984
FXUS65 KSLC 100819
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
218 AM MDT SAT OCT 10 2026
KEY MESSAGES, ISSUED 1027 PM MDT FRI OCT 9 2026
- WIDESPREAD HEAVY RAINFALL IS EXPECTED TO OCCUR ACROSS THE
ENTIRETY OF THE FORECAST AREA STARTING SATURDAY
AFTERNOON/EVENING AS TROPICAL STORM RACHEL TRANSITIONS TO AN
EXTRATROPICAL SYSTEM TO OUR SOUTHWEST AND INTERACTS WITH A
STRONG MIDLEVEL TROUGH. WIDESPREAD RAINFALL AMOUNTS FROM 1-3"
ARE EXPECTED ACROSS MUCH OF THE FORECAST AREA, WITH LOCALIZED
AMOUNTS POTENTIALLY REACHING 4+" ACROSS LOCATIONS SUCH AS HIGHER
TERRAIN LOCATIONS ACROSS SOUTHWEST UTAH, THE BOOK CLIFFS, AND
LOCATIONS WITHIN AND ADJACENT TO THE BEAR RIVER RANGE.
- A WIND THREAT IS EXPECTED TO ACCOMPANY THIS SYSTEM AS IT BEGINS
TO TAKE ON EXTRATROPICAL CHARACTERISTICS. INITIALLY, ADVISORY
LEVEL WINDS WILL BEGIN TO DEVELOP ACROSS MOST UTAH VALLEY
LOCATIONS STARTING JUST AFTER MIDNIGHT TONIGHT, BECOMING MORE
WIDESPREAD SATURDAY AFTERNOON. ADVISORY LEVEL WINDS ARE FORECAST
TO REMAIN IN PLACE THROUGH AT LEAST MONDAY AFTERNOON.
- A MORE NOTABLE HIGH WIND THREAT LOOKS TO DEVELOP ACROSS THE
VALLEYS AND HIGH TERRAIN OF SOUTHWEST UTAH AS THE POTENTIAL
DEVELOPMENT OF A STING JET LOOKS TO OCCUR SUNDAY. THIS WOULD
BRING WIDESPREAD LOWER ELEVATION WINDS IN EXCESS OF 40 MPH WITH
HIGH TERRAIN AND RIDGELINES SEEING GUSTS POTENTIALLY EXCEED 70
MPH.
- THE POTENTIAL FOR SEVERE WEATHER EXISTS ACROSS SOUTHERN AND
EASTERN UTAH SUNDAY INTO MONDAY MORNING. THE PRIMARY THREAT WILL
BE SEVERE THUNDERSTORM GUSTS AND POSSIBLY ISOLATED TORNADOES.
DISCUSSION, ISSUED 1027 PM MDT FRI OCT 9 2026
EVENING SYNOPTIC ANALYSIS SHOWS WESTERLY FLOW STARTING
TO SHIFT MORE SOUTHWESTERLY AS A LARGE SCALE TROUGH CONTINUES TO
DEEPEN THROUGH THE PACNW. COMBINATION OF MODEST ENERGY ADVECTION
AND AVAILABLE MOISTURE RESULTED IN THE DEVELOPMENT OF WIDELY
SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EVENING, AND MODELS SUPPORT SOME ACTIVITY PERSISTING OVERNIGHT
INTO SATURDAY. MOISTURE SO FAR IS LARGELY IN THE MID LEVELS,
RESULTING IN MODESTLY HIGH CLOUD BASES. GIVEN THAT IN ADDITION TO
INCREASING SOUTHWESTERLY FLOW, MAY SEE ACTIVITY RESULT IN SOME
GUSTY AND ERRATIC WINDS AT TIMES.
THROUGH SATURDAY THE TROUGH WILL CONTINUE TO DEEPEN, AND TROPICAL
STORM RACHEL WILL BEGIN TO APPROACH THE COAST LIKELY SOMEWHERE
FROM SOUTHERN CALIFORNIA TO THE NORTHERN BAJA PENINSULA. DEEPER
TROPICAL MOISTURE ASSOCIATED WITH RACHEL WILL START TO BE PULLED
INTO THE TROUGH AND INTO THE INTERMOUNTAIN WEST. WITH THE
DEEPENING SOUTHWESTERLY FLOW, WIDESPREAD WIND GUSTS OF 30-45 MPH
OR SO WILL DEVELOP, WITH SOME GUSTS IN EXCESS OF 45 MPH IN
PORTIONS OF WESTERN UTAH AND CENTRAL TO NORTHERN LOW ELEVATION
VALLEYS. THESE AREAS HAVE A WIND ADVISORY IN EFFECT ACCORDINGLY.
