278
FXUS65 KSLC 202223
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
323 PM MST MON JAN 20 2025
SYNOPSIS
THE COLDEST TEMPERATURES OF THE SEASON ARE SETTLING
INTO THE REGION THROUGH MIDWEEK. TEMPERATURES START TO WARM
MIDWEEK ONWARD, WITH POTENTIAL FOR ANOTHER SYSTEM BY THE WEEKEND.
SHORT TERM (THROUGH 12Z WEDNESDAY)
COLD NORTHERLY FLOW IS IN
PLACE ACROSS THE REGION, WITH THE COLDEST TEMPERATURES OF THE
SEASON IN PLACE (NEAR -20C AT 700MB). TONIGHT INTO TUESDAY MORNING
WILL BE THE COLDEST MORNING OF THE YEAR, WITH TEMPERATURES MEETING
EXTREME COLD WARNING CRITERIA ACROSS PORTIONS OF ZION NATIONAL
PARK AND GLEN CANYON RECREATION AREA (PARTICULARLY THE TOWNS OF
BULLFROG, BIG WATER, AND TICABOO). EXCESSIVE COLD WARNINGS WERE
ISSUED FOR THESE TWO LOCATIONS.
GUSTY GAP WINDS HAVE ALSO CONTINUED ACROSS LOWER WASHINGTON
COUNTY THIS AFTERNOON. THE GRADIENT IS EXPECTED TO GRADUALLY
DECREASE BETWEEN 03-05Z. A WIND ADVISORY IS IN EFFECT THROUGH 05Z
TO ACCOUNT FOR THESE GUSTY WINDS.
AFTER TUESDAY MORNING, TEMPERATURES WILL GRADUALLY MODERATE.
LONG TERM (AFTER 12Z WEDNESDAY)
LONG TERM PERIOD BEGINS WITH
THE FORECAST REGION PLACED BENEATH DEEP NORTH TO NORTHWESTERLY
FLOW BETWEEN A STOUT PACIFIC RIDGE AND DEEP LONGWAVE TROUGH
CONTINUING TO EXTEND ACROSS MUCH OF THE EASTERN TWO THIRDS OF THE
CONUS. GIVEN THE DRY NATURE OF THIS FLOW IN ADDITION TO STRONG
SURFACE HIGH PRESSURE IN VICINITY, PRECIPITATION CHANCES REMAIN
VERY LOW. THIS PATTERN WILL MORE OR LESS HOLD WEDNESDAY AND
THURSDAY, MAINTAINING TEMPERATURES NEAR TO A BIT BELOW
CLIMATOLOGICAL NORMAL. BY FRIDAY THE DEEPER FLOW BECOMES MORE
ZONAL AHEAD OF AN EMBEDDED SHORTWAVE IMPULSE DIVING SOUTHWARD OUT
OF SOUTHWEST CANADA. THIS WILL PULL A BIT MORE PACIFIC MOISTURE
INLAND AND RESULT IN A RETURN OF LOW END (MOSTLY) HIGH ELEVATION
PRECIPITATION CHANCES BY LATER IN THE DAY, BUT WARMING H7 TEMPS
WILL ALSO RESULT IN A NOTICEABLE WARMUP BACK TO ABOVE NORMAL.
MOVING INTO THE WEEKEND, FOCUS REMAINS ON THE AFOREMENTIONED
SHORTWAVE AND ITS SUBSEQUENT EVOLUTION. A ROUGH MODEL CONSENSUS
SHOWS THE SHORTWAVE AND ASSOCIATED SURFACE BOUNDARIES CONTINUING
SOUTHWARD IN SOME FASHION, BUT THEN A GOOD DEAL OF UNCERTAINTY
THEREAFTER. IN GENERAL, IT APPEARS THE SHORTWAVE WOULD RETROGRADE
SLIGHTLY INTO THE GREAT BASIN WHILE INTERACTING WITH A SEPARATE
SUBTLE IMPULSE OFF THE PACIFIC COAST, EVENTUALLY STRETCHING AND
CUTTING OFF SOMEWHERE BROADLY IN THE CENTRAL NV/CA TO AZ AREA.
