054
FXUS65 KBOI 272136
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
236 PM MST SAT DEC 27 2025
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
A TROUGH CONTINUES
TO MOVE EAST OVER MONTANA THIS AFTERNOON. WEST TO NORTHWEST
SURFACE WINDS 10-20 MPH ACROSS THE AREA THIS AFTERNOON EXCEPT
30-40 MPH IN THE MAGIC VALLEY. WINDS EASE AFTER SUNSET WITH
COOL TEMPERATURES TONIGHT. SUNDAY AND MONDAY WILL BE PARTLY
SUNNY AND DRY WITH STAGNANT CONDITIONS DEVELOPING AS UPPER LEVEL
WINDS WEAKEN AND A RIDGE BUILDS INTO THE AREA. TEMPERATURES
WILL BE NEAR NORMAL SUNDAY WITH SLIGHT WARMING ON MONDAY.
LONG TERM...TUESDAY THROUGH SATURDAY
AN UPPER LEVEL RIDGE
WILL BRING DRY AND STABLE CONDITIONS TO THE AREA TUESDAY
THROUGH EARLY THURSDAY. WARMING ALOFT COMBINED WITH COLD AIR
TRAPPED NEAR THE SURFACE WILL CREATE A TEMPERATURE INVERSION. AS
A RESULT, MOST MID TO HIGH ELEVATION SITES WILL SEE
TEMPERATURES 5-10 DEGREES ABOVE NORMAL, WHILE THE LOWEST VALLEYS
WILL BE NEAR TO SLIGHTLY BELOW NORMAL.
A RETURN TO MORE ACTIVE CONDITIONS IS EXPECTED LATE THURSDAY
THROUGH SATURDAY AS AN UPPER LEVEL TROUGH ALONG THE COAST
HELPS TO DIRECT SUBTROPICAL MOISTURE FROM THE SOUTHWEST
NORTHWARD. THE TROUGH IS EXPECTED TO MOVE INLAND FRIDAY OR
SATURDAY. AHEAD OF THE TROUGH, PRECIPITATION CHANCES WILL
INCREASE WITH MILD TEMPERATURES AND SNOW LEVELS AROUND 4000-6000
FEET, POSSIBLY RISING TO AS HIGH AS 7000 FEET IF THE TROUGH IS
DELAYED AND THE FLOW ALOFT BECOMES MORE SOUTHERLY. COOLER AIR
ACCOMPANYING THE TROUGH SHOULD LOWER SNOW LEVELS, POSSIBLY TO
NEAR VALLEY FLOORS BY SATURDAY. IF THE TROUGH CAN DIRECT DEEPER
MOISTURE INTO OUR AREA, AS IS DEPICTED IN A MAJORITY OF
GLOBAL/AI ENSEMBLE MEMBERS, ANOTHER ROUND OF WIDESPREAD
PRECIPITATION WITH MODERATE TOTALS AND MILD TEMPERATURES ARE
EXPECTED. HOWEVER, IF THE TROUGH IS FASTER AS IS FAVORED BY THE
GEFS, THEN LESS PRECIPITATION AND COOLER TEMPERATURES ARE MORE
LIKELY. OVERALL, THE UNCERTAINTY RESULTS IN PRECIPITATION
CHANCES RISING TO AROUND 40-70% BY FRIDAY MORNING, THEN
GRADUALLY DECREASING ON SATURDAY, WITH TEMPERATURES AVERAGING
5-10 DEGREES ABOVE NORMAL.
AVIATION
SCATTERED SNOW SHOWERS BRINGING BRIEF MVFR/IFR
CONDITIONS WILL TAPER OFF THIS EVENING. OTHERWISE, MAINLY VFR,
EXCEPT FOR MVFR/IFR LOW CLOUDS LINGERING INTO SUNDAY MORNING
ACROSS PORTIONS OF NE OREGON AND HIGHER TERRAIN OF SW IDAHO.
MOUNTAINS OBSCURED. SNOW LEVELS ON VALLEY FLOORS. SURFACE WINDS:
W-NW 10-25 KT WITH 20-35 KT GUSTS, STRONGEST IN THE MAGIC
VALLEY. WINDS BECOMING VARIABLE 10 KT OR LESS BY MID EVENING,
EXCEPT W-SW 10-20 KT IN THE MAGIC VALLEY. WINDS ALOFT AT 10KFT
MSL: NW 20-35 KT.
KBOI...VFR. SNOW SHOWERS IN THE VICINITY DECREASING BY LATE
AFTERNOON. SURFACE WINDS: W-NW 10-20 KT WITH GUSTS 20-30 KT,
DECREASING THIS EVENING AND BECOMING LIGHT AND VARIABLE
OVERNIGHT.
AIR STAGNATION
STAGNANT CONDITIONS DEVELOP SUNDAY AS A RIDGE
OF HIGH PRESSURE BEGINS TO BUILD OVER THE AREA. POOR MIXING
HEIGHTS AND A TEMPERATURE INVERSION EXPECTED MONDAY THROUGH
THURSDAY.
BOI WATCHES/WARNINGS/ADVISORIES
ID...AIR STAGNATION ADVISORY FROM 6 PM SUNDAY TO 10 AM MST THURSDAY
IDZ012-014-016-028-033.
OR...AIR STAGNATION ADVISORY FROM 6 PM MST /5 PM PST/ SUNDAY TO 10
AM MST /9 AM PST/ THURSDAY 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....ST
AVIATION.....ST
AIR STAGNATION...KA
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