453
FXUS65 KBOI 250257
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
857 PM MDT FRI OCT 24 2025
DISCUSSION
A FRONTAL SYSTEM APPROACHING FROM THE NORTHWEST
AS THE FLOW ALOFT TURNS ZONAL. A WARM FRONT WILL BRING SHOWERS
ON SATURDAY MORNING WITH SNOW LEVELS AROUND 7000-8000 FT MSL
INITIALLY. WEST-SOUTHWEST WINDS REALLY RAMP UP ON SATURDAY
AFTERNOON WITH 25-35 MPH ACROSS THE AREA, AND GUSTS UP TO 50
MPH. SHOWERS INCREASE AHEAD OF THE COLD FRONT EARLY SATURDAY
MORNING ACROSS EASTERN OR AND SHORTLY THEREAFTER IN SOUTHWEST
ID. AS SHOWERS INCREASE, THE RAIN SHOWERS WILL AID IN MIXING THE
STRONGER WINDS ALOFT DOWN TO THE SURFACE, WITH GUSTS UP TO 50
MPH, PARTICULARLY ALONG THE COLD FRONT. ISOLATED THUNDERSTORMS
EXPECTED TO DEVELOP ALONG THE COLD FRONT IN THE AFTERNOON. A
SECONDARY SHORTWAVE ARRIVES ON SUNDAY WITH ANOTHER ROUND OF
PRECIPITATION OVER THE AREA, WITH SNOW LEVELS AROUND 3500-5000
FEET. FORECAST UPDATES OUT SHORTLY, MAINLY FOR INCREASED WINDS
ON SATURDAY.
AVIATION
VFR. CLOUD CEILINGS LOWERING GRADUALLY TONIGHT
THROUGH TOMORROW MORNING, BRINGING MVFR CONDITIONS FOR HIGHER
ELEVATION LOCATIONS. PRECIPITATION DEVELOPING OVER SE OR AND
EXPECTED FOR SW ID STARTING 06Z AND CONTINUING THROUGH
MORNING/EARLY AFTERNOON. LLWS CONCERN FOR ALL LOCATIONS WITH
PASSING WARM FRONT EARLY TOMORROW MORNING. A COLD FRONT WILL
BRING ISOLATED THUNDERSTORMS TOMORROW AFTERNOON. STRONGER W-SW
WIND GUSTS UP TO 40 KT FOR MOST LOCATIONS TOMORROW AFTERNOON.
SURFACE WINDS: S-SE 10-15 KT WITH GUSTS 20-25 KT TONIGHT AND
TOMORROW MORNING, BECOMING SW 10-15 KT WITH GUSTS 30-40 KT.
WINDS ALOFT AT 10KFT MSL: SW 35-50 KT.
KBOI...VFR. INCREASING CLOUD COVER TONIGHT. MVFR CEILINGS
POSSIBLE WITH RAIN SHOWERS AFTER 10Z. LLWS IS A CONCERN AHEAD
COLD FRONT PASSAGE, MAXIMIZED TOMORROW LATE MORNING. AFTERNOON
ISOLATED THUNDERSTORMS EXPECTED CLOSE TO SUN/00Z, WITH SW GUSTS
UP TO 30 KT. SURFACE WINDS: SE 10-15 KT WITH GUSTS UP TO 25 KT
TONIGHT THROUGH TOMORROW MORNING/EARLY AFTERNOON, BECOMING SW
10-15 KT WITH GUSTS UP TO 30 KT AFTER 21Z.
SUNDAY OUTLOOK...WIDESPREAD RAIN AND SNOW LATE SATURDAY THROUGH
SUNDAY. SNOW LEVELS LOWERING TO 3500-5000 FEET MSL SUNDAY. AREAS
OF MVFR/IFR FLIGHT CATEGORIES IN LOW CLOUDS AND PRECIPITATION.
MOUNTAINS FREQUENTLY OBSCURED. SLIGHT CHANCE OF ISOLATED TO
SCATTERED THUNDERSTORMS SATURDAY LATE AFTERNOON/EVENING. PATCHY
FOG IN VALLEYS THROUGH OVERNIGHT/EARLY MORNING HOURS SUNDAY.
SURFACE WINDS SW-SE 10-15 KT WITH GUSTS 30-40 KT FOR MOST AREAS
LATE SATURDAY AND MOSTLY VARIABLE SUNDAY WITH GUSTS 20-30 KT
ALONG OR-ID- NV BORDER AND LOWER MAGIC VALLEY.
PREV DISCUSSION
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT...INCREASING CLOUDS
THIS AFTERNOON AND EVENING PRECEDE THE NEXT STRONG PACIFIC
STORM SYSTEM FOR THE WEEKEND. THE PRIMARY IMPACTS FROM THE STORM
LOOK TO BE STRONG WINDS ON SATURDAY AFTERNOON WITH ACCUMULATING
SNOWFALL DOWN TO 4000 FEET ON SUNDAY.
