332
FXUS65 KBOI 242133
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
233 PM MST WED DEC 24 2025
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
DEEP MOIST SOUTHERLY
FLOW ON THE EAST SIDE OF AN UPPER LEVEL TROUGH AND STORM SYSTEM
WILL CONTINUE OVER SOUTHWESTERN IDAHO AND SOUTHEASTERN OREGON
TONIGHT THROUGH CHRISTMAS. THE STRONG SURFACE PRESSURE GRADIENT
RESPONSIBLE FOR WINDY CONDITIONS WILL RELAX A BIT TONIGHT AND
WINDS WILL SUBSIDE THIS EVENING. THE MOIST FLOW WILL BRING
INTERMITTENT PERIODS OF RAIN TO THE AREA AS WELL...EVEN IN THE
MOUNTAINS WHERE SNOW LEVELS WILL REMAIN ABOVE 6500 FEET THROUGH
CHRISTMAS. TEMPERATURES WILL COOL A FEW DEGREES IN THE RAIN BUT
WILL STILL BE ABOUT 15 DEGREES ABOVE NORMAL TOMORROW.
TEMPERATURES WILL COOL ANOTHER BY ANOTHER 5 TO 10 DEGREES ON
FRIDAY AND SNOW LEVELS WILL COME DOWN TO THE 4000 TO 5000 FOOT
RANGE AS THE MAIN UPPER LEVEL TROUGH AND STORM SYSTEM MOVE
THROUGH THE AREA. THIS WILL ALLOW FOR SOME ACCUMULATIONS OF
SNOW ABOVE THESE ELEVATIONS. THE BOISE AND WEST CENTRAL
MOUNTAINS WILL SEE THE MOST SNOW ON FRIDAY WITH SNOW EXPECTED ON
ROADS AND IN MOUNTAIN COMMUNITIES.
LONG TERM...SATURDAY THROUGH WEDNESDAY
TWAS THE DAY BEFORE
CHRISTMAS, WHEN ALL THROUGH THE OFFICE. NOT A CREATURE WAS
STIRRING... EXCEPT FOR YOUR FRIENDLY NEIGHBORHOOD METEOROLOGISTS OF
COURSE! SATURDAY WILL FEATURE LINGERING PRECIPITATION OVER THE
MOUNTAINS AS AN UPPER LEVEL TROUGH MOVES EAST, DETERIORATING UPPER
LEVEL FORCING AND MOISTURE WILL LEAVE THE LOCAL OROGRAPHIC FORCING
AS THE MAIN DRIVER OF PRECIPITATION. WITH SNOW LEVELS AT VALLEY
FLOORS, SNOW IS LIKELY TO BE THE DOMINANT PRECIP TYPE. WITH
DECREASING MOISTURE IN NORTHWEST FLOW ALOFT, MINIMAL ADDITIONAL
ACCUMULATIONS ARE EXPECTED SATURDAY, WITH UP TO 1.5 INCHES ACROSS
THE HIGHEST PEAKS.
SUNDAY AND BEYOND, CONSENSUS IS HIGH ON A SIGNIFICANT PATTERN
CHANGE. AS THE TROUGH PROPAGATES EAST, IT WILL UNDERGO A WAVE BREAK
CLOSING OFF INTO A RETROGRADING LOW OVER THE PACIFIC. WITH RIDGING
BUILDING IN OVER IT, OUR AREA WILL GET PLACED IN THE DRY REGION OF A
REX BLOCK. WITH STRONG SUBSIDENCE UNDER THE HIGH PRESSURE, LIGHT
WINDS, AND A LOW SUN ANGLE, MIXING HEIGHTS WILL TANK AND GIVE WAY
FOR A PROLONGED VALLEY INVERSION. THIS INVERSION, PAIRED WITH
INCREASED SURFACE MOISTURE FROM THE ACTIVE PATTERN AS OF LATE, MEAN
THAT FOG/LOW STRATUS WILL LIKELY BE IN PLAY THROUGHOUT THE MAJORITY
OF THE LONG TERM PERIOD. THIS SET UP ALSO FAVORS COLD POOLING IN THE
VALLEYS, WHICH WOULD LOWER TEMPERATURES VERSUS WHAT IS CURRENTLY
FORECAST... ESPECIALLY IF IT IS COMBINED WITH REDUCED SOLAR HEATING
UNDER A STRATUS CLOUD DECK. GUIDANCE HAS BEEN TRENDING DOWNWARD WITH
THE HIGH TEMPERATURES, PERHAPS A SIGN THAT THEY ARE STARTING TO PICK
UP ON A COLD POOL? EITHER WAY, TEMPERATURES MAY STILL BE A TAD
OVERDONE IN THE LONG TERM. LOW STRATUS COULD ALSO KEEP TEMPERATURES
A FEW DEGREES WARMER THAN THE CURRENT FORECAST.
AVIATION
PRECIPITATION CONTINUING ACROSS E-OREGON AND SW-IDAHO
THROUGH THE EVENING. DECREASING IN COVERAGE AFTER THU/06Z. VFR/MVFR
IN RAIN, MVFR/IFR IN MOUNTAIN SNOW, MTNS OBSCURED. AREA OF FOG/LOW
STRATUS OVERNIGHT IN SHELTERED VALLEYS. SNOW LEVELS: 6.5-8.5 KFT
MSL. SURFACE WINDS: S-SE 10-20 KT WITH GUSTS TO 25-35 KT, LOCALLY
HIGHER NEAR THE NV BORDER AND E-CENTRAL OREGON. DECREASING TO S-SE 5-
15 KT OVERNIGHT. WINDS ALOFT AT 10 KFT MSL: S-SW 40-60 KT.
KBOI...LIGHT RAIN THIS AFTERNOON/EVENING. VFR CONDITIONS EXPECTED IN
AND OUT OF PRECIP. SURFACE WINDS: SE 15-22 KT WITH GUSTS UP TO 32 KT
THIS AFTERNOON. DECREASING THIS EVENING TO SE 8-12 KT BY AROUND
THU/06Z.
BOI WATCHES/WARNINGS/ADVISORIES
ID...WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON IDZ015-029-030.
OR...WIND ADVISORY UNTIL 4 PM MST /3 PM PST/ THIS AFTERNOON
ORZ061>063.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
SHORT TERM...JB
LONG TERM....NF
AVIATION.....NF
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