OTHERWISE, WILL JUST SEE SCATTERED SHOWER AND THUNDERSTORM
ACTIVITY INCREASE THROUGH THE DAY. AN ISOLATED STRONG TO SEVERE
STORM WITH GUSTY WINDS MAY ALSO BE POSSIBLE GIVEN INCREASING SHEAR
LEADING TO POTENTIAL FOR BETTER STORM ORGANIZATION.
AS THE TROUGH DEEPENS SATURDAY INTO SATURDAY NIGHT, A WEAK
FRONTAL BOUNDARY WILL ALSO ADVANCE SLOWLY INTO NORTHERN UTAH. THE
COMBINATION OF GENERAL SYNOPTIC SUPPORT FOR ASCENT, THE FRONTAL
BOUNDARY, AND INCREASING MOISTURE WILL YIELD A FURTHER INCREASE IN
PRECIPITATION. WHILE PRECIPITATION WILL INCREASE AREAWIDE AS
RACHEL CONTINUES TO LIFT TOWARDS THE REGION, WHERE THIS FRONTAL
BOUNDARY IS SITUATED MAY SEE LOCALIZED ENHANCEMENT AND PERIODS OF
HEAVIER RAINFALL. AS MENTIONED IN PREVIOUS DISCUSSIONS, THIS
POTENTIAL WOULD SERVE AS A PREDECESSOR RAINFALL EVENT (PRE) WHICH
WOULD HELP SATURATE SOILS AHEAD OF THE MORE ANTICIPATED RAIN
INCOMING. IN ANY CASE, SOILS AREAWIDE WILL BEGIN TO SATURATE AS
RAIN INCREASES.
SUNDAY WILL SEE A WEAKENING AND DECAYING RACHEL LIFT THROUGH THE
GREAT BASIN AND INTO THE LARGE TROUGH, BRINGING A POTENTIAL FOR A
MULTIFACETED WEATHER HAZARD DAY. THESE THREATS INCLUDE FURTHER
HEAVY RAINFALL AND FLOODING, AREAS OF VERY GUSTY WINDS, AND SEVERE
WEATHER INCLUDING POSSIBLE TORNADOES. SOME OF THESE THREATS WILL
ON INTO AT LEAST EARLY MONDAY FOR PORTIONS OF THE AREA.
STARTING WITH RAINFALL, THE FORECAST HAS NOT CHANGED
SIGNIFICANTLY. OVERALL, A FAIRLY WIDESPREAD 1-3" IS EXPECTED.
LOCALLY HIGHER AMOUNTS, POSSIBLY ON THE ORDER OF 4+" WILL BE
POSSIBLE IN HIGH TERRAIN OF SOUTHWEST UTAH, AS WELL AS OTHER
FAVORED SOUTHERLY ASPECTS OF TERRAIN AROUND UTAH WHERE AN UPSLOPE
COMPONENT CAN ENHANCE RAINFALL. ADDITIONALLY, SOME HIGH RESOLUTION
CAMS SHOW SOME SIGNAL FOR FEEDER TYPE BANDS WRAPPING TOWARDS
RACHEL'S CIRCULATION, TRAINING OR MOVING VERY SLOWLY. SUCH
MESOSCALE FEATURES WILL BE DIFFICULT TO PIN DOWN IN ADVANCE, BUT
WOULD SERVE AS ANOTHER AREA THAT WOULD SEE POTENTIAL FOR HIGHER
RAINFALL AMOUNTS. THE HIGHEST FLASH FLOODING THREAT IS NOTED
ACROSS TYPICALLY RAIN SENSITIVE BASINS SUCH AS SLOT CANYONS,
TYPICALLY DRY WASHES, SLICKROCK AREAS, AND RECENT BURN SCARS. THAT
SAID, THE WIDESPREAD AND AT TIMES PROLONGED NATURE OF THE RAIN
WILL ALSO RESULT IN A GENERAL FLOOD THREAT, SUCH AS POTENTIAL FOR
URBAN FLOODING OR FLOODING OF POOR DRAINAGE AREAS AND PONDING OF
WATER ON ROADWAYS. ADDITIONALLY, AREA RIVERS AND CREEKS WILL SEE
RISES, AMOUNT DEPENDENT ON WHERE EXACTLY THE HEAVIEST RAINFALL
OCCURS.
