664
FXUS65 KBOI 180957
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
255 AM MST WED DEC 18 2024
SHORT TERM...TODAY THROUGH FRIDAY NIGHT
A WEAK PACIFIC WARM
FRONT PASSED THROUGH OUR CWA TUESDAY EVENING WITH LIGHT RAIN
AND SNOW IN CENTRAL AND NORTHERN AREAS. A PACIFIC COLD FRONT
WILL PASS THROUGH LATER TODAY WITH LIGHT RAIN AND SNOW AGAIN
IN NORTHERN AREAS. TOTAL NEW SNOWFALL SHOULD BE LESS THAN ONE
INCH. LIGHT TO MODERATE SURFACE WINDS AND INCREASED WESTERLY
FLOW ALOFT UNDER THE ASSOCIATED UPPER TROUGH WILL KEEP FOG OUT
OF THE VALLEYS TODAY EXCEPT NEAR WEISER/ID AND ONTARIO/OR.
TEMPERATURES WILL BE MILD AGAIN TODAY. AFTER THE UPPER TROUGH
EXITS EAST THIS EVENING AN UPPER RIDGE WILL COME IN FROM THE
PACIFIC AND LAST THROUGH SATURDAY MORNING. THE RIDGE WILL BRING
IN WARMER AIR ALOFT RESULTING IN AN INVERSION IN THE VALLEYS
BELOW. AREAS OF FOG AND LOW CLOUDS WILL DEVELOP THURSDAY AND
FRIDAY ESPECIALLY IN THE LOWER TREASURE VALLEY. DAYTIME
TEMPERATURES WILL BE COLDER BELOW ABOUT 3500 FEET MSL. NO
PRECIPITATION THURSDAY THROUGH FRIDAY NIGHT.
LONG TERM...SATURDAY THROUGH WEDNESDAY
THERE CONTINUES TO BE
EXCELLENT AGREEMENT BETWEEN MODELS IN THE LONG TERM PERIOD. WE
EXPECT A WEAK RIDGE TO PASS OVER THE AREA FRIDAY, ENHANCING THE
INVERSION THAT WILL SET UP IN THE SHORT TERM. SATURDAY, A STRONG
TROUGH WILL APPROACH FROM THE WEST, INDUCING STRONGER WINDS
THROUGHOUT MOST OF THE REGION. THIS WILL HELP DEVELOP SOUTHEAST
WINDS IN THE UPPER TREASURE VALLEY AND SHOULD PUSH THE
INVERSION WESTWARD INTO THE LOWER TREASURE VALLEY, WHERE IT
WILL LIKELY LINGER UNTIL LATE IN THE DAY. THIS SHOULD KEEP LOW
CLOUDS AND/OR FOG GOING ROUGHLY WEST OF CALDWELL FOR MOST OF
SATURDAY. AN INITIAL SHORTWAVE TROUGH IS FORECAST TO MOVE
RAPIDLY ACROSS THE AREA SATURDAY EVENING, BRINGING A QUICK
BURST OF PRECIPITATION. SNOW LEVELS SHOULD RANGE FROM 7000 FT
MSL IN THE SOUTH TO 4500 FT MSL IN BAKER COUNTY. AFTER A RIDGE
MOVES ACROSS SUNDAY, ANOTHER SHORTWAVE TROUGH WILL BRING
ADDITIONAL PRECIPITATION SUNDAY NIGHT INTO MONDAY MORNING, WITH
SIMILAR SNOW LEVELS. POPS ARE HIGHEST FOR THIS SYSTEM SUNDAY
NIGHT, RANGING FROM 80% IN THE NORTHERN MOUNTAINS TO 30% IN THE
SOUTH. YET ANOTHER DRY RIDGE WILL RACE OVER THE AREA MONDAY INTO
MONDAY NIGHT, WITH STRONG SW FLOW ALOFT MOVING IN TUESDAY AHEAD
OF ANOTHER TROUGH.
AVIATION
LIGHT SHOWERS TODAY, EXITING THE AREA AFTER 06Z.
MVFR/IFR AND LOCAL LIFR CONDITIONS IN PRECIP. ALSO VLIFR IN
LOW CLOUDS/FOG FROM KEUL TO KONO THIS MORNING. THAT SHOULD
IMPROVE THIS AFTERNOON BEFORE BUILDING BACK IN THIS EVENING.
MOUNTAINS OBSCURED. SNOW LEVELS 4500-6000 FT MSL. AREAS OF
VALLEY FOG ARE EXPECTED WED MORNING, ESPECIALLY KONO/KEUL.
SURFACE WINDS: SE-SW 5-15 KT. WINDS ALOFT AT 10KFT MSL:
W 20-40 KT.
KBOI...VFR. LIGHT RAIN SHOWERS MAY BRIEFLY RETURN THIS EVENING,
BUT VFR IS EXPECTED TO CONTINUE. IFR/MVFR FOG IS POSSIBLE (20%
CHANCE) TONIGHT, BUT IS MUCH MORE LIKELY TO THE WEST. SURFACE
WINDS: LESS THAN 5 KT THIS AFTERNOON, BECOMING SE 4-12 KT AFTER
18/00Z.
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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