLE MEMBERS ON THE DRIER SIDE OF SOLUTIONS
FOR UTAH AND SOUTHWEST WYOMING.
IN REGARDS TO THE PLACEMENT OF THE HIGHER RAINFALL TOTALS,
GUIDANCE STILL FAVORS PORTIONS OF SOUTH TO SOUTHWEST UTAH, AS WELL
AS MUCH OF UTAH'S HIGH TERRAIN. EVEN THEN, THE 25TH TO 75TH
PERCENTILE HAS MAINTAINED WIDESPREAD 1 TO 2 INCH RAINFALL AMOUNTS
ACROSS THE MAJORITY OF THE FORECAST REGION, INCLUDING AREAS
FURTHER NORTH. IF ANYTHING, RAINFALL AMOUNTS HAVE SLIGHTLY
INCREASED FROM THE PRIOR FORECAST. LOCALLY, THE FORECAST ALSO
CONTINUES TO SUPPORT HIGHER AMOUNTS IN EXCESS OF 3 INCHES IN
PORTIONS OF SOUTHWEST UTAH, AND HIGH TERRAIN IN NORTHERN UTAH.
WHILE UNCERTAIN, HOW EXACTLY THE TROUGH INTERACTS WITH RACHEL'S
REMNANTS MAY YIELD ANOTHER LOCAL MAXIMUM IN RAINFALL. THIS WOULD
OCCUR AS A FRONT FROM THE NORTHERN TROUGH SINKS INTO THE AREA, AND
THE NORTHERN JET THEN PHASES/COUPLES WITH THE SOUTHERN SUB-
TROPICAL JET AS DEEP TROPICAL MOISTURE CONTINUES TO LIFT THROUGH
OVERHEAD. SO FAR PLACEMENT FOR SUCH A FEATURE LEANS TOWARDS
SOMEWHERE IN NORTHERN UTAH, BUT WITH MULTIPLE MOVING PARTS SEVERAL
DAYS OUT, IT IS DIFFICULT TO PUT MUCH CONFIDENCE IN ANY
PARTICULAR MODEL RUN. THIS FEATURE WOULD ALSO LIKELY BE QUITE
NARROW IN WIDTH, MAKING PLACEMENT FURTHER DIFFICULT TO PIN DOWN.
ALL THE SAME, IT'LL BE SOMETHING TO KEEP AN EYE ON AS IT WOULD
BRING POTENTIAL FOR ANOTHER SWATH OF LOCALLY HIGHER RAINFALL
AMOUNTS WITH A MORE PROLONGED PERIOD OF MODERATE TO HEAVY RAIN. AS
FAR AS FLOODING IS CONCERNED, THE HIGHEST THREAT WILL BE OVER
THOSE TYPICAL RAIN SENSITIVE BASINS SUCH AS SLOT CANYONS,
TYPICALLY DRY WASHES, SLICKROCK AREAS, AND AREA BURN SCARS. THAT
SAID, EVEN MORE URBAN AREAS WHERE HEAVIER RAINFALL CAN OVERWHELM
DRAINAGE WILL BE SOMETHING TO MONITOR, ESPECIALLY AS AREA RIVERS
AND STREAMS WILL SEE RESPONSE FROM THE RAIN/RUNOFF (SEE HYDROLOGY
SECTION).
UNCERTAINTY IN THE FORECAST INCREASES QUITE A BIT TUESDAY AND
WEDNESDAY. MODELS GENERALLY SUPPORT THE LARGE TROUGH DEEPENING
INTO THE SOUTHWEST CONUS, SLOWING ITS MOVEMENT, AND CUTTING OFF TO
AN EXTENT. WHILE THIS OCCURS, PER THE NHC TRACK, TROPICAL STORM
SIMON (EXPECTED TO STRENGTHEN INTO A HURRICANE) IS FORECAST TO BE
MOVING NORTHWARD ALONG THE MEXICO COAST OR GULF OF CALIFORNIA.
MOISTURE WITH THIS TROPICAL SYSTEM MAY THEN ONCE AGAIN LIFT INTO
THE SLOWLY PROGRESSING TROUGH, THROUGH THE DESERT SOUTHWEST AND
INTO PORTIONS OF THE INTERMOUNTAIN WEST AND ROCKIES. THE EXACT
TRACK OF SIMON AS WELL AS THE EVOLUTION OF THE DEEP TROUGH WILL
DETERMINE IF OR HOW MUCH OF THE LOCAL AREA SEES ANY IMPACTS, OR IF
MOISTURE IS SHUNTED EASTWARD. MODELS CONTINUE TO HAVE QUITE A BIT
OF SPREAD IN THOSE DETAILS, BUT CERTAINLY WILL BE WORTH WATCHING
TRENDS GIVEN THE PRECEDING IMPACTS FROM RACHEL, AND LIKELIHOOD OF
WIDESPREAD SATURATED SOILS.
