426
FXUS65 KBOI 180405
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
905 PM MST TUE DEC 17 2024
DISCUSSION
A WEAK WARM FRONT WILL MOVE OVER THE AREA TONIGHT,
GENERALLY BRINGING LIGHT RAIN TO THE VALLEYS BELOW 4000FT, AND
LIGHT SNOW TO THE MOUNTAINS. PRECIPITATION WILL GENERALLY TAPER
OFF AFTER MIDNIGHT. AFTER THE SYSTEM MOVES NORTHEASTWARD, LOW
CLOUDS AND FOG WILL LINGER IN THE VALLEYS AND OVER THE
MOUNTAINS INTO WEDNESDAY MORNING. A WEAK WAVE WILL MOVE OVER THE
AREA AROUND WEDNESDAY MIDDAY, BRINGING LIGHT SHOWERS TO AREAS
NORTH OF BURNS OR TO BOISE ID. THEN A RIDGE WILL BUILD INTO THE
REGION BRINGING A TEMPERATURE INVERSION ALOFT WITH LOW CLOUDS
AND FOG TRAPPED IN THE VALLEYS FOR THE NEXT SEVERAL DAYS.
TEMPERATURE FORECAST CONFIDENCE IS LOW AT THIS TIME DEPENDING ON
WHERE THE LOW CLOUDS AND FOG SET UP OVER THE AREA. NO UPDATES
TO THE FORECAST.
AVIATION
LIGHT SHOWERS THIS EVENING, EXITING THE AREA AFTER
08Z/WED. MVFR/IFR AND LOCAL LIFR CONDITIONS IN PRECIP. ANOTHER ROUND
OF LIGHT RAIN AND SNOW WILL MOVE ACROSS NORTHERN AREAS 12Z-21Z/WED.
SNOW LEVELS 4000-6000 FT MSL. MOUNTAINS OBSCURED. AREAS OF VALLEY
FOG DEVELOPING OVERNIGHT, INCLUDING NEAR KONO/KBNO. AREAS OF LOW-
LEVEL WIND SHEAR WEDNESDAY MORNING, INCLUDING NEAR KBNO/KMYL.
SURFACE WINDS: SE-SW 5-15 KT, EXCEPT LIGHT AND VARIABLE IN SHELTERED
VALLEYS. WINDS ALOFT AT 10KFT MSL: W-SW 25-45 KT.
KBOI...VFR. LIGHT RAIN SHOWERS POSSIBLE THROUGH 06Z/WED, BUT VFR IS
EXPECTED TO CONTINUE. SUSTAINED SOUTHEAST WINDS SHOULD PREVENT
FOG/LOW STRATUS FORMATION OVERNIGHT. SURFACE WINDS: SE 8-14 KT.
PREV DISCUSSION
SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT...AN AREA OF LIGHT
PRECIPITATION WILL SPREAD BACK OVER THE NORTHERN HALF OF THE
FORECAST AREA THIS EVENING IN ASSOCIATION WITH STATIONARY FRONTAL
ZONE IN ADVANCE OF A WEAK UPPER LEVEL SHORTWAVE MOVING THROUGH
THE AREA ON WEDNESDAY. SNOW LEVELS WILL RISE TO AROUND 5000 FEET
ELEVATION WITH SOME LIGHT SNOW ACCUMULATIONS OF 1 TO 3 INCHES
EXPECTED IN THE MOUNTAINS. AN UPPER LEVEL RIDGE WILL BUILD OVER
THE AREA ON WEDNESDAY NIGHT AND WILL CONTINUE THROUGH THURSDAY
AND INTO THE BEGINNING PORTION OF THE UPCOMING WEEKEND. THE
UPPER LEVEL RIDGE WILL BRING DRY WEATHER BUT WILL ALSO CAUSE A
STRONG TEMPERATURE INVERSION TO FORM IN VALLEY LOCATIONS. THE
STRONG TEMPERATURE INVERSION WILL ALSO SET UP IDEAL CONDITIONS
FOR THE DEVELOPMENT OF FOG IN VALLEYS BELOW ABOUT 3000 FEET
ELEVATION. MOSTLY SUNNY SKIES ARE FAVORED IN THE MOUNTAINS ABOVE
THE FOG LAYER ON THURSDAY.
LONG TERM...FRIDAY THROUGH TUESDAY...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 WEST 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.
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
DISCUSSION...KA
AVIATION.....ST
SHORT TERM...JB
LONG TERM....SP
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page