331
FXUS65 KBOI 111616
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
916 AM MST TUE NOV 11 2025
DISCUSSION
CONTINUED DRY AND MILD THROUGH THURSDAY MORNING
UNDER HIGH PRESSURE ALOFT. A WEAK SURFACE-BASED INVERSION WILL
CONTINUE WITH AFTERNOON TEMPS IN THE LOWER VALLEYS SLIGHTLY
COOLER THAN AT HIGHER ELEVATIONS. ON THURSDAY THE HIGH PRESSURE
ALOFT WILL SHIFT EAST, AND MOIST, SOUTHWESTERLY FLOW WILL COME
INTO EASTERN OR AHEAD OF AN APPROACHING PACIFIC COLD FRONT AND
UPPER TROUGH. SHOWERS WILL BEGIN IN EASTERN OR THURSDAY
AFTERNOON, THEN CWA-WIDE THURSDAY NIGHT AS THE COLD FRONT
MOVES THROUGH. THE FRONTAL PASSAGE, AND COOLING ALOFT LATER
ON, SHOULD MIX-OUT THE INVERSION.
AVIATION
VFR UNDER MID/HIGH-LEVEL CLOUDS. SURFACE WINDS:
VARIABLE UP TO 10 KT. WINDS ALOFT AT 10KFT MSL: W 10-25 KT.
KBOI...VFR. SE UP TO 5 KT THIS MORNING, BECOMING LIGHT AND
VARIABLE THIS AFTERNOON.
AIR STAGNATION
WEAK SURFACE-BASED INVERSION AND LIMITED
MIXING WILL CONTINUE THROUGH EARLY THURSDAY AS HIGH PRESSURE
ALOFT AND SUBSIDENCE KEEP MIXING HEIGHTS NEAR OR SLIGHTLY BELOW
2 KFT AGL IN VALLEYS. MIXING SHOULD DEEPEN LATER THURSDAY AS A
PACIFIC SURFACE COLD FRONT AND UPPER TROUGH APPROACH THURSDAY,
REMOVING THE INVERSION THURSDAY NIGHT.
PREV DISCUSSION
SHORT TERM...TODAY THROUGH THURSDAY NIGHT...MILD AND DRY
CONDITIONS CONTINUE TODAY AND THROUGH MUCH OF THE SHORT TERM
AS A RIDGE PERSISTS. AN INVERSION REMAINS OVER MANY LOWER
VALLEYS, WITH MIXING HEIGHTS NEAR TO LESS THAN 2 KFT AGL. TEMPS
TODAY THROUGH THURSDAY WILL BE 10-15 DEGREES ABOVE NORMAL, WITH
THE WARMEST DAY BEING WEDNESDAY. AS SOUTHWESTERLY FLOW INCREASES
AHEAD OF THE TROUGH LATER IN THE WEEK, WINDS INCREASE WEDNESDAY
AND THURSDAY. A 15 TO 30 PERCENT CHANCE OF SHOWERS IS EXPECTED
ACROSS SOUTHEAST OREGON AND THE CENTRAL IDAHO MOUNTAINS LATE
WEDNESDAY NIGHT AS THE TROUGH MOVES INLAND. SNOW LEVELS WILL BE
8000 TO 9000 FEET MSL AS THE PRECIPITATION BEGINS. CLOUDS WILL
INCREASE WEDNESDAY AS A HIGH-AMPLITUDE TROUGH STRENGTHENS OVER
THE WEST COAST. ISOLATED SHOWERS WILL DEVELOP LATE THURSDAY,
WITH HIGHER CONFIDENCE EARLY FRIDAY AS THE TROUGH AND COLD FRONT
MOVE THROUGH THE REGION.
LONG TERM...FRIDAY THROUGH TUESDAY...A STRONG TROUGH AXIS MOVES
OVERHEAD FRIDAY, WITH A COLD FRONT BRINGING PRECIPITATION AND
COLDER TEMPERATURES. IN LOWER ELEVATIONS THERE WILL BE A 40-60%
CHANCE OF PRECIPITATION LATE THURSDAY THROUGH FRIDAY MORNING.
AT HIGHER ELEVATIONS IT WILL BE 80-90%. SIMILARLY, THE FORECAST
RAINFALL TOTALS ARE UP TO 0.15 INCH FOR LOWER ELEVATIONS, AND
UP TO 0.50 INCH FOR HIGHER. TEMPS WILL COOL TO JUST A FEW
DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR, AND SNOW LEVELS DROP
TO 5-6 KFT MSL BY FRIDAY AFTERNOON. SNOW ON RIDGES AND HIGH
ELEVATION PASSES WILL BE 1-3 INCHES. AFTER SUNDAY DETERMINISTIC
MODELS DEPICT A TROUGH DEEPENING IN THE REGION, CONSISTENT WITH
ENSEMBLE CLUSTERS. MOST CLUSTERS SHOW THE TROUGH DEEPENING OVER
THE AREA TUESDAY MORNING, BUT ONE CLUSTER AND THE GFS
DETERMINISTIC SHOW ANOTHER CLOSED LOW OFF THE SOCAL COAST
FORMING. ALL THIS TO SAY: WHILE GENERALLY UNSETTLED AND COLDER
WEATHER IS IN STORE MONDAY/TUESDAY, SIGNIFICANT UNCERTAINTY
REMAINS IN THE DETAILS AS OF THE LATEST RUNS.
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
AIR STAGNATION...LC/JM
SHORT TERM...JM
LONG TERM....JM
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