WHILE IN THE EXTENDED RANGE, THERE ARE SOME INTERESTING MODEL
SOLUTIONS TOWARDS THE END OF THE WORK WEEK, ALBEIT WITH HIGH
UNCERTAINTY AND MODEL SPREAD. AS HAS BEEN THE CASE, IT'LL LARGELY
DEPEND ON THE EVOLUTION OF THE LARGE SCALE TROUGH. IN THIS CASE,
IF THE CUTOFF TROUGH CAN PHASE WITH ANOTHER DEEPENING NORTHERN
STREAM TROUGH, OR IF IT'LL JUST TRANSLATE THROUGH OVERHEAD WITH
MINIMAL INTERACTION. IN THE PHASING SCENARIO (FAVORED MORE BY GEFS
MEMBERS), A STRONG COLD FRONT MOVES THROUGH FOLLOWED BY QUITE A
COLD AIRMASS. THE DETERMINISTIC GFS FOR EXAMPLE HAS 700 MB
TEMPERATURES ACROSS THE AREA FALLING TO AROUND -5C TO -9C. THE
CUTOFF SCENARIO (FAVORED MORE BY ECM ENS MEMBERS) WOULD HAVE
MINIMAL THERMAL ADVECTION WITH IT, AND MAINTAIN MORE SEASONABLE
TEMPERATURES. GIVEN THE COLDER SCENARIOS WOULD CARRY SOME THREAT
OF OVERNIGHT LOWS BELOW FREEZING TO PORTIONS OF NORTHERN UTAH,
ANOTHER AREA TO MONITOR TRENDS.
HYDROLOGY, ISSUED 1008 PM MDT WED OCT 7 2026
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.
AVIATION, ISSUED 1050 PM MDT WED OCT 7 2026
KSLC...VFR CONDITIONS WILL PREVAIL AT THE KSLC TERMINAL THROUGH THE
TAF PERIOD. LIGHT SOUTHERLY WINDS REMAIN IN PLACE BEFORE SWITCHING
TO DIURNALLY-DRIVEN NORTHWESTERLIES AROUND 17Z. THE SOUTHEASTERLIES
WILL RETURN AROUND 3Z.
REST OF UTAH AND SOUTHWEST WYOMING...VFR CONDITIONS WILL PREVAIL
ACROSS ALL REGIONAL TERMINALS, WITH GENERALLY LIGHT DIURNALLY-DRIVEN
WINDS THROUGH THE TAF PERIOD. CUMULUS CLOUDS WILL CONTINUE TO
DEVELOP OVER THE HIGHER TERRAIN THROUGH THE OVERNIGHT HOURS WITH
SOME ISOLATED SHOWERS AND THUNDERTORMS. THESE STORMS COULD BRING
SOME GUSTY AND ERRATIC WINDS, LIGHTNING, AND A BRIEF MOUNTAIN
OBSCURATIONS.
FIRE WEATHER
MILD CONDITIONS WITH LIGHT WINDS WILL CONTINUE
ACROSS THE AREA THROUGH FRIDAY, WHILE A SUBTLE WEATHER
DISTURBANCE WILL BRING ISOLATED TO WIDELY SCATTERED DIURNAL
SHOWERS AND THUNDERSTORMS. SOUTHERLY WINDS BEGIN TO INCREASE ON
FRIDAY AHEAD OF AN APPROACHING STORM SYSTEM. THESE WINDS WILL
CONTINUE TO INCREASE SATURDAY AND POTENTIALLY INTO SUNDAY.
LOCALIZED MARGINAL CRITICAL FIRE WEATHER CONDITIONS WILL BE
POSSIBLE FRIDAY AFTERNOON BEFORE HUMIDITIES INCREASE FOR THE
WEEKEND.
THE APPROACHING STORM SYSTEM WILL START TO BRING MORE SCATTERED
TO NUMEROUS SHOWERS AND THUNDERSTORMS TO THE AREA ON SATURDAY,
WITH SOME STORMS CAPABLE OF PRODUCING WETTING RAINS. SATURDAY
NIGHT THROUGH SUNDAY NIGHT, TROPICAL MOISTURE FROM HURRICANE
RACHEL WILL SPREAD INTO UTAH, LEADING TO WIDESPREAD MODERATE TO
HEAVY RAIN. PERIODS OF PRECIPITATION LOOK TO CONTINUE THROUGH AT
LEAST TUESDAY AND POTENTIALLY INTO WEDNESDAY AS THE STORM SYSTEM
SLOWLY MAKES ITS WAY INTO THE AREA. THERE IS SOME UNCERTAINTY AS
TO HOW MUCH ADDITIONAL PRECIPITATION WILL BE POSSIBLE, AS IT
DEPENDS ON IF MOISTURE FROM TROPICAL STORM SIMON REACHES UTAH ON
TUESDAY OR IF IT TRACKS EAST OF THE AREA. NEVERTHELESS, THERE IS A
GOOD CHANCE FOR PERIODS OF WETTING RAIN DURING THIS TIME. WITH
COOLER AIR SPREADING IN, THERE WILL BE A CHANCE FOR LIGHT
ACCUMULATING SNOW, MAINLY ABOVE 9000 FEET, PARTICULARLY TUESDAY
INTO WEDNESDAY.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
PUBLIC...WARTHEN
AVIATION...TEKOE
FIRE WEATHER...CHENG
HYDROLOGY...KRUSE
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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