900
FXUS65 KBOI 121624
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
924 AM MST WED NOV 12 2025
DISCUSSION
CONTINUED MILD AND DRY THROUGH MOST OF THURSDAY IN
IDAHO, BUT COOLING IN OREGON THURSDAY AS A WEAKENING PACIFIC COLD
FRONT COMES INLAND. THE SUPPORTING UPPER TROUGH OFF THE COAST HAS
FORMED A CLOSED LOW NEAR 39N/139W. THE LOW IS HEADED FOR SOUTHERN
CALIFORNIA WHILE THE NORTHERN PORTION MOVES RAPIDLY EASTWARD ALONG
NEAR THE CANADIAN BORDER. THE TROUGH WILL BE WEAKEST AS IT PASSES
THROUGH OUR AREA, AND THE COLD FRONT WILL ALSO WEAKEN THURSDAY
NIGHT BUT STILL BE ABLE TO SCOUR THE WEAK INVERSION. PRE-FRONTAL
SOUTH-SOUTHWEST WINDS WILL REACH 25-35 MPH IN GUSTS IN SOUTHERN
AREAS THURSDAY AFTERNOON. CURRENT FORECAST IS ON TRACK. NO UPDATE.
AVIATION
VFR UNDER HIGH CLOUDS. ISOLATED LIGHT RAIN/VIRGA
SHOWERS THIS AFTERNOON. SURFACE WINDS: VARIABLE UP TO 10 KT.
WINDS ALOFT AT 10KFT MSL: SW 10-20 KT.
KBOI...VFR. SURFACE WINDS: SE 5-10 KT.
PREV DISCUSSION
SHORT TERM...TODAY THROUGH FRIDAY NIGHT...MILD AND DRY WEATHER
THROUGH THURSDAY MORNING AS AN UPPER RIDGE AND INVERTED
CONDITIONS KEEP WINDS LIGHT AND TEMPERATURES VERY WARM FOR THIS
TIME OF YEAR. HIGH TEMPS WEDNESDAY AND THURSDAY ARE AS HIGH AS
15-20 DEGREES ABOVE NORMAL, PEAKING THURSDAY WITH SOME SNAKE
PLAIN LOCATIONS POTENTIALLY SEEING JUST UNDER 70 DEGREES. A
PERSISTENT WEAK INVERSION WILL MAKE FOR HAZY CONDITIONS, WITH
SOME MORNING MIST POSSIBLE.
OFF THE WEST COAST, A LOW PRESSURE TROUGH AMPLIFIES, LEADING TO
INCREASING CLOUDS THROUGH THE FIRST HALF OF THE SHORT TERM. BY
THURSDAY MORNING, THE LEADING EDGE OF THE MOISTURE SUPPORTS A
SLIGHT CHANCE OF PRECIPITATION WITH SNOW LEVELS STILL HIGH AT
8-9 KFT MSL. THE LEADING EDGE WILL ALSO BRING GUSTY WINDS ON
THURSDAY, WITH GUSTS 25-35 MPH IN SE OREGON AND SW IDAHO
HIGHLANDS AND RIDGES. THIS, AND A COLD FRONT THURSDAY NIGHT/
FRIDAY MORNING WITH INCREASED PRECIPITATION CHANCES, WILL SCOUR
OUT THE INVERSION. SOME UNCERTAINTY IS APPARENT AMONGST MODELS
AS THE FRONT MOVES THROUGH, BUT THE CHANCE OF PRECIPITATION FOR
HIGHER NORTHERN TERRAIN IS STILL 80-90% AND 30-50% FOR LOWER
ELEVATIONS. THE UNCERTAINTY HAS LED TO A SLIGHTLY HIGHER SNOW
LEVEL FORECAST BEHIND THE COLD FRONT, WITH SNOW LEVELS ON
FRIDAY NOW 6-8 KFT MSL AND TEMPS 5 DEGREES ABOVE NORMAL,
DROPPING EXPECTED SNOWFALL ON RIDGES SIGNIFICANTLY. THE
EXPECTED RAINFALL OR LIQUID EQUIVALENT FOR MOUNTAINS IS STILL
IN THE REALM OF 0.30-0.50 INCH, AND LESS THAN 0.10 INCH FOR
LOWER ELEVATIONS. PRECIPITATION CONTINUES THROUGH FRIDAY, WITH
THE BEST CHANCES IN THE MORNING. THE HIGH-AMPLITUDE TROUGH
BECOMES A CLOSED LOW OVER SOCAL BY THE END OF SATURDAY,
DEAMPLIFYING THE JET STREAM OVER THE REGION AND INDICATING
A BRIEF BREAK IN PCPN IN THE LONG TERM.
LONG TERM...SATURDAY THROUGH WEDNESDAY...WITH THE REGION IN
THE DEFORMATION ZONE OF A CLOSED LOW OFF THE SOCAL COAST AND
THE JET STREAM TO THE NORTH ON SATURDAY, ONLY A SLIGHT CHANCE
OF PRECIPITATION FOR BAKER AND VALLEY COUNTIES EXISTS ON
SATURDAY. MODEL RUN-TO-RUN VARIABILITY HAS BEEN SIGNIFICANT IN
THE TRACK OF THE CLOSED LOW SUNDAY ONWARDS (AS IS USUAL WITH
CLOSED LOWS, MUCH TO MY (AND MY FORECAST'S) DISMAY. THE CLOSED
LOW AMONGST ENSEMBLE MEANS SEEMS TO TRACK NORTHEASTWARD, JUST
CLIPPING THE AREA SUNDAY NIGHT WITH PACIFIC MOISTURE. WHAT WOULD
HAVE BEEN A FAIRLY SHORTLIVED SYSTEM, WILL BE LENGTHENED BY A
NEW TROUGH DEVELOPING ALMOST IMMEDIATELY BEHIND THE CLOSED LOW.
THE VAST MAJORITY OF MODELS DEPICT THIS TROUGH, LEADING TO HIGH
CONFIDENCE IN A WETTER AND COOLER START TO MONDAY AS ITS COLD
FRONT MOVES THROUGH. THIS WILL DROP TEMPS DOWN TO NEAR NORMAL
MONDAY THROUGH WEDNESDAY WITH SNOW LEVELS AT 4-5 KFT MSL. THIS
WOULD GIVE RIDGELINES AND PASSES THE COUPLE OF INCHES OF SNOW
THEY NOW MISS OUT ON IN THE THURSDAY SYSTEM, POSSIBLY EVEN
IMPACTING HIGH ELEVATION TOWNS SUCH AS MCCALL WITH SOME SNOW
ACCUMULATION.
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...LC
AVIATION.....NF
SHORT TERM...JM
LONG TERM....JM
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