578
FXUS65 KBOI 301201
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
601 AM MDT MON MAR 30 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
-COOLER WITH PERIODS OF VALLEY RAIN AND MOUNTAIN SNOW THROUGH
TUESDAY. BREEZY NORTHWEST WINDS IN THE DAYTIME WILL GUST UP TO
30 MPH AND AFTERNOON THUNDERSTORMS ARE POSSIBLE ON TUESDAY.
-STRONG GULF OF ALASKA LOW WILL BRING WIDESPREAD PRECIPITATION
AND A SLIGHT CHANCE FOR THUNDERSTORMS WEDNESDAY AND THURSDAY,
WITH RAIN IN THE VALLEYS AND MODERATE TO HEAVY SNOWFALL OVER
MOUNTAINS.
-DRY WEATHER AND ABOVE NORMAL TEMPERATURES RETURN FOR THE
WEEKEND.
SHORT TERM /THROUGH WEDNESDAY NIGHT/
ISSUED 408 AM MDT MON MAR 30 2026
COOLER CONDITIONS WILL SETUP TODAY INTO TUESDAY AS A SERIES OF
UPPER TROUGHS TRACK ACROSS THE REGION. THE FIRST SYSTEM WILL
PASS TO THE NORTH, PUSHING A COLD FRONT INTO THE AREA LATER
TODAY. A BAND OF RAIN AND SNOW WILL DEVELOP OVER BAKER COUNTY
AND THE W-CENTRAL IDAHO MTNS LATER THIS MORNING AND BE SLOW TO
MOVE SOUTH THROUGH THE DAY. LIGHT SNOW ACCUMULATION IS POSSIBLE
IN MTN VALLEYS THROUGH THE MORNING, BUT WILL BE LIMITED TO
COLDER SURFACES WHILE SITES IN VALLEY COUNTY ABOVE 6-6.5KFT MSL
WILL PICK UP 1 TO 3 INCHES. THE FRONT WILL USHER IN BREEZY
NORTHWEST WINDS AS IT REACHES THE NV BORDER BY THIS EVENING.
IT'S NOT A PARTICULARLY STRONG FRONT AND PRECIPITATION COVERAGE
WILL DECREASE AS IT EXTENDS SOUTH. WIND GUSTS WILL TOP OUT
AROUND 30 MPH BEHIND THE FRONT.
A SECOND WAVE WILL PUSH INTO THE REGION ON TUESDAY, BRINGING
ANOTHER ROUND OF SHOWERS. CURRENT MODEL TIMING WOULD SUPPORT A
PERIOD OF LIGHT-MODERATE PRECIP AHEAD OF THE TROUGH MONDAY
NIGHT INTO TUESDAY, WITH SHOWERS AND THUNDERSTORMS DEVELOPING IN
THE UNSTABLE AIR ON THE BACKEND OF THE TROUGH TUESDAY AFTERNOON
AND EVENING. MOST AREAS SEE A 60-80% CHANCE FOR MEASURABLE
PRECIPITATION WITH A BROAD AREA OF 0.05-0.15" AMOUNTS THROUGH
TUESDAY EVENING. LOCALLY HIGHER AMOUNTS ARE LIKELY BUT WILL BE
HARD TO PIN DOWN GIVEN THE SHOWERY NATURE OF THE PRECIPITATION
LATER IN THE DAY. THE SOUTHWEST FLOW AHEAD OF THIS WAVE WILL
RAISE SNOW LEVELS TO 6.5-7.5KFT ON TUESDAY.
THE MAIN LOW, AND MOST IMPACTFUL WEATHER SYSTEM THIS WEEK, WILL
MOVE INTO THE PAC NW ON WEDNESDAY. PRECIPITATION BECOMES
WIDESPREAD ACROSS THE REGION BY AFTERNOON, AND CONTINUES INTO
WEDNESDAY NIGHT. GUSTY SOUTHWEST WINDS AHEAD OF THE LOW WILL
REACH 20-30 MPH WITH GUSTS OF 35 TO 45 MPH ACROSS SE OREGON AND
HIGHER TERRAIN OF SW IDAHO (MOSTLY SOUTH OF THE SNAKE PLAIN).
THE MILD/MOIST AIR MASS AND FAVORABLE UPPER LEVEL CONDITIONS
WILL SUPPORT A CHANCE OF THUNDERSTORMS DURING THE DAY. SNOW
LEVELS WILL HOLD BETWEEN 6-7KFT MSL DURING THE DAY, DROPPING TO
BETWEEN 4500-6KFT OVERNIGHT AS COLDER AIR MOVES IN ALOFT. THE
HEAVIER SNOW DURING THIS PERIOD WILL BE ABOVE 6-6.5KFT,
IMPACTING HIGHER ROADWAYS ACROSS BANNER SUMMIT, BIG CREEK
SUMMIT, AND WARM LAKE SUMMIT. MOUNTAIN VALLEYS WILL SEE
ACCUMULATIONS AS RAIN CHANGES TO SNOW WED NIGHT. WIDESPREAD
PRECIPITATION AMOUNTS OF 0.2-0.5" ARE EXPECTED ACROSS LOWER
ELEVATIONS WITH 0.50-1.00" IN THE MOUNTAINS THROUGH WEDNESDAY
NIGHT.
