614
FXUS65 KBOI 241004
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
304 AM MST WED DEC 24 2025
SHORT TERM...TODAY THROUGH FRIDAY NIGHT
MILD TEMPERATURES
AND UNSETTLED CONDITIONS WILL PERSIST THROUGH THE CHRISTMAS
HOLIDAY AS A STRONG PACIFIC SYSTEM MOVES THROUGH THE REGION. A
COLD FRONT WILL MOVE ACROSS THE AREA THIS MORNING, CROSSING
SOUTHEAST OREGON FROM NOW THROUGH SUNRISE AND SOUTHWEST IDAHO
LATER THIS MORNING. WIND SPEEDS OF 25 TO 35 MPH WITH GUSTS UP TO
55 MPH ARE LIKELY, PARTICULARLY ACROSS MUCH OF SOUTHEAST
OREGON, THE WESTERN MAGIC VALLEY, AND THE HIGHLANDS NEAR THE
NEVADA BORDER WITH AND BEHIND THE FRONTAL PASSAGE. A WIND
ADVISORY REMAINS IN EFFECT FOR THESE AREAS THROUGH WEDNESDAY
AFTERNOON.
PRECIPITATION WILL ACCOMPANY THE FRONTAL PASSAGE, WITH THE
HEAVIEST AMOUNTS EXPECTED ALONG THE FRONT ITSELF. WHILE
SUBTROPICAL MOISTURE IS BEING PULLED INTO THE SYSTEM, STRONG
WESTERLY FLOW ALOFT WILL LIKELY CREATE A RAIN SHADOWING EFFECT
FOR THE TREASURE VALLEY, LIMITING TOTALS THERE TO AROUND 0.10
INCHES. IN CONTRAST, THE MOUNTAINS OF CENTRAL IDAHO AND
NORTHEAST OREGON COULD SEE 0.25 TO 0.50 INCHES OF LIQUID
EQUIVALENT. SNOW LEVELS WILL REMAIN HIGH AHEAD OF THE FRONT,
GENERALLY BETWEEN 7000 AND 8000 FEET, MEANING RAIN WILL BE THE
PRIMARY PRECIPITATION TYPE FOR MOST INHABITED AREAS. BEHIND THE
FRONT, SNOW LEVELS WILL DROP TO BETWEEN 3500 AND 5500 FEET BY
WEDNESDAY NIGHT, ALLOWING FOR LIGHT SNOW ACCUMULATIONS IN THE
MOUNTAINS AND HIGHER FOOTHILLS.
FOR CHRISTMAS DAY, A WEAK RIDGE WILL PROVIDE A BRIEF RESPITE
FOR THE LOWER VALLEYS EARLY, THOUGH A 70 PERCENT CHANCE OF RAIN
AND HIGH ELEVATION SNOW WILL CONTINUE FOR THE CENTRAL IDAHO
MOUNTAINS. HIGH TEMPERATURES WILL REMAIN 10 TO 15 DEGREES ABOVE
SEASONAL NORMALS, WITH VALLEY HIGHS REACHING NEAR RECORD HIGHS
FOR SEVERAL LOCATIONS IN THE UPPER 50S. THE RECORD HIGH FOR
CHRISTMAS DAY IN BOISE IS 60 DEGREES WHICH WAS SET IN 1885.
ANOTHER MOIST SYSTEM AND ASSOCIATED ATMOSPHERIC RIVER WILL REACH
THE AREA THURSDAY AFTERNOON. THIS WILL BRING ANOTHER ROUND OF
WIDESPREAD PRECIPITATION TO THE AREA WITH A SLIGHT CHANCE OF
THUNDERSTORMS FOR THE CENTRAL IDAHO MOUNTAINS. PRECIPITATION
WILL CONTINUE OVERNIGHT INTO FRIDAY. SNOW LEVELS WILL INITIALLY
START AROUND 5500 TO 7000 FEET BEFORE LOWERING AGAIN FRIDAY
NIGHT. SIGNIFICANT SNOW ACCUMULATIONS ARE POSSIBLE FOR THE
HIGHER TERRAIN, WITH 2 TO 4 INCHES POSSIBLE FOR THE MOUNTAIN
VALLEYS.
