939
FXUS65 KBOI 170300
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
800 PM MST THU JAN 16 2025
DISCUSSION
CLEAR SKIES THIS EVENING WILL GIVE WAY TO
INCREASING CLOUDS MOVING IN FROM THE NORTH OVERNIGHT. A COLD
FRONT WILL MOVE THROUGH OVERNIGHT, BUT WINDS WON'T REALLY
INCREASE UNTIL FRIDAY. COLDER AIR IS ON THE WAY, AND TEMPS WILL
BE 5 TO 10 DEGREES BELOW NORMAL BY MONDAY. ALL THIS IS HANDLED
WELL BY THE CURRENT FORECAST, AND NO UPDATE IS PLANNED AT THIS
TIME.
AVIATION
MOSTLY VFR UNDER MOSTLY CLEAR SKIES. ISOLATED IFR
DEVELOPING TONIGHT IN MOUNTAIN-VALLEYS WITH CEILINGS/VISIBILITY.
WINDS ALOFT AT 10KFT MSL: W-NW BECOMING NW-N 20-30KT.
KBOI...VFR. WINDS 5 KT OR LESS, BECOMING NW 10-15 WITH GUSTS TO
23 KT AROUND 18Z FRIDAY.
WEEKEND OUTLOOK...VFR. SURFACE WINDS NW 10-20KT SATURDAY, GUSTS
TO 25 KT IN THE SNAKE BASIN EAST OF KMUO SATURDAY AFTERNOON.
LIGHT NORTHWEST WINDS SUNDAY. WINDS ALOFT AT 10KFT MSL NORTH
40-50KT.
AIR STAGNATION
AN AIR STAGNATION ADVISORY WILL REMAIN IN
EFFECT FOR VALLEYS IN SE OREGON AND SW IDAHO THROUGH FRIDAY
MORNING. A COLD FRONT FRIDAY MORNING FOLLOWED BY COLDER AIR
ALOFT WILL IMPROVE MIXING AND END THE INVERSION LATER FRIDAY.
PREV DISCUSSION
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...ONE MORE NIGHT
OF PERSISTENT CONDITIONS BEFORE A COLD FRONT COMES IN FROM THE
NORTH-NORTHWEST FRIDAY MORNING. FRONT WILL BRING SCATTERED
LIGHT SNOW SHOWERS TO NORTHERN AND EASTERN MOUNTAINS WITH ONLY
A DUSTING ACCUMULATION. BEHIND THE FRONT WILL BE INCREASING
NORTHWEST WINDS, STRONGEST IN THE SNAKE BASIN EAST OF MOUNTAIN
HOME WHERE GUSTS WILL REACH 25-30 MPH FRIDAY AFTERNOON. RAPID
COOLING ALOFT WILL END THE INVERSION AND AIR STAGNATION IN THE
VALLEYS BY LATE FRIDAY MORNING. FRIDAY NIGHT WILL BE COLDER
UNDER STRONG NORTHERLY FLOW ALOFT FROM THE NORTHWEST CANADIAN
ARCTIC, BUT WITH MODERATE NORTHWEST SURFACE WINDS CONTINUING,
TEMPERATURES WILL LOWER ONLY 10 DEGREES OR SO FROM TONIGHT'S
LOWS. SATURDAY NIGHT WILL BE COLDER AS WINDS WILL BE LIGHTER,
ESPECIALLY OVER SNOW COVER. LOW TEMPS SATURDAY NIGHT SHOULD BE
THE COLDEST SO FAR THIS WINTER ON THE IDAHO SIDE AS MODIFIED
ARCTIC AIR COMES IN.
LONG TERM...SUNDAY THROUGH THURSDAY...COLD, DRY AIR WILL
CONTINUE, ESPECIALLY IN THE HIGHER EASTERN BASINS ON THE
IDAHO SIDE, CLOSEST TO THE ARCTIC SURGE EAST OF THE CONTINENTAL
DIVIDE. MODEL GUIDANCE SEEMS TO WARM THE LOWER LEVELS TOO
QUICKLY THROUGH WEDNESDAY EVEN AS THE UPPER RIDGE COMES BACK
INLAND. OUR FORECAST IS THEREFORE COLDER THAN MOST MODELS AND
ANOTHER INVERSION EPISODE IS LIKELY NEXT WEEK.
BOI WATCHES/WARNINGS/ADVISORIES
ID...AIR STAGNATION ADVISORY UNTIL 11 AM MST FRIDAY
IDZ011>016-028>030-033.
OR...AIR STAGNATION ADVISORY UNTIL 11 AM MST /10 AM PST/ FRIDAY
ORZ061>064.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.TWITTER.COM/NWSBOISE
DISCUSSION...SP
AVIATION.....SP
AIR STAGNATION...SP
SHORT TERM...LC
LONG TERM....LC
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