LONG TERM /THURSDAY THROUGH MONDAY/
ISSUED 408 AM MDT MON MAR 30 2026
THE AREA WILL REMAIN UNDER THE JET EXIT REGION OF THE POTENT
UPPER LOW DIGGING ACROSS THE NORTHWEST ON THURSDAY. THE 500 MB
LOW CORE IS EXPECTED TO CENTER OVER OUR CWA AS IT DIGS OUT EAST.
STRONG COLD FRONTAL PASSAGE ASSOCIATED WITH THIS LOW WILL
SUSTAIN WIDESPREAD VALLEY RAIN, MOUNTAIN SNOW, AND GUSTY WEST-
NORTHWEST WINDS THURSDAY. WHILE DENSE CLOUD COVER WILL LIKELY
REDUCE DIURNAL HEATING, THE COLD TEMPS ALOFT FROM THE LOW CORE
WILL ALLOW FOR WEAK INSTABILITY TO BUILD IN. THIS WILL ALLOW FOR
PRECIPITATION TO TAKE ON A MORE SHOWERY/CONVECTIVE NATURE, WITH
RAIN, SNOW/GRAUPEL SHOWERS, AND EVEN SOME THUNDERSTORMS
THURSDAY AFTERNOON. SNOW LEVELS BEHIND THE FRONT WILL DROP TO
3-4KFT MSL, WHICH WILL ALLOW FOR MOUNTAIN VALLEYS TO ACCUMULATE
A COUPLE INCHES OF SNOW AND ELEVATIONS ABOVE 6500 FT TO
ACCUMULATE UP TO A FOOT BY LATE THURSDAY.
BY FRIDAY, THE AREA WILL BE UNDER THE BACKEND OF THE LOW STEERING
OUT EAST AND BE UNDER NORTHWEST FLOW. A 30-50% CHANCE OF
PRECIPITATION WILL CONTINUE OVER THE MOUNTAINS THROUGH FRIDAY
AFTERNOON. OTHERWISE, RIDGING FROM A PACIFIC HIGH WILL BUILD BACK IN
FRIDAY THROUGH THE WEEKEND, RETURNING DRY CONDITIONS AND A WARMING
TREND WITH TEMPERATURES CLIMBING 5-10 DEGREES ABOVE NORMAL. LONG-
TERM GUIDANCE SUGGESTS ANOTHER UPPER LOW STEERING INLAND FROM THE
GULF OF ALASKA EARLY NEXT WEEK, BUT WITH CONSIDERABLE GUIDANCE
UNCERTAINTY OVER ITS PATTERN BEHAVIOR AND ARRIVAL. FOR NOW, MOUNTAIN
AREAS MAY SEE A 20-30% CHANCE OF PRECIP ON MONDAY.
AVIATION /12Z MONDAY THROUGH TUESDAY/
ISSUED 551 AM MDT MON MAR 30 2026
GENERALLY VFR. A COLD FRONT WILL BRING A RAIN/SNOW BAND WITH
MVFR-IFR CONDITIONS OVER THE EAST-CENTRAL OR AND WEST- CENTRAL
ID MOUNTAINS THIS MORNING. MVFR-IFR CONDITIONS WILL PERSIST OVER
MOUNTAIN AREAS THROUGH THE AFTERNOON. MOUNTAINS WILL BE
OBSCURED IN PRECIP. WIDESPREAD RAIN SHOWERS WILL RETURN OVER
SOUTHEAST OR AND WEST-CENTRAL ID MOUNTAINS MONDAY LATE NIGHT
AFTER 05Z. SURFACE WINDS W-NW LESS THAN 10 KT EARLY MORNING,
INCREASING TO 10-20 KT AFTER 16Z. WINDS ALOFT AT 10KFT MSL: W-SW
20-35 KT.
KBOI...VFR. INCREASING MID-LEVEL CLOUDS WITH A STRAY SHOWER
POSSIBLE IN THE MORNING AFTER 14Z. SURFACE WINDS VARIABLE UNDER
10 KT THROUGH THE MORNING, BECOMING NW 10-15 KT IN THE
AFTERNOON AFTER 18Z.
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
AVIATION.....JY
SHORT TERM...DG
LONG TERM....JY
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