LONG TERM...SATURDAY THROUGH WEDNESDAY
AS THE UPPER TROUGH MOVES
EAST, LINGERING PRECIPITATION IN THE MOUNTAINS IS EXPECTED SATURDAY
MORNING AND AFTERNOON. PRECIP THAT FALLS IS LIKELY TO BE SNOW WITH
SNOW LEVELS NEAR VALLEY FLOORS, WITH MINIMAL ACCUMULATIONS IN
DWINDLING MOISTURE CONTENT. PRECIPITATION TAPERS OFF COMPLETELY BY
SATURDAY EVENING. AS THE LOW MOVES EAST, THE TROUGH AMPLIFIES AND
BECOMES A RETROGRADING CUT OFF LOW OVER THE CALIFORNIA COAST. THIS
WILL CONVERSELY CAUSE HIGH PRESSURE TO BUILD NORTH OF THE LOW, OVER
OUR AREA, CAUSING A REX BLOCK IN A TEXTBOOK EXAMPLE OF ANTICYCLONIC
WAVE BREAKING. THIS SYNOPTIC PATTERNS MEANS SUNDAY THROUGH THE REST
OF THE LONG TERM WILL BE DRY AND STABLE. STRONG SUBSIDENCE AND
RECENT RAINS WILL SUPPORT THE DEVELOPMENT OF INVERSIONS IN MOST
VALLEYS, CREATING STAGNANT AIR AND LIKELY PERSISTENT FOG AND LOW
STRATUS. TEMPERATURES DURING THIS TIME FRAME ARE UNCERTAIN GIVEN
POOR MODEL RESOLUTION OF THE INVERSION, THOUGH CLIMATOLOGY SUGGESTS
AIR IN THE INVERSION WILL BECOME MUCH COLDER THAN THE AIR ABOVE IT,
ESPECIALLY IF STRATUS STICK AROUND. THIS COULD MEAN FORECAST MORNING
LOWS ARE FEW DEGREES TOO COLD, WHILE AFTERNOON HIGHS COULD BE 5-10
DEGREES TOO WARM.
AVIATION
PRECIPITATION ARRIVING WED/14Z IN SE OREGON, AND
WED/16Z IN SW IDAHO. SNOW LEVELS 6K-8K FEET MSL. GENERALLY VFR-
MVFR IN RAIN, IFR- LIFR IN MTN SNOW. MTNS BECOMING OBSCURED.
AREAS OF LOW LEVEL WIND SHEAR THROUGH MORNING. SURFACE WINDS:
SE-S 5-15 KT. WINDS INCREASING IN AM HOURS TO 15-30 KT WITH
25-45 KT GUSTS. LOCALLY HIGHER GUSTS TO 50-55 KT NEAR NV BORDER
AND IN E-CENTRAL OREGON. WINDS ALOFT AT 10KFT MSL: S-SW 25-40
KT, INCREASING TO 45-60 KT LATE WED AM.
KBOI...CHANCE OF LIGHT RAIN FROM WED/16Z THROUGH LATE WED
NIGHT, BUT SE WIND WILL BE LIMITING FACTOR FOR AMOUNT/INTENSITY.
VFR EXPECTED. SURFACE WINDS: SE-E 5-10 KT TONIGHT, WITH A LOW
LEVEL WIND SHEAR THREAT PRIOR TO THE STRONGER WINDS ALOFT MIXING
DOWN TO THE SURFACE. SURFACE WINDS WILL THEN INCREASE EARLY WED
MORNING HOURS TO SE-E 15- 22 KT WITH GUSTS 25-35 KT. BRIEF
GUSTS TO 40-45 KT POSSIBLE BETWEEN WED/15Z-19Z.
BOI WATCHES/WARNINGS/ADVISORIES
ID...WIND ADVISORY FROM 6 AM THIS MORNING TO 4 PM MST THIS
AFTERNOON IDZ015-029-030.
OR...WIND ADVISORY FROM 6 AM MST /5 AM PST/ THIS MORNING TO 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...JDS
LONG TERM....JM
AVIATION.....JDS
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