944
FXUS65 KBOI 262127
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
227 PM MST FRI DEC 26 2025
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
A BRIEF LULL
CONTINUES IN PRECIPITATION THIS AFTERNOON FROM BOISE, ID TO
ROME OR WITH MOSTLY CLEAR SKIES THROUGH LATE THIS AFTERNOON.
CLOUDS ARE INCREASING IN CENTRAL AND EASTERN OR AHEAD OF THE
NEXT COLD FRONT WITH SNOW DEVELOPING AT BURNS OR AS OF 220PM
MST. THE NEXT COLD FRONT MOVES THROUGH LATE THIS EVENING INTO
SATURDAY MORNING WITH SCATTERED SNOW SHOWERS AND SNOW LEVELS
FALLING TO THE VALLEY FLOORS. PRECIPITATION AMOUNTS WILL BE
LIGHT WITH THIS SYSTEM, WITH MINIMAL SNOW ACCUMULATIONS BELOW
5000 FEET. ABOVE 5000 FEET, SNOW ACCUMULATIONS OF 4 TO 7 INCHES
POSSIBLE WITH LOCALLY HIGHER AMOUNTS ON THE PEAKS WHERE A WINTER
WEATHER ADVISORY REMAINS IN EFFECT. SNOW AMOUNTS WILL BE HIGHLY
VARIABLE DUE TO THE SHOWERY NATURE OF THE PRECIPITATION.
HEAVIER BANDS OF SNOW POSSIBLE OVER THE WEST CENTRAL ID
MOUNTAINS EARLY SATURDAY MORNING INTO THE AFTERNOON, BUT THE
BEST DYNAMICS FOR HEAVY SNOW SHOWERS WILL GENERALLY BE OVER THE
CENTRAL ID PANHANDLE MOUNTAINS AND NORTHEAST INTO WESTERN MT
WHERE THE COLDEST AIR ALOFT IS. HIGH TEMPERATURES SATURDAY WILL
BE AROUND 10 DEGREES COOLER THAN TODAY. BREEZY WEST-NORTHWEST
WINDS FOLLOW THE FRONT WITH GUSTS OF 25-40 MPH DURING THE
AFTERNOON SATURDAY. SUNDAY WILL BE MOSTLY SUNNY AND DRY WITH
STAGNANT CONDITIONS DEVELOPING AS UPPER LEVEL WINDS WEAKEN.
LONG TERM...MONDAY THROUGH FRIDAY
DRY CONDITIONS THROUGHOUT
THE COMING WEEK. RIDGING WILL BUILD IN ABOVE A LOW OVER THE
PACIFIC, THIS BLOCKING PATTERN (REX BLOCK) WILL ALLOW PROLONGED
HIGH PRESSURE OVER THE REGION. THIS SET-UP WILL RESULT IN
STRONG VALLEY INVERSIONS WITH UPPER-LEVEL SUBSIDENCE AND THE LOW
SUN ANGLE OF THIS TIME OF YEAR. WITH PLENTY OF SURFACE MOISTURE
TO WORK WITH, AND A FAVORABLE PATTERN, FOG AND LOW STRATUS WILL
BE A CONCERN EACH DAY AS WELL AS DECREASING AIR QUALITY BELOW
THE INVERSION. DAY TIME HIGHS MAY BE A LITTLE OVER DONE, WITH
THE POTENTIAL OF A COLD POOL AND REDUCED SURFACE HEATING UNDER
POTENTIAL FOG/LOW STRATUS. CONVERSELY, MORNING LOW TEMPS MAY BE
A BIT UNDER DONE UNDER THE SAME CONDITIONS, WITH CLOUD COVER
REDUCING DIURNAL COOLING.
THE FIRST SIGNS OF A PATTERN CHANGE COME LATE NEXT WEEK. CLUSTER
ANALYSIS IS SHOWING INCREASING AGREEMENT AMONG GRAND ENSEMBLE
MEMBERS; WITH THE FAVORED SOLUTION BEING A TROUGH DIGGING DOWN
FROM THE GULF OF ALASKA LATE THURSDAY INTO EARLY FRIDAY.
INCREASED MIXING WITH THE TROUGH WILL WORK TO LIFT THE INVERSION
IN THE LATE WEEK AS WELL. PRECIPITATION CHANCES WILL INCREASE
THURSDAY AFTERNOON THROUGH FRIDAY AREA-WIDE AS THE TROUGH MOVES
ASHORE.
AVIATION
VFR. SHOWERS INCREASING W-E THIS AFTERNOON ALONG AND
BEHIND OF A COLD FRONT. VFR/MVFR IN RAIN SHOWERS, MVFR/LIFR IN
SNOW SHOWERS. MOUNTAINS OBSCURED IN PRECIP. SNOW LEVELS: 3.5-5.5
KFT MSL, LOWERING TO VALLEY FLOORS BEHIND THE COLD FRONT.
SURFACE WINDS: S-W 5-15 KT WITH GUSTS UP TO 30 KT OUTSIDE OF THE
SNAKE RIVER PLAIN, BECOMING W-NW 10-20KT WITH GUSTS TO 20-30 KT
BEHIND A COLD FRONT. WINDS ALOFT AT 10KFT MSL: SW 20-40 KT.
KBOI...VFR. SHOWERS RETURNING OVER THE FOOTHILLS THIS AFTERNOON.
SCATTERED SNOW FLURRIES THROUGHOUT THE DAY SATURDAY MAY RESULT
IN BRIEF MVFR, ALTHOUGH CHANCES ARE 20% AND LESS THROUGHOUT
THE DAY. NO ACCUMULATION EXPECTED. SURFACE WIND: VARIABLE
BECOMING S-SE 7-12 KT THIS AFTERNOON. SWITCHING TO W-NW 10-15 KT
WITH GUSTS UP TO 25 KT AFTER SAT/08Z.
WEEKEND OUTLOOK...SNOW LEVELS LOWERING TO VALLEY FLOORS SATURDAY.
SCATTERED TO NUMEROUS SNOW SHOWERS SATURDAY, WITH MVFR-LIFR
CONDITIONS IN PRECIP. MTNS OBSCURED. SHOWERS ENDING SATURDAY
EVENING. VFR, COLD, DRY SUNDAY. SURFACE WINDS: W TO NW 15-25 KT
SATURDAY WITH 25-35 KT GUSTS. LIGHT WINDS SUNDAY.
AIR STAGNATION
STAGNANT CONDITIONS DEVELOP SUNDAY AS A RIDGE
OF HIGH PRESSURE BEGINS TO BUILD OVER THE AREA. POOR MIXING
HEIGHTS EXPECTED MONDAY THROUGH THURSDAY. A TEMPERATURE
INVERSION WILL STRENGTHEN MONDAY THROUGH WEDNESDAY OF NEXT WEEK
AS THE RIDGE MOVES OVERHEAD WITH WARMER TEMPERATURES ALOFT.
BOI WATCHES/WARNINGS/ADVISORIES
ID...WINTER WEATHER ADVISORY UNTIL 5 AM MST SATURDAY IDZ011-013.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
SHORT TERM...KA
LONG TERM....NF
AVIATION.....NF
AIR STAGNATION...KA
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