900
FXUS65 KBOI 220359
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
859 PM MST SAT FEB 21 2026
DISCUSSION
AN UPPER LEVEL RIDGE CONTINUES TO BUILD OVER THE
INTERMOUNTAIN WEST. THIS PATTERN HAS INITIATED A NOTICEABLE
WARMING TREND ACROSS SOUTHEAST OREGON AND SOUTHWEST IDAHO.
CURRENT SATELLITE IMAGERY SHOWS MID AND HIGH LEVEL CLOUDS
STREAMING OVERHEAD, WHICH WILL ACT TO KEEP OVERNIGHT
TEMPERATURES SEVERAL DEGREES WARMER THAN PREVIOUS NIGHTS. EXPECT
DRY CONDITIONS TO PERSIST THROUGH SUNDAY MORNING AS THE REGION
SITS WITHIN THE WARM SECTOR OF AN APPROACHING PACIFIC SYSTEM.
SOUTHERLY FLOW ALOFT WILL STRENGTHEN TONIGHT AND SUNDAY, LEADING
TO BREEZY CONDITIONS. SURFACE WINDS WILL BE STRONGEST THROUGH
THE SNAKE RIVER PLAIN AND ACROSS THE HIGHER TERRAIN OF SOUTHEAST
OREGON, WHERE GUSTS OF 20 TO 35 MPH ARE EXPECTED BY SUNDAY
AFTERNOON. NO UPDATES NEEDED AT THIS TIME.
AVIATION
VFR WITH MID/HIGH CEILINGS. AREAS OF LLWS NEAR
KONO/KBNO OVERNIGHT INTO SUNDAY MORNING. SURFACE WINDS: E-S 5-15 KT,
WITH LOCALIZED GUSTS TO 28 KT OVERNIGHT IN THE SNAKE PLAIN.
INCREASING TO 10-20 KT WITH GUSTS 20-30 KT IN THE W SNAKE PLAIN AND
NEAR KBKE BEGINNING LATE SUNDAY AM. WINDS ALOFT AT 10KFT MSL: SW 15-
30 KT.
KBOI...VFR. SURFACE WINDS: SE 10-15 KT. GUSTS TO 23-28 KT BEGINNING
LATE MORNING.
PREV DISCUSSION
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT...CONTINUED BREEZY, DRY,
AND WARMER THROUGH MONDAY EVENING BEFORE MOISTURE FROM THE PACIFIC
SUBTROPICS FLOWS INTO OUR CWA MONDAY NIGHT, AHEAD OF A COLD FRONT
TUESDAY. EAST OR SOUTHEAST WINDS DUE TO LOW PRESSURE ALONG THE
COAST WILL CONTINUE 15 TO 30 MPH TONIGHT, WITH STRONGEST GUSTS
(NEAR 40 MPH AROUND MOUNTAIN HOME,ID). SPEEDS WILL DECREASE TO
10-20 MPH SUNDAY THROUGH MONDAY BUT STILL FROM THE EAST OR
SOUTHEAST. TONIGHT SHOULD BE 4-7 DEGREES WARMER THAN LAST NIGHT,
AND HIGHS SUNDAY 8 TO 12 DEGREES WARMER THAN TODAY. LOWS SUNDAY
NIGHT ABOUT 5 DEGREES WARMER THAN TONIGHT, AND HIGHS MONDAY
ABOUT 2 DEGREES WARMER THAN SUNDAY AS CLOUDS INCREASE. LIGHT
RAIN AND SNOW WILL BEGIN MONDAY EVENING IN NORTHERN AND WESTERN
MOUNTAINS (SNOW LEVEL 5200-6200 FEET), THEN OVER MOST OF OUR
CWA LATER MONDAY NIGHT, EXCEPT DRY NEAR THE OR/NV BORDER AND
SOUTH OF THE SNAKE RIVER IN ID UNTIL TUESDAY MORNING.
