931
FXUS65 KBOI 310017
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
617 PM MDT MON MAR 30 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
-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.
-THE MOST IMPACTFUL SYSTEM ARRIVES LATE WEDNESDAY, BRINGING
GUSTY WINDS AND HEAVY MOUNTAIN SNOW INTO THURSDAY. HEAVY WET
SNOW IS EXPECTED ABOVE 6000 FEET, POTENTIALLY RESULTING IN
SLUSHY OR SNOW-COVERED CONDITIONS ON HIGHWAY 55, HIGHWAY 21 AND
US 95 THURSDAY MORNING.
-DRY WEATHER AND ABOVE NORMAL TEMPERATURES RETURN FOR THE
WEEKEND.
SHORT TERM /THROUGH WEDNESDAY NIGHT/
ISSUED 209 PM MDT MON MAR 30 2026
A WEAK COLD FRONT CONTINUES TO MOVE SOUTHWARD ACROSS THE
FORECAST AREA THIS AFTERNOON AND EVENING. THIS WILL MAINTAIN
SCATTERED SHOWERS ACROSS MUCH OF THE AREA. LIGHT SNOW
ACCUMULATION HAS ALREADY OCCURRED ABOVE 6000 FEET, AND FURTHER
ACCUMULATION IS POSSIBLE IN MOUNTAIN VALLEYS THIS EVENING.
HOWEVER, THIS WILL BE LIMITED TO COLDER SURFACES, WHILE SITES IN
VALLEY COUNTY ABOVE 6000 TO 6500 FEET MSL WILL PICK UP 1 TO 2
INCHES. BREEZY NORTHWEST WINDS OF 15 TO 25 MPH WITH GUSTS TO 30
MPH WILL CONTINUE INTO THE EVENING AS THE FRONT REACHES THE
NEVADA BORDER. A SHOWER OR TWO IS POSSIBLE (10 PERCENT CHANCE)
FOR THE TREASURE VALLEY, BUT LITTLE TO NO MEASURABLE
PRECIPITATION IS EXPECTED.
A SECOND WAVE WILL PUSH INTO THE REGION ON TUESDAY, BRINGING
ANOTHER ROUND OF SHOWERS. MOST HIGH-RES GUIDANCE HAS COME INTO
AGREEMENT REGARDING A PERIOD OF LIGHT TO MODERATE PRECIPITATION
AHEAD OF THE TROUGH TUESDAY MORNING. THIS WILL BE FOCUSED ALONG
A WARM FRONT SHIFTING NORTHWARD ACROSS THE AREA. SHOWERS AND
THUNDERSTORMS ARE THEN EXPECTED TO DEVELOP IN THE UNSTABLE AIR
ON THE BACK END OF THE TROUGH TUESDAY AFTERNOON AND EVENING.
MOST AREAS HAVE A 60 TO 80 PERCENT CHANCE FOR MEASURABLE
PRECIPITATION, WITH A BROAD AREA OF 0.05 TO 0.15 INCH AMOUNTS
THROUGH TUESDAY EVENING. LOCALLY HIGHER AMOUNTS ARE POSSIBLE,
ESPECIALLY ALONG THE FRONTAL BOUNDARY. SOUTHWEST FLOW AHEAD OF
THIS WAVE WILL RAISE SNOW LEVELS TO 6500 TO 7500 FEET.
THE MAIN UPPER LEVEL LOW WILL MOVE INTO THE PACIFIC NORTHWEST
ON WEDNESDAY. THIS IS WHEN PRECIPITATION BECOMES WIDESPREAD
ACROSS THE REGION, ESPECIALLY WEDNESDAY NIGHT. GUSTY SOUTHWEST
WINDS AHEAD OF THE SYSTEM WILL REACH 20 TO 30 MPH WITH GUSTS OF
35 TO 45 MPH ACROSS SOUTHEAST OREGON AND THE HIGHER TERRAIN OF
SOUTHWEST IDAHO, MOSTLY SOUTH OF THE SNAKE PLAIN. THE MILD AND
MOIST AIRMASS ALONG WITH THE FAVORABLE UPPER LEVEL DYNAMICS,
SUPPORTS A CHANCE OF THUNDERSTORMS. SNOW LEVELS WILL HOLD AROUND
6500 FEET MSL DURING THE DAY, DROPPING TO BETWEEN 4500 TO 6000
FEET OVERNIGHT AS COLDER AIR MOVES IN ALOFT BEHIND THE COLD
FRONT. THIS IS WHEN THE HEAVIEST SNOW (8 TO 16 INCHES) WILL
OCCUR ABOVE 6500 FEET, IMPACTING HIGHER ROADWAYS ACROSS BANNER
SUMMIT, BIG CREEK SUMMIT, AND WARM LAKE SUMMIT. MOUNTAIN VALLEYS
WILL SEE ACCUMULATIONS (3 TO 6 INCHES) AS RAIN CHANGES TO SNOW
WEDNESDAY NIGHT AND EARLY THURSDAY MORNING WITH THE FRONTAL
PASSAGE. PARTS OF STATE HIGHWAY 55 AND US 95 COULD BECOME SLUSHY
OR SNOW COVERED THURSDAY MORNING. WIDESPREAD PRECIPITATION
AMOUNTS OF 0.20 TO 0.50 INCHES ARE EXPECTED ACROSS LOWER
ELEVATIONS, WITH 0.50 TO 1.00 INCH IN THE MOUNTAINS THROUGH
WEDNESDAY NIGHT.
