652
FXUS65 KBOI 211102
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
402 AM MST WED JAN 21 2026
SHORT TERM...TODAY THROUGH FRIDAY NIGHT
LOW CLOUDS AND FOG
REMAIN IN THE VALLEYS GENERALLY BELOW 5000 FEET THIS MORNING AND
WILL PERSIST OVER THE NEXT SEVERAL DAYS. THE CLOUDS MAY PRODUCE
FLURRIES AT TIMES. IN THE MOUNTAINS, MOSTLY CLEAR SKIES
EXPECTED WITH MILD TEMPERATURES DURING THE DAY AND COLD
TEMPERATURES AT NIGHT. TEMPERATURES WILL REMAIN WELL BELOW
GUIDANCE IN THE SNAKE BASIN AND HAVE USED PERSISTENCE IN THE
FORECAST AS THE NBM AND MOST OF THE HIGH RESOLUTION GUIDANCE
CANNOT RESOLVE THE SNAKE BASIN COLD POOL. CLOUDS SHOULD PERSIST
THROUGH FRIDAY BELOW 5000 FEET.
LONG TERM...SATURDAY THROUGH WEDNESDAY
DRY CONDITIONS CONTINUE
AND PERSISTENCE WAS USED AS THE ENSEMBLE AND NBM GUIDANCE
REMAINS USELESS IN THE SNAKE BASIN. COOLER AIR ALOFT WILL BEGIN
TO MOVE INTO THE AREA ON SATURDAY WHICH MAY HELP TO CLEAN OUT
THE LOW CLOUDS AND FOG, AND ACTUALLY WARM UP TEMPERATURES IN THE
VALLEYS, ALTHOUGH FORECAST CONFIDENCE IS LOW. A RIDGE BUILDS
INTO THE AREA AGAIN BY TUESDAY, WITH WARMER AIR ALOFT AND A
TEMPERATURE INVERSION STRENGTHENING AGAIN. WITH PERSISTENCE
USED, TEMPERATURES IN THE VALLEYS REMAIN BELOW NORMAL WITH ABOVE
NORMAL TEMPERATURES OVER THE MOUNTAINS.
AVIATION
LOW CLOUDS AND FOG IN VALLEYS BELOW 5-6KFT MSL.
SURFACE WINDS VARIABLE 10KT OR LESS.
KBOI...MVFR-IFR STRATUS. SURFACE WINDS VARIABLE LESS THAN 10KT.
AIR STAGNATION
STAGNANT CONDITIONS REMAIN IN THE VALLEYS OF
SOUTHEAST OREGON AND SOUTHWEST IDAHO. MIXING HEIGHTS WILL REMAIN
BELOW 2000 FEET AGL THROUGH AT LEAST THURSDAY NIGHT, SO THE AIR
STAGNATION ADVISORY HAS BEEN EXTENDED UNTIL 5 AM MST FRIDAY.
COOLING ALOFT LATER FRIDAY WILL WEAKEN THE INVERSION AND MAY
PROVIDE TEMPORARY IMPROVEMENT, BUT THE INVERSION IS EXPECTED TO
STRENGTHEN AGAIN THROUGH THE WEEKEND.
BOI WATCHES/WARNINGS/ADVISORIES
ID...AIR STAGNATION ADVISORY UNTIL 5 AM MST FRIDAY
IDZ011>014-016-028-033.
OR...AIR STAGNATION ADVISORY UNTIL 5 AM MST /4 AM PST/ FRIDAY
ORZ061>064.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
SHORT TERM...KA
LONG TERM....KA
AVIATION.....KA
AIR STAGNATION...KA
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