519
FXUS65 KBOI 241612
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1012 AM MDT FRI OCT 24 2025
DISCUSSION
DRY AND MILD CONDITIONS PREVAIL TODAY, WITH
INCREASING CLOUDS THIS AFTERNOON AHEAD OF THE NEXT PACIFIC STORM
SYSTEM FOR THE WEEKEND. INCREASING SOUTHERLY WINDS TODAY WILL
HELP PUSH TEMPERATURES CLOSE TO 70 DEGREES IN THE LOWER VALLEYS.
NO SIGNIFICANT CHANGE IS SEEN IN THE LATEST GUIDANCE FOR THIS
WEEKEND'S SIGNIFICANT STORM SYSTEM. THE MAIN IMPACTS FROM THE
STORM LOOK TO BE STRONG WINDS ON SATURDAY 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, ALONG WITH ISOLATED
THUNDERSTORMS.
WIND LOOK TO BE THE MOST IMPACTFUL FEATURE, WITH MODELS
AVERAGING 40 TO 50 MPH GUSTS FROM THE SOUTHWEST, WHICH IS
SUFFICIENT FOR A WIND ADVISORY IN HARNEY AND MALHEUR COUNTIES
AND THE OWYHEE MOUNTAINS. 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 0.25 INCH
IS NOT OUT OF THE QUESTION. 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 TOTAL
THROUGH MONDAY MORNING. THE LOWER MOUNTAIN VALLEYS WILL SEE FAR
LESS, WITH UP TO 1 TO 3 INCHES POSSIBLE ABOVE 4000 FEET. MCCALL
HAS ABOUT A 20 PERCENT CHANCE TO EXCEED 4 INCHES OF SNOW
SUNDAY/MONDAY.
THIS WILL BE FURTHER ADDRESSED IN THE AFTERNOON PACKAGE, BUT
ADDITIONAL HEADLINES ARE NOT ANTICIPATED. NO UPDATES ARE NEEDED
AT THIS TIME.
AVIATION
VFR. CLOUD CEILINGS BEGINNING TO LOWER GRADUALLY
LATE FRIDAY/SATURDAY MORNING TO MVFR CONDITIONS BY SATURDAY FOR
MOST LOCATIONS. LLWS CONCERN FOR ALL LOCATIONS WITH PASSING COLD
FRONT EARLY SATURDAY MORNING. SURFACE WINDS: S-SE 10-15 KT WITH
GUSTS 20- 25 KT BEGINNING THIS MORNING/EARLY AFTERNOON. WINDS
ALOFT AT 10KFT MSL: SW 10-20KT, INCREASING TO SW 25-40 KT
SAT/00Z.
KBOI...VFR. INCREASING CLOUD COVER TODAY. MVFR CHANCES HEIGHTEN
WITH PASSAGE OF COLD FRONT AFTER SAT/10Z. CHANCE OF RAIN
INCREASES GREATLY AFTER COLD FRONT (70% CHANCE). LLWS WILL ALSO
BE CLOSELY EVALUATED FOR THIS PERIOD. SURFACE WINDS: SE 10-15 KT
WITH GUSTS UP TO 25 KT POSSIBLE THROUGH SAT/07Z.
WEEKEND OUTLOOK...WIDESPREAD RAIN AND SNOW LATE FRIDAY NIGHT
THROUGH SUNDAY NIGHT. SNOW LEVELS LOWERING TO 4000-5000 FEET MSL
SUNDAY. AREAS OF MVFR/IFR FLIGHT CATEGORIES IN LOW CLOUDS AND
PRECIPITATION. MOUNTAINS FREQUENTLY OBSCURED. SLIGHT CHANCE OF
THUNDERSTORMS SATURDAY EVENING. PATCHY FOG IN VALLEYS THROUGH
OVERNIGHT/EARLY MORNING HOURS. SURFACE WINDS SW-SE 10-15 KT WITH
GUSTS 20-30 KT FOR MOST AREAS. LLWS PROBABLE SATURDAY MORNING.
STRONGEST GUSTS UP TO 40 KT EXPECTED ALONG EASTERN OR AND
MOUNTAINS THROUGH SATURDAY.
PREV DISCUSSION
SHORT TERM...TODAY THROUGH SUNDAY NIGHT...ONE LAST DAY OF DRY,
MILD WEATHER BEFORE A DEEP GULF OF ALASKA UPPER TROUGH COMES IN
THIS WEEKEND. THE TROUGH WILL SEND A SURFACE COLD FRONT ACROSS
OUR CWA SATURDAY THROUGH SATURDAY EVENING, BRINGING COLDER AIR
AND WIDESPREAD RAIN AND SNOW, HEAVIEST IN NORTHERN AREAS, ALSO
ISOLATED THUNDERSTORMS, AND STRONG WIND GUSTS IN SOUTHEAST
OREGON AND THE OWYHEE MOUNTAINS SATURDAY AFTERNOON AND EVENING.