STRONG WIND GUSTS WILL ALSO BE A CONTINUED THREAT SUNDAY INTO
SUNDAY NIGHT. AS IS TYPICAL WITH TROPICAL CYCLONES TRANSITIONING
TO EXTRATROPICAL, THE LOW LEVEL WIND FIELD WILL EXPAND, WITH 700
MB WINDS ALONG AND EAST OF THE REMNANT CIRCULATION FORECAST 40-70
KTS ROUGHLY. ANY MOMENTUM TRANSFER TO THE SURFACE WILL BRING
POTENTIAL FOR GUSTS AROUND 40-60 MPH IN TURN, WITH LOCALLY HIGHER
NUMBERS POSSIBLE WITH ANY SPOTS THAT CAN SEE SOME DOWNSLOPING
ENHANCEMENT. ADDITIONALLY, WITH THE STRONG 700 MB FLOW, HIGHER
ELEVATION RIDGETOPS WILL SEE MORE PERSISTENT GUSTS IN EXCESS OF 50
MPH, AND LIKELY SOME IN EXCESS OF 70 MPH (ESPECIALLY NEAR HIGHER
PEAKS). WITH MANY LOCATIONS LIKELY HAVING SATURATED SOILS, AND
MOST AREA TREES STILL REMAINING NEAR FULLY LEAFED AT THIS POINT IN
AUTUMN, THESE WINDS GUSTS MAY PROVE PARTICULARLY DAMAGING IN SOME
LOCATIONS. FOR NOW, WILL HOLD AT LEAST ANOTHER MODEL CYCLE BEFORE
OPTING WHETHER OR NOT TO SHIFT THE HIGH WIND WATCH TO A HIGH WIND
WARNING TO SEE IF THERE ARE ANY NOTABLE TRENDS IN GUIDANCE.
A SEVERE WEATHER THREAT IS ALSO NOTED, PARTICULARLY FOR PORTIONS
OF SOUTHERN TO EASTERN UTAH. REFS SHOWS WIDESPREAD MEAN SURFACE
INSTABILITY IN EXCESS OF 100 J/KG, WITH AROUND 400-800 J/KG ACROSS
POTIONS OF SOUTHERN TO EASTERN UTAH. ENSEMBLE MAX (ALSO SUPPORTED
BY SOME OTHER INDIVIDUAL CAMS) CONTINUES TO SHOW POTENTIAL FOR
POCKETS OF 1000-1500 J/KG, MOST LIKELY REALIZED IF SOME MODEST
BREAKS IN CLOUD COVER CAN FORM. WITH THE STRONG LOW TO MID LEVEL
FLOW, MODELS ALSO SUPPORT AROUND 40-60 KTS OF DEEP LAYER SHEAR AND
100-200 M2/S2 OF STORM RELATIVE HELICITY. IN TURN, ELONGATED
CURVED HODOGRAPHS CONTINUE TO BE NOTED IN MODEL FORECAST VERTICAL
PROFILES, WHICH WOULD SUPPORT AT LEAST SOME CONDITIONAL TORNADO
THREAT, ESPECIALLY IN ANY ACTIVITY THAT CAN REMAIN DISCRETE TO
SEMI-DISCRETE IN NATURE. OTHERWISE, ANY STORM ORGANIZATION WILL
BE LIKELY TO FURTHER HELP BRING THE STRONG MOMENTUM TO THE SURFACE
RESULTING IN SOME SEVERE LEVEL WIND GUSTS. THE WIND GUST THREAT
WOULD BE FURTHER ENHANCED IF ANY DRIER AIR CAN START TO WRAP INTO
THE REGION AND ENHANCE DCAPE VALUES.
RACHEL'S REMNANTS WILL CONTINUE TO EJECT AWAY FROM THE AREA
THROUGH MONDAY, BUT THE BROADER TROUGH WILL CUT OFF IN THE GREAT
BASIN AND SLOWLY WORK EAST THROUGH MIDWEEK. SUFFICIENT MOISTURE
WILL LINGER WITHIN THIS CUTOFF TO YIELD CONTINUED ELEVATED
PRECIPITATION CHANCES, AND THERE WILL BE SOME POTENTIAL FOR
PERIODS OF MODERATE TO HEAVY RAINFALL AS SYNOPTIC FORCING OVERHEAD
REMAINS RELATIVELY STRONG WITH THE TROUGH. GIVEN THE PRECEDING
RAIN FROM RACHEL'S PASSAGE AND SATURATED SOILS, ANY FURTHER
RAINFALL WILL CARRY SOME THREAT OF BEING EXCESSIVE IN SOME
LOCATIONS. SNOW LEVELS WILL GENERALLY RUN AROUND 8500-9500 FT,
ALLOWING SOME MOUNTAIN SNOW AT HIGHER ELEVATIONS AS WELL. WHILE
SOME MODEST ACCUMULATIONS ARE POSSIBLE, WARM ANTECEDENT CONDITIONS
AND LIKELY POOR LIQUID TO SNOW RATIOS FAR BELOW THE "STANDARD"
10:1 WILL LARGELY LIMIT MORE IMPACTFUL AMOUNTS. A MODEST COLD
FRONT WILL ALSO ACCOMPANY THE TROUGH AS IT SHIFTS THROUGH,
RESULTING IN A MARKED COOLDOWN TUESDAY WITH FORECAST HIGHS 10-15
DEGREES BELOW NORMAL. TEMPERATURES ARE THEN EXPECTED TO GRADUALLY
MODERATE BACK UPWARDS THROUGH THE WEEK, WITH DRIER WEATHER FAVORED
TO RETURN BY THURSDAY.
