925
FXUS65 KSLC 061912
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
112 PM MDT TUE OCT 6 2026
.KEY MESSAGES..
- ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL
IMPACT PORTIONS OF CENTRAL AND SOUTHERN UTAH THROUGH THIS
EVENING. GUSTY OUTFLOW WINDS IN EXCESS OF 40 MPH AND BRIEF HEAVY
RAIN WILL BE THE MAIN THREATS.
- 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.
- CURRENT GUIDANCE SUGGESTS MUCH OF UTAH WILL SEE BETWEEN 1 TO 2
INCHES OF RAIN, WITH LOCALLY HIGHER AMOUNTS IN EXCESS OF 2.5
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.
DISCUSSION
A WEAK SHORTWAVE TROUGH IS CURRENTLY SHIFTING ACROSS
THE REGION, BRINGING AN AREA OF SHOWERS TO PORTIONS OF CENTRAL AND
SOUTHERN UTAH. CAMS SUGGEST ADDITIONAL DEVELOPMENT AHEAD OF THIS
SHORTWAVE WILL OCCUR ACROSS THE SOUTHERN MOUNTAINS. GIVEN SURFACE
DEWPOINTS IN THE 30S TO LOWER 40S AND MEDIOCRE INSTABILITY,
EXPECT THIS CONVECTION TO BE MAINLY OUTFLOW DOMINANT, TRENDING
TOWARD THE ADJACENT LOWER DESERT AREAS THROUGH EARLY EVENING. MAIN
THREAT WILL BE GUSTY, MICROBURST WINDS IN EXCESS OF 40 MPH AND
BRIEF HEAVY RAIN.
ATTENTION WILL THEN TURN TO INCREASING POTENTIAL FOR WIDESPREAD
HEAVY RAIN ACROSS THE REGION FROM AS EARLY AS LATE SATURDAY
THROUGH AT LEAST TUESDAY. A STRONG UPPER LEVEL TROUGH SHIFTING
INTO THE PACIFIC NORTHWEST WILL COMBINE WITH NOW HURRICANE RACHEL
TO BRING DEEP TROPICAL MOISTURE INTO UTAH, AS EARLY AS SATURDAY
NIGHT. GUIDANCE HAS SHIFTED QUITE A BIT TOWARD THIS PHASED
SOLUTION, WITH ONLY 10% OF MEMBERS NOW FAVORING A MORE
PROGRESSIVE, DRIER SOLUTION.
HOW LONG THE MOISTURE STICKS AROUND IS ANOTHER QUESTION. AROUND
50% OF MEMBERS SUGGEST THE TROUGH, ALONG WITH PW ANOMALIES ON THE
ORDER OF 98+ PERCENTILE REMAINS OVER THE WEST THROUGH AT LEAST
TUESDAY NIGHT. THE REMAINING 50% OF MEMBERS ARE MORE PROGRESSIVE,
CLEARING THE TROUGH SOMETIME MONDAY.
REGARDLESS, CONFIDENCE IS HIGH WITH 90% OF MEMBERS SHOWING A
VARIATION THAT PHASES THE STRONG PACIFIC TROUGH WITH TROPICAL
MOISTURE ASSOCIATED WITH RACHEL, THAT UTAH WILL SEE A PERIOD OF
MODERATE TO HEAVY RAINFALL. CURRENT GUIDANCE SUGGESTS 1 TO 2
INCHES OF RAIN ACROSS MUCH OF UTAH, WITH LOCALLY IN EXCESS OF
2.5-3.00 INCHES, PARTICULARLY ACROSS SOUTHERN UTAH AS THE MOST
PROBABLE RANGE FOR THE EVENT. WITH COLDER TEMPERATURES ASSOCIATED
WITH THIS PACIFIC TROUGH, SOME HIGHER ELEVATION LOCATIONS ABOVE
8500 FEET MAY SEE LIGHT SNOW ACCUMULATIONS TUESDAY.
GIVEN IT IS ONLY TUESDAY, NO PRODUCTS WILL BE ISSUED FOR THIS
ENHANCED FLASH FLOOD THREAT, BUT THOSE WITH OUTDOOR PLANS FOR THE
HOLIDAY WEEKEND, PARTICULARLY SUNDAY AND MONDAY, SHOULD BE
PREPARED TO MAKE ALTERNATE ARRANGEMENTS AS MANY AREAS OF SOUTHERN
UTAH SUCH AS SLOT CANYONS, NORMALLY DRY WASHES, STREAMS AND AREAS
NEAR RECENT BURN SCARS MAY SEE A HEIGHTENED THREAT OF FLASH
FLOODING. RISES ARE ALSO LIKELY ON ALL AREA STREAMS AND RIVERS.
AVIATION...KSLC
THE SLC TERMINAL WILL SEE VFR CONDITIONS
THROUGHOUT THE DAY WITH SOME SCATTERED CLOUDS. SOUTHERLY WINDS ARE
EXPECTED TO SHIFT TO THE NORTHWEST BETWEEN 20Z AND 21Z BEFORE
RETURNING TO THE SOUTH BETWEEN 03Z AND 05Z. THERE IS A 20 PERCENT
CHANCE THAT OUTFLOW FROM STORMS DEVELOPING THIS AFTERNOON OVER THE
HIGHER TERRAIN WILL BRING PERIODS OF GUSTY AND ERRATIC WINDS,
WITH THIS MOST LIKELY OCCURRING MID TO LATE AFTERNOON.
REST OF UTAH AND SOUTHWEST WYOMING...VFR CONDITIONS WILL PREVAIL
ACROSS THE AIRSPACE THROUGH THE EVENING WITH GENERALLY LIGHT AND
TERRAIN DRIVEN WINDS. ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP OVER THE HIGHER TERRAIN THIS AFTERNOON
BRINGING LIGHTNING, BRIEF MOUNTAIN OBSCURATIONS, AND GUSTY AND
ERRATIC WINDS TO ANY AREAS THEY PASS OVER THROUGH THE EARLY EVENING.
FIRE WEATHER
A WEAK SYSTEM WILL BRING ISOLATED TO WIDELY
SCATTERED SHOWERS AND THUNDERSTORMS TO CENTRAL AND SOUTHERN UTAH
THROUGH THIS EVENING. RELATIVELY DRY AND WARM CONDITIONS WILL
SEGUE TO AN INCREASING THREAT OF WIDESPREAD MODERATE TO HEAVY RAIN
AS A STRONG PACIFIC SYSTEM PHASES WITH TROPICAL CYCLONE TO BRING
DEEP TROPICAL MOISTURE TO UTAH. MODERATE TO HEAVY PRECIPITATION
WILL BEGIN AS EARLY AS SATURDAY NIGHT AND CONTINUE THROUGH AT
LEAST TUESDAY.
SLC WATCHES/WARNINGS/ADVISORIES
UT...NONE.
WY...NONE.
KRUSE/TRAPHAGAN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE
VISIT... HTTP://WEATHER.GOV/SALTLAKECITY
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