LONG TERM...TUESDAY THROUGH SATURDAY...A PACIFIC TROUGH WILL
RESIDE OFF THE WEST COAST ON TUESDAY AT THE SAME TIME AS A
BROAD, ARCTIC TROUGH OVER CANADA CONTINUES TO PULSE INTO THE
NORTHERN U.S. AHEAD OF THE PACIFIC TROUGH, A NOTABLE SUBTROPICAL
MOISTURE PLUME OVER W OREGON, WASHINGTON, AND THE IDAHO
PANHANDLE WILL BE NUDGED SOUTHWARD BY THE CANADIAN TROUGH
TUESDAY MORNING. THIS WILL ALLOW THE MOISTURE TO SPAN ACROSS THE
REST OF OREGON AND INTO SW IDAHO, AND INCREASE PRECIPITATION
CHANCES TO 75-95% AREA-WIDE. MID-LEVEL SOUTHWESTERLY WINDS WILL
BECOME MODERATELY STRONG (40-60 KT) AND SUPPORT ENHANCED UPSLOPE
FLOW/PRECIPITATION FOR THE IDAHO TERRAIN, WHILE SIMULTANEOUSLY
REDUCING PRECIP AMOUNTS IN SHADOWED VALLEY LOCATIONS. DUE TO
THE SUBTROPICAL ORIGIN OF THE PLUME, SNOW LEVELS WILL BE BEGIN
RELATIVELY HIGH AT APPROXIMATELY 5500 FEET MSL TO THE NORTH AND
7500 FEET TO THE SOUTH. WITH THE HIGHER SNOW LEVELS, HEAVIER
SNOWFALL WILL BE LIMITED TO THE HIGHER TERRAIN DURING THIS TIME.
IN ADDITION TO PRECIP, WINDS AT THE SURFACE WILL BECOME GUSTY
ON TUESDAY, PARTICULARLY ACROSS SOUTHEAST OREGON AND
CENTRAL/SOUTH-CENTRAL IDAHO.
A SHORTWAVE TROUGH ALONG THE BACK SIDE OF THE PARENT CANADIAN
LOW WILL THEN BRING A COLD FRONT THROUGH THE FORECAST AREA LATE
TUESDAY INTO WEDNESDAY, QUICKLY LOWERING SNOW LEVELS TO AROUND
3000 FEET FOR THE NORTH AND 4500 FEET ACROSS THE SOUTH.
LINGERING PRECIPITATION IN THE AREA WILL BEGIN TO TAPER OFF
FROM NORTHWEST TO SOUTHEAST THROUGHOUT WEDNESDAY AS THE FRONT
USHERS IN DRIER AIR. THEREFORE, THE TAPERING PRECIP WILL KEEP
ANY SNOWFALL ACCUMULATIONS LIGHT ACROSS THE LOWER AND MID-
ELEVATIONS. GUSTY WINDS ARE FORECAST TO CONTINUE ON WEDNESDAY
BEHIND THE COLD FRONT, ESPECIALLY ACROSS SOUTH-CENTRAL IDAHO.
WHILE MORNING TEMPERATURES ON WEDNESDAY WILL BE NOTICEABLY
COOLER THAN TUESDAY MORNING, WEDNESDAY DAYTIME TEMPERATURES
WILL ONLY BE LOWERED A FEW DEGREES.
AS THE PRECIPITATION EXITS THE AREA LATE WEDNESDAY, DRIER WEST
TO NORTHWEST FLOW ALOFT WILL BECOME DOMINANT THURSDAY THROUGH
SATURDAY. TEMPERATURES WILL WARM AS THE BULK OF THE COLDER AIR
SHIFTS TOWARD THE EAST. A CHANCE OF PRECIPITATION (15-30%) WILL
REMAIN ACROSS WEST-CENTRAL IDAHO AS WAVES OF MOISTURE PROPAGATE
ALONG THE BACK SIDE OF THE CANADIAN TROUGH.
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...JDS
AVIATION.....NF
SHORT TERM...LC
LONG TERM....SH
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