THERE WILL BE TWO FRONTAL PASSAGES ON SATURDAY: THE FIRST
PASSAGE THROUGH SATURDAY MORNING WILL BRING MOSTLY RAIN UP TO
7500 FEET, FOLLOWED BY A MUCH STRONGER SECOND FRONT SATURDAY
AFTERNOON AND EVENING. THE SECOND FRONT WILL USHER IN MUCH
COLDER AIR AND WIDESPREAD RAIN AND SNOW, HEAVIEST IN NORTHERN
AREAS. WIND MAY BE THE MOST IMPACTFUL FEATURE, WITH MODELS
AVERAGING 40 TO 50 MPH GUSTS FROM THE SOUTHWEST, WHICH IS
SUFFICIENT TO CONTINUE THE WIND ADVISORY IN HARNEY AND MALHEUR
COUNTIES, THE OWYHEE MOUNTAINS, AND SOUTHERN HIGHLAND ZONES. IN
ADDITION, SPC HAS ADDED MOST OF THE AREA INTO A MARGINAL RISK
FOR ISOLATED SEVERE THUNDERSTORMS SATURDAY AFTERNOON WITH
CONDITIONS FAVORABLE FOR ISOLATED WIND GUSTS UP TO 60 MPH.
OVERALL, PRECIPITATION AND SNOW AMOUNTS CAME IN ABOUT 20
PERCENT LOWER THAN PREVIOUS FORECASTS ACROSS MUCH OF THE AREA,
LIKELY DUE TO THE FASTER MOVEMENT OF THE FRONTAL PASSAGE ON
SATURDAY. SHADOWING FROM THE OWYHEES DUE TO STRONG MID LEVEL
WINDS COULD LIMIT PRECIPITATION AMOUNTS FOR PARTS OF THE
TREASURE VALLEY ON SATURDAY, THOUGH UP TO 0.20 INCH IS POSSIBLE.
RAIN WILL SWITCH TO SNOW IN THE CENTRAL MOUNTAINS LATE SATURDAY
NIGHT POST COLD FRONTAL PASSAGE, WITH SNOW LEVELS FALLING TO
NEAR 4000 FEET. HIGHER ELEVATIONS (ABOVE 6500 FEET) COULD SEE
AROUND A FOOT OF SNOWFALL THROUGH MONDAY MORNING. THE LOWER
MOUNTAIN VALLEYS WILL SEE FAR LESS, WITH UP TO 1 TO 3 INCHES
POSSIBLE ABOVE 4500 FEET. MCCALL HAS ABOUT A 10 PERCENT CHANCE
TO EXCEED 4 INCHES OF SNOW SUNDAY.
LONG TERM...MONDAY THROUGH FRIDAY...THE UPPER-LEVEL TROUGH THAT
WILL CAUSE THE WEEKEND WEATHER WILL BE PUSHING WELL OUT OF OUR AREA,
GIVING WAY TO WEAK UPPER-LEVEL RIDGING TO BEGIN BUILDING STARTING
MONDAY. BEFORE THIS PROGRESSES INTO A MORE POTENT RIDGE OVER THE
AREA, NORTHWESTERLY FLOW ALOFT, COMBINED WITH LINGERING MOISTURE,
WILL KEEP PRECIPITATION CHANCES MENTIONABLE MONDAY AND TUESDAY.
WHILE I THINK THE POPS ARE A BIT OVERDONE BY TAKING PREVIOUS MODEL
RUNS INTO ACCOUNT, I DO BELIEVE THERE IS STILL A CHANCE GIVEN THE
SETUP. SNOW LEVELS MONDAY RAISE FROM 3500-5000 FT MSL TO 5000-7000
FT MSL BY TUESDAY MORNING. BY MIDDAY TUESDAY, THE RIDGE AXIS WILL BE
WELL OVERHEAD. THE EFFECT THIS HAS ON ANOTHER SHORTWAVE TROUGH
PASSING ALONG OUR NORTHERN COUNTIES IS SHOWN DIFFERENTLY IN LONG
RANGE MODELS, WHERE THE GFS HAS A MUCH DEEPER SYSTEM COMPARED TO THE
ECMWF WHICH KEEPS IT WELL NORTH. GIVEN THE DISCREPANCY, IT IS
UNSURPRISING THAT PRECIPITATION CHANCES ARE STILL POPULATING IN OUR
NORTHERN HIGHER ELEVATION REGIONS. ONCE THIS DISTURBANCE PASSES TO
THE EAST BY THU/12Z, ANOTHER SHORTWAVE RIDGE LOOKS TO BUILD IN
BEFORE YET ANOTHER UPPER-LEVEL TROUGH IMPACTS THE PACIFIC
NORTHWEST.
PRELIMINARY POINT TEMPS/POPS
BAKER CITY 38 58 25 48 / 80 100 50 60
BOISE 48 61 39 51 / 30 90 70 60
BURNS 35 57 21 45 / 80 90 30 70
CALDWELL 47 64 37 54 / 50 90 60 60
FAIRFIELD 32 49 23 43 / 0 70 90 50
IDAHO CITY 35 55 25 48 / 40 100 90 70
JEROME 43 56 36 45 / 0 30 70 50
MCCALL 34 46 25 39 / 80 100 90 80
MOUNTAIN HOME 45 61 36 51 / 10 60 80 60
ONTARIO 45 62 35 53 / 70 90 50 60
ROME 41 62 31 50 / 50 70 50 60
TWIN FALLS 44 60 35 47 / 0 30 70 60
BOI WATCHES/WARNINGS/ADVISORIES
ID...WIND ADVISORY FROM 3 PM TO 9 PM MDT SATURDAY IDZ015-029.
OR...WIND ADVISORY FROM 3 PM MDT /2 PM PDT/ TO 9 PM MDT /8 PM PDT/
SATURDAY ORZ061-063.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
DISCUSSION...KA
AVIATION.....JY
SHORT TERM...JDS
LONG TERM....CH
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