764
FXUS65 KBOI 191022
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
322 AM MST THU DEC 19 2024
SHORT TERM...TODAY THROUGH SATURDAY NIGHT
A LOW-LEVEL
INVERSION WILL RE-DEVELOP TODAY THROUGH SATURDAY MORNING,
BUT YESTERDAY'S COMPLETE MIXING HAS DELAYED THE RETURN OF
FOG AND LOW CLOUDS. MODELS INSIST IT WILL HAPPEN THOUGH,
IF NOT TODAY, THEN FRIDAY, AS WINDS ALOFT BECOME MUCH
LIGHTER AND COLD AIR COLLECTS IN THE LOWER VALLEYS. WE
DECREASED THE EXTENT OF FOG/STRATUS TODAY FROM YESTERDAY'S
FORECAST BUT MORE SHOULD OCCUR FRIDAY, ESPECIALLY IN THE
LOWER TREASURE VALLEY. TODAY WILL STILL BE MUCH COOLER
THAN YESTERDAY IN THE VALLEYS. NO PCPN UNTIL SATURDAY
AFTERNOON WHEN THE NEXT PACIFIC TROUGH COMES INLAND.
LONG TERM...SUNDAY THROUGH THURSDAY
A SERIES OF TROUGHS
WILL ARRIVE THROUGH THE EXTENDED FORECAST PERIOD, WITH EACH
NEW TROUGH SEEMINGLY STRONGER THAN THE LAST. THE TIMING FOR
THESE TROUGHS WILL BE LATE SUNDAY INTO MONDAY, TUESDAY INTO
EARLY WEDNESDAY, AND THE NEXT ON THURSDAY. WITH EACH TROUGH,
PRECIPITATION CHANCES WILL BE HIGH (70-90%) FOR THE FORECAST
AREA. WINDS WILL BECOME BREEZY BOTH AHEAD AND BEHIND EACH
TROUGH PASSAGE/COLD FRONT. SNOW LEVELS WILL RANGE ROUGHLY
3000-5000 FT MSL FOR THE NORTHERN ZONES, AND 4500-7000 FT
MSL FOR THE SOUTHERN ZONES CLOSER TO THE NV BORDER THROUGH
TUESDAY. MUCH COLDER AIR WILL ARRIVE BY WED/THU, WITH SNOW
LEVELS LOWERING TO 2500-4500 FT MSL FOR THE ENTIRE AREA.
SNOW TOTALS FOR HIGH ELEVATIONS, AND RAIN TOTALS FOR LOWER
ELEVATIONS, MAY BECOME SIGNIFICANT FROM THIS MULTI-DAY EVENT.
AVIATION
GENERALLY VFR. PATCHY IFR/LIFR FOG IN BASINS
AND VALLEYS AT/NEAR KBNO KONO KEUL KMYL THIS MORNING.
SOME IMPROVEMENT TO VFR THIS AFTERNOON, THEN FOG
RETURNING TONIGHT. SURFACE WINDS: VARIABLE LESS THAN
10 KT. WINDS ALOFT AT 10KFT MSL: W TO SW 10-25 KT.
KBOI...VFR. PATCHY FOG W-NW OF THE AIRPORT THIS MORNING,
WITH A LOW CHANCE (10%) THAT IT WILL REACH KBOI. THEN,
A HIGHER CHANCE (30%) OF FOG AT KBOI BEGINNING LATE TONIGHT.
SURFACE WINDS: SE UP TO 10 KT.
WEEKEND OUTLOOK...AREAS OF VALLEY FOG FRIDAY MORNING,
OTHERWISE VFR. PRECIPITATION SPREADING FROM W TO E BY
SATURDAY AFTERNOON THROUGH EARLY SUNDAY, THEN RETURNING
AGAIN SUNDAY NIGHT. MVFR TO LIFR IN PRECIPITATION EXPECTED,
WITH SNOW LEVELS ROUGHLY 3500-5000 FT MSL DURING PRECIP.
MOUNTAINS OBSCURED. SURFACE WINDS: GENERALLY SW-SE 5-15
KT EACH DAY. LOW LEVEL WIND SHEAR POSSIBLE SAT NIGHT.
BOI WATCHES/WARNINGS/ADVISORIES
ID...NONE.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.TWITTER.COM/NWSBOISE
SHORT TERM...LC
LONG TERM....SH
AVIATION.....SH
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