EXACTLY HOW THIS PLAYS OUT WILL IMPACT THINGS LIKE MAGNITUDE AND
TRAJECTORY OF MOISTURE AND COLD AIR, AS WELL AS TIMING OF THOSE
LOWER LEVEL BOUNDARIES WHICH COULD SERVE AS A FOCUS POINT FOR MORE
ENHANCED PRECIPITATION. IF NOTHING ELSE, THERE IS PRETTY GOOD
CONSENSUS IN A COLD FRONT IN SOME FASHION, AND TEMPERATURES
AREAWIDE COOLING BACK TO LEVELS BELOW CLIMATOLOGICAL NORMAL. THERE
IS ALSO DECENT CONSENSUS THAT MOISTURE/FORCING WILL BE SUFFICIENT
FOR PRECIPITATION, BUT ONLY AROUND 25% OF ENSEMBLE MEMBERS CARRY
A SCENARIO BRINGING COVERAGE OF PRECIP MORE OR LESS AREAWIDE, WITH
REMAINING MEMBERS LESS BROAD IN COVERAGE. OF THESE SCENARIOS
THOUGH, FOR NOW SOUTH TO SOUTHWEST UTAH ACTUALLY IS THE MORE
FAVORED AREA. IN TERMS OF PRECIPITATION AMOUNTS AND PRECIPITATION
TYPE, THE AFOREMENTIONED UNCERTAINTY SURROUNDING THE EVOLUTION
WILL LIKELY RESULT IN NUMBERS/TYPES FLUCTUATING, ESPECIALLY THIS
FAR OUT. THAT SAID, WILL BE WORTH WATCHING TRENDS AS SOME OF THE
COOLER/WETTER SOLUTIONS DO BRING POTENTIAL FOR SNOW EVEN TO AREAS
AS LOW AS LOWER WASHINGTON COUNTY.
WHILE ALSO HIGHLY UNCERTAIN GIVEN QUESTIONS AROUND THE EVOLUTION
OF THE SYSTEM, IF AND WHERE IT CUTS OFF WILL BE A TREND TO
MONITOR. WHILE HARD TO QUANTIFY GIVEN THE BROAD RANGE OF
SOLUTIONS, A NUMBER OF MEMBERS CUT OFF THE LOW IN A FAVORABLE
POSITION TO INDUCE AN EASTERLY PRESSURE GRADIENT ACROSS NORTHERN
UTAH. IN TURN IF COLD AIR ADVECTION IS SUFFICIENT AND SOMETHING OF
A CRITICAL LAYER CAN FORM, THEN DOWNSLOPE OR ENHANCED CANYON
WINDS ACROSS PRONE NORTHERN UTAH VALLEYS BECOMES A CONSIDERATION.
AGAIN THOUGH, GIVEN THE HIGH DEGREE OF UNCERTAINTY IN WHAT APPEARS
TO BE A POTENTIALLY COMPLEX PATTERN EVOLUTION, JUST ANOTHER TREND
TO MONITOR.
AVIATION...KSLC
QUIET CONDITIONS LARGELY MAINTAINED WITH HIGH
PRESSURE AND DRY CONDITIONS. WINDS EXPECTED TO SHIFT TO A SE
DIRECTION BETWEEN ~03Z-06Z TUE, AND ARE FAVORED TO THEN REMAIN SE
TO S THEREAFTER THROUGH TUE. A BIT OF MID/UPPER MOISTURE WILL
RESULT IN A CORRESPONDING INCREASE IN VFR CLOUD COVER AS WELL
THROUGH TUE.
REST OF UTAH AND SOUTHWEST WYOMING
A FAIRLY QUIET TAF PERIOD
EXPECTED WITH HIGH PRESSURE RESULTING IN DRY AND VERY LIKELY VFR
CONDITIONS THROUGHOUT. WINDS WILL LARGELY FOLLOW A TYPICAL DIURNAL
PATTERN IN REGARDS TO MAGNITUDES, BUT FAVOR A MORE SOUTHERLY
DIRECTIONAL COMPONENT DURING THE DAY TUESDAY, PARTICULARLY AT
NORTHERN TERMINALS. A SLIGHT INCREASE IN MID/UPPER LEVEL MOISTURE
WILL RESULT IN A CORRESPONDING INCREASE IN CLOUD COVER AS WELL ON
TUESDAY, AGAIN MOSTLY AT NORTHERN TERMINALS.
SLC WATCHES/WARNINGS/ADVISORIES
UT...WIND ADVISORY UNTIL 10 PM MST THIS EVENING FOR UTZ123.
EXTREME COLD WARNING FROM 11 PM THIS EVENING TO 10 AM MST
TUESDAY FOR UTZ124-131.
WY...NONE.
KRUSE/WARTHEN
FOR MORE INFORMATION FROM NOAA'S NATIONAL WEATHER SERVICE
VISIT... HTTP://WEATHER.GOV/SALTLAKECITY
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