126
FXUS65 KBOI 221618
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
918 AM MST MON DEC 22 2025
DISCUSSION
SUNDAY'S WARM FRONT WENT AS FAR NORTH AS OUR
NORTHERN CWA THEN SHIFTED SOUTHWARD AGAIN DURING THE NIGHT,
BUT NOT AS FAR SOUTH AS MODELS PREDICTED. THIS MORNING THE
FRONT AND LIGHT RAIN WERE STILL DRAPED SW-NE ACROSS OUR SOUTHERN
ZONES. THE ATMOSPHERIC RIVER (AR) ALIGNED WITH THE FRONT HAS
BROADENED AND WEAKENED BUT SHOULD BECOME STRONGER AND NARROWER
LATER TODAY AND TONIGHT AS THE FRONT TURNS NORTHWARD AGAIN AS
A WARM FRONT. THIS NORTHWARD SHIFT WILL OCCUR IN RESPONSE TO A
DEEPENING UPPER TROUGH OFF THE COAST THAT WILL CAUSE UPPER
LEVEL WINDS TO BECOME MORE SOUTHERLY. THE REVIVED WARM FRONT
AND INCREASED RAIN WILL MOVE TO OUR NORTHERN CWA EARLY TUESDAY
MORNING, THEN CONTINUE NORTHWARD INTO WA AND NORTHERN ID LATER
TUESDAY. OUR CWA WILL THEN BE IN THE "WARM SECTOR" SOUTH OF THE
WARM FRONT AND EAST OF A COLD FRONT STILL OFF THE COAST, WITH
BOTH TUESDAY AND WEDNESDAY WARMER AND DRIER THAN CURRENTLY.
NO WHITE CHRISTMAS THIS YEAR. HOWEVER...LONGEST RANGE MODELS,
IN PARTICULAR ECMWF, ARE PREDICTING A PATTERN CHANGE AT THE
END OF DECEMBER TO COLDER BUT STILL MOIST NORTHWESTERLY FLOW
ALOFT FOR A POSSIBLY SNOWY END TO THE YEAR. MORE ON THAT IN
LATER DISCUSSIONS. FOR NOW THE CURRENT FORECAST IS ON TRACK
THE NEXT SEVERAL DAYS, WITH THE MOST IMPACTFUL WEATHER BEING
GUSTY SOUTHWEST WINDS IN SOUTHERN ZONES WEDNESDAY. NO UPDATES.
AVIATION
PRECIPITATION AND LOW CLOUDS CONCENTRATING MAINLY
OVER SW ID AND KONO THIS MORNING, EXPECTED TO TAPER OFF IN THE
EARLY AFTERNOON. MVFR-LIFR IN STRATUS/FOG REMAIN OVER MOST SITES
OF SW/W-CENTRAL ID THIS MORNING, WITH IMPROVEMENT LATER THIS
AFTERNOON AND EARLY EVENING. SNOW LEVELS 6-8 KFT MSL. AREAS OF
LLWS. SURFACE WINDS: SE-SW 5-15 KT, AND SW GUSTS 20-30 KT OVER
LOWER MAGIC VALLEY. WINDS ALOFT AT 10KFT MSL: W-SW 30-50KT.
KBOI...DENSE OVC CLOUD COVERAGE AND RAIN OVER NEXT SEVERAL
HOURS, CONTINUING VFR/MVFR CONDITIONS. IFR-LIFR FOG/LOW CLOUDS
HANGING OVER FOOTHILLS AND VICINITY, BUT EXPECTED TO MOSTLY
CLEAR UP LATER THROUGH THE EARLY AFTERNOON. SURFACE WINDS SE
AROUND 5-10 KT.