AVIATION, ISSUED 1048 PM MDT FRI OCT 9 2026
KSLC...VFR CONDITIONS WILL PERSIST FOR THE KSLC TERMINAL THROUGH THE
PERIOD WITH SOUTHERLY FLOW. A LOW-LEVEL WIND SHEAR OF 20-25 KTS MAY
DEVELOP ACROSS NORTHERN UTAH TONIGHT INTO THE EARLY SATURDAY
MORNING, ALTHOUGH CONFIDENCE REMAINS LOW. A FEW SHOWERS OVERNIGHT
WILL ALSO BE POSSIBLE WITH INCREASING CHANCES DURING THE DAY
TOMORROW AS TROPICAL MOISTURE STARTS TO SPREAD INTO THE REGION
INCREASING THE CHANCES FOR SOME ISOLATED THUNDERSTORMS. THE SHOWERS
WILL BECOME MORE PREVAILING TOMORROW AFTERNOON INTO THE EVENING.
REST OF UTAH AND SOUTHWEST WYOMING...VFR CONDITIONS WILL PERSIST FOR
THE ENTIRE AIRSPACE THROUGH THE PERIOD WITH SOUTHERLY FLOW. A FEW
ISOLATED SHOWERS WILL REMAIN POSSIBLE DURING THE OVERNIGHT HOURS
ACROSS THE AIRSPACE WITH INCREASING MOISTURE TOMORROW AS TROPICAL
MOISTURE SPREADS INTO THE REGION INCREASING THE CHANCES FOR SOME
ISOLATED THUNDERSTORMS. A LOW-LEVEL WIND SHEAR OF 20-25 KTS MAY
DEVELOP ACROSS NORTHERN UTAH TONIGHT INTO THE EARLY SATURDAY
MORNING, ALTHOUGH CONFIDENCE REMAINS LOW.
FIRE WEATHER
AS A STORM SYSTEM APPROACHES THE AREA, SOUTHERLY
WINDS WILL CONTINUE TO INCREASE ACROSS THE AREA TODAY, WITH
WIDESPREAD GUSTS 30-50 MPH. SCATTERED SHOWERS AND THUNDERSTORMS
WILL ALSO DEVELOP ACROSS THE AREA TODAY, WITH INCREASING CHANCES
FOR WETTING RAIN. THE STORM WILL PULL IN TROPICAL STORM REMNANTS
LATE TONIGHT THROUGH SUNDAY, WITH WIDESPREAD MODERATE TO HEAVY
RAINFALL EXPECTED. WINDS WILL ALSO LIKELY REMAIN STRONG IN
ASSOCIATION WITH THE REMNANTS. THE STORM SYSTEM WILL THEN SLOWLY
CROSS THE AREA MONDAY THROUGH EARLY WEDNESDAY, MAINTAINING AN
ACTIVE AND COOLER PATTERN WITH WIDESPREAD WETTING RAINS THROUGH
THIS TIMEFRAME. A DRYING AND WARMING TREND IS LIKELY FOR THE
LATTER PART OF THE WEEK.
SLC WATCHES/WARNINGS/ADVISORIES
UT...WIND ADVISORY UNTIL 6 AM MDT SUNDAY FOR UTZ101>109-115-116-118-
119-122-126-127.
FLOOD WATCH FROM LATE TONIGHT THROUGH MONDAY AFTERNOON FOR
UTZ101>112-114-115.
FLOOD WATCH FROM NOON MDT TODAY THROUGH MONDAY AFTERNOON FOR
UTZ113-116>131.
HIGH WIND WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT
FOR UTZ115>117-119-122-125>127.
WY...NONE.
PUBLIC...WARTHEN
AVIATION...TEKOE
FIRE WEATHER...CHENG
HYDROLOGY...
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY
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