WIND MAY BE THE MOST IMPACTFUL FEATURE WITH MODELS AVERAGING 40
TO 50 MPH GUSTS FROM THE SOUTHWEST, ENOUGH FOR A WIND ADVISORY
IN HARNEY AND MALHEUR COUNTIES AND THE OWYHEE MOUNTAINS. THE
HRRR MODEL HAS 50 TO 60 MPH GUSTS OVER ALL OF EASTERN OREGON
AND ABOUT HALF OF WESTERN IDAHO BUT THAT MODEL IS A HIGH-END
OUTLIER. OUR ADVISORY REFLECTS THE MODEL CONSENSUS. TOTAL
FORECAST PCPN LATE TONIGHT THROUGH MONDAY EVENING HASN'T CHANGED
MUCH SINCE YESTERDAY, STILL RANGING FROM 1.00 TO 2.00 INCHES IN
IDAHO NORTH OF THE SNAKE BASIN, AND .30 TO .60 INCH ELSEWHERE
WITH .60 TO 1.00 INCH IN THE MOUNTAINS. SOUTHWEST WINDS ALOFT
MAY CAUSE SHADOWING IN THE SNAKE BASIN, BUT EVEN THERE AT LEAST
30 INCH OF RAIN IS EXPECTED. SNOW LEVEL WILL STAY ABOVE 6500
FEET MSL THROUGH SATURDAY EVENING, THEN LOWER SATURDAY NIGHT
BEHIND THE COLD FRONT TO 4000 FEET NORTH TO 5000 FEET SOUTH
SUNDAY THROUGH MONDAY. SNOW WILL THEN ACCUMULATE 4 TO 12 INCHES
IN THE IDAHO MOUNTAINS NORTH OF THE SNAKE BASIN, WITH POST-
FRONTAL PCPN CONTINUING SUNDAY INTO MONDAY. MCCALL/ID SHOULD GET
3-4 INCHES NEW SNOW, WITH THE MAIN SNOWFALL SUNDAY NIGHT. HIGH
TEMPS TODAY WILL BE GENERALLY 60 TO 70 DEGREES, THEN 10 TO 15
DEGREES COLDER SATURDAY, AND ANOTHER 4 TO 8 DEGREES COLDER
SUNDAY. CLOUDS AND WINDS WILL KEEP LOW TEMPS FROM BECOMING TOO
COLD, GENERALLY UPPER 30S THROUGH 40S SATURDAY MORNING, UPPER
20S AND 30S SUNDAY, AND 20S TO MID 30S MONDAY.
LONG TERM...MONDAY THROUGH FRIDAY...PRECIPITATION CHANCES
WILL REMAIN ELEVATED COME MONDAY, AS DETERMINISTIC AND ENSEMBLE
GUIDANCE HINT AT A SHORTWAVE CROSSING OVER OUR AREA. THIS
SHORTWAVE, PAIRED WITH LINGERING MOISTURE OVER THE AREA, WILL
ALLOW FOR A 20-40% CHANCE OF PRECIPITATION SOUTHWEST OF A LINE
ROUGHLY FROM CENTERVILLE,ID TO CAMBRIDGE,ID. NORTHEAST OF THAT
LINE, CHANCES OF PRECIPITATION WILL RANGE FROM 40-60%. FOLLOWING
THE COLD FRONTAL PASSAGE IN THE SHORT TERM, SNOW LEVELS WILL BE
AT 4000-5000 FT MSL. THROUGHOUT THE DAY MONDAY, ELEVATIONS
ABOVE 5500 FT MSL IN THE WEST CENTRAL MOUNTAINS HAVE A 40-70%
CHANCE OF SEEING AT LEAST AN ADDITIONAL 4 INCHES OF SNOW
(CHANCES INCREASING WITH ELEVATION). ISOLATED SHOWERS WILL
CONTINUE OVER BAKER, VALLEY, AND ADAMS COUNTIES THROUGH
WEDNESDAY MORNING. OTHERWISE, OUR AREA IS LOOKING TO REMAIN
DRY AS A LOW-AMPLITUDE RIDGE BUILDS OVER THE GREAT BASIN.
PRECIPITATION CHANCES WILL BEGIN TO INCREASE FRIDAY AS THE NEXT
SYSTEM APPROACHES. HOWEVER, THERE IS MUCH TO BE RESOLVED IN THE
DAYS TO COME. TEMPERATURES ON MONDAY WILL BE 5-10 DEGREES BELOW
NORMAL, BEFORE INCREASING TO MORE SEASONABLE VALUES TUESDAY AND
BEYOND.
PRELIMINARY POINT TEMPS/POPS
BAKER CITY 42 55 31 49 / 50 100 30 60
BOISE 50 61 40 52 / 10 90 90 50
BURNS 38 56 26 48 / 70 90 20 70
CALDWELL 48 62 39 54 / 20 80 70 40
FAIRFIELD 35 51 29 43 / 0 90 90 60
IDAHO CITY 37 54 29 48 / 20 100 100 70
JEROME 43 57 36 49 / 0 30 70 60
MCCALL 35 44 28 38 / 80 100 90 80
MOUNTAIN HOME 47 62 38 53 / 10 60 70 50
ONTARIO 46 62 38 54 / 30 90 60 40
ROME 44 62 32 54 / 30 60 40 50
TWIN FALLS 46 59 37 51 / 0 30 70 60
BOI WATCHES/WARNINGS/ADVISORIES
ID...WIND ADVISORY FROM 3 PM TO 9 PM MDT SATURDAY IDZ029.
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...JDS
AVIATION.....CH
SHORT TERM...LC
LONG TERM....NF
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