PREV DISCUSSION
SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...AN UPPER LEVEL
TROUGH REMAINS OVER HAIDA GWAII THIS MORNING, GIVING US MOIST
SOUTHWEST FLOW ALOFT. A BAND OF MODERATE PRECIPITATION EXTENDS
FROM LAKEVIEW OR TO ONTARIO OR TO MCCALL ID. THIS BAND WILL
SLOWLY MOVE SOUTH BY MID MORNING AND WEAKEN OVER THE MAGIC
VALLEY BY THIS AFTERNOON WITH PARTIAL CLEARING OVER MUCH OF THE
AREA. TEMPERATURES REMAIN MILD TODAY, WITH SNOW LEVELS AROUND
5000 FEET NEAR BAKER/BURNS OR TO 8000 FEET NEAR TWIN FALLS.
LATE MONDAY NIGHT INTO TUESDAY MORNING, THIS BAND OF
PRECIPITATION WILL MOVE NORTHWARD ACROSS THE AREA AND EXTEND
FROM BAKER CITY OR OR MCCALL ID, WITH DRY AND WARM CONDITIONS TO
THE SOUTH TUESDAY AFTERNOON. TEMPERATURES IN THE SNAKE PLAIN
WILL BE IN THE MID TO UPPER 50S TUESDAY AFTERNOON, OR AROUND
15-20 DEGREES ABOVE NORMAL. SOUTHEAST WINDS INCREASE ON
WEDNESDAY MORNING, WITH MILD OVERNIGHT LOWS. ON WEDNESDAY THE
UPPER LEVEL LOW BEGINS TO DIG SOUTH ALONG THE WEST COAST,
ALLOWING FOR MILD SOUTHERLY FLOW TO INCREASE OVER THE REGION.
WINDY CONDITIONS EXPECTED FOR MUCH OF WEDNESDAY IN THE WARM
SECTOR OF THE SYSTEM. PRECIPITATION INCREASES LATE IN THE
AFTERNOON, WITH RAIN SHOWERS OVER MUCH OF THE AREA AND SNOW
LEVELS AROUND 7500-8000 FEET. BOISE AND MCCALL WILL BE NEAR
RECORD HIGHS BOTH TUESDAY AND WEDNESDAY AFTERNOONS!
LONG TERM...THURSDAY THROUGH MONDAY...THE DEEP UPPER LOW THAT
HAS CONTINUED TO STEER MOISTURE THROUGH THE REGION WILL BEGIN
TO MOVE INLAND THURSDAY. THIS WILL LEAD TO CONTINUED
PRECIPITATION BUT WITH GUSTY RIDGETOP WINDS AND LOWER SNOW
LEVELS THROUGH SATURDAY. PRECIPITATION IS LIKELY FOR MUCH OF THE
AREA AS SNOW LEVELS THURSDAY DROP FROM 5-6 KFT MSL TO 3-4 KFT
MSL BY FRIDAY EVENING. WHILE THIS BEGINS TO HINT AT WINTRY
PRECIPITATION FOR LOWER ELEVATIONS BY SATURDAY, SNOW LEVELS DROP
TO VALLEY FLOORS AS THE UPPER LOW AND PRECIPITATION MOVE
EAST/TAPER OFF. THUS, LOWER ELEVATIONS WILL SEE MOSTLY RAIN WITH
TOTALS OF LESS THAN 0.25". LIQUID EQUIVALENT OR RAIN TOTALS IN
MOUNTAINS WILL BE CLOSER TO 1". MOUNTAIN TOWNS WILL SEE 1-5" AS
SNOW LEVELS DROP, WHILE RIDGES SEE 6-10". TEMPERATURES THURSDAY
OF 10-15 DEGREES ABOVE NORMAL COOL DOWN TO 5 DEGREES ABOVE
NORMAL BY SATURDAY AS THE CENTER OF THE LOW MOVES OVERHEAD.
SATURDAY NIGHT THROUGH MONDAY, TEMPS HOLD STEADY AT JUST ABOVE
NORMAL FOR THIS TIME OF YEAR AS MOST OF THE GUIDANCE SUGGESTS A
RIDGE BUILDING OVERHEAD. THE RIDGE AND INCREASING HEIGHTS ALOFT
WITH TEMPS HOLDING STEADY SHOWS SOME EARLY SIGNS OF A POTENTIAL
INVERSION. IF ANY INVERSION DOES FORM, IT SEEMS LIKE IT MAY
SHORTLIVED AS THE EXTENDED FORECAST SHOWS A RETURN TO UNSETTLED
WEATHER NEXT WEEK.
BOI WATCHES/WARNINGS/ADVISORIES
ID...NONE.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
DISCUSSION...LC
AVIATION.....JY
SHORT TERM...KA
LONG TERM....JM
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