LONG TERM /THURSDAY THROUGH MONDAY/
ISSUED 209 PM MDT MON MAR 30 2026
WIDESPREAD PRECIPITATION WILL CONTINUE THURSDAY AS THE UPPER
LEVEL LOW CONTINUES TO INFRINGE UPON OUR AREA. BY THURSDAY
AFTERNOON, THIS LOW WILL BE CENTERED OVER E-OREGON/SW-IDAHO.
WITH THE COLD CORE OVER OUR AREA, WEAK INSTABILITY WILL BE ABLE
TO BUILD IN THROUGH DIURNAL HEADING (ALTHOUGH CLOUD COVER WILL
HELP REDUCE THE AMOUNT OF DESTABILIZATION). AS A RESULT,
PRECIPITATION WILL TAKE ON A SHOWERY NATURE WITH RAIN,
SNOW/GRAUPEL, AND PERHAPS EVEN A THUNDERSTORM THURSDAY
AFTERNOON. WITH THE COLD FRONT EAST OF OUR AREA COME THURSDAY
AFTERNOON, WINDY WEST/NORTHWEST POST-FRONTAL WINDS WILL ALSO SET
IN. THE STRONGEST WINDS WILL BE IN THE TYPICAL LOCATIONS, WITH
GUSTS TO 35-50 MPH IN THE SNAKE PLAIN EAST OF MOUNTAIN HOME,
CAMAS PRAIRIE, AND ALONG RIDGE TOPS. ELSEWHERE, WINDS WILL GUSTS
TO 20-35MPH (BARRING SHELTERED MOUNTAIN VALLEYS).
AS THE SYSTEM EXITS OUR AREA TO THE EAST THROUGH FRIDAY,
PRECIPITATION CHANCES WILL BEGIN TO TAPER OFF WITH SCATTERED
SHOWERS CONTINUING OVER HIGHER TERRAIN. COME SATURDAY, DRY
CONDITIONS WILL PREVAIL WITH A WARMING TREND SETTING IN AS
RIDGING BEGINS TO BUILD BACK IN BEHIND THE TROUGH. BY SUNDAY,
TEMPERATURES WILL BE UP TO 5-10 DEGREES ABOVE NORMAL. ENSEMBLE
AND DETERMINISTIC GUIDANCE HINT AT A SHORTWAVE GRAZING OUR AREA
TO THE NORTH COME MONDAY AFTERNOON, LEADING TO A SLIGHT CHANCE
OF SHOWERS OVER THE TERRAIN IN OUR NORTHERN ZONES.
AVIATION /00Z TUESDAY THROUGH WEDNESDAY/
ISSUED 552 PM MDT MON MAR 30 2026
SHOWERS INCREASING TONIGHT INTO TUESDAY IN ALL AREAS ALONG A
FRONTAL BOUNDARY. MAINLY LOW VFR OR MVFR IN RAIN, WITH MVFR/IFR
IN THE MOUNTAINS. MOUNTAINS OBSCURED. SNOW LEVELS: 4-6KFT MSL
ACROSS THE NORTH, 6-7KFT MSL CENTRAL AND SOUTH. ISOLATED
THUNDERSTORMS DEVELOPING TUESDAY AFTERNOON WITH GUSTS UP TO 35
KT AND SMALL HAIL POSSIBLE. SURFACE WINDS: W-NW 5-15 KT,
BECOMING VARIABLE LESS THAN 10 KT OVERNIGHT. WINDS TUESDAY SW-NW
5-15 KT, WITH GUSTS 20-30 KT OVER THE HIGHER TERRAIN AND SW OF
THE SNAKE BASIN. WINDS ALOFT AT 10KFT MSL: W-SW 20-35 KT.
KBOI...MAINLY VFR. A 30% CHANCE OF RAIN SHOWERS THIS EVENING.
STEADY RAIN DEVELOPING OVERNIGHT INTO TUESDAY MORNING, BRINGING
A 30% CHANCE OF MVFR CEILINGS. A 15% CHANCE OF A THUNDERSTORM
AFTER TUE/20Z. SURFACE WINDS: NW 5-15 KT, BECOMING SE LESS THAN
10 KT OVERNIGHT.
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.....ST
SHORT TERM...JDS
LONG TERM....NF
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