210
FXUS65 KBOI 292004
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
204 PM MDT SUN MAR 29 2026
KEY MESSAGES
-COLD FRONT WILL BRING A COOLING TREND THROUGH TUESDAY, WITH
GUSTY NORTHWEST WINDS AND CHANCE OF RAIN SHOWERS OVER VALLEYS
AND SNOW SHOWERS OVER MOUNTAINS.
-WEAK SYSTEM WILL CONTINUE PRECIPITATION AND THUNDERSTORM
CHANCES TUESDAY, MAINLY OVER THE SOUTHERN PORTIONS OF THE AREA.
-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.
SHORT TERM /THROUGH TUESDAY NIGHT/
A SHIFT IN THE PATTERN WILL BEGIN MONDAY WITH A COLD FRONT THAT
WILL REACH SOUTHEAST OREGON EARLY MORNING BEFORE TRACKING
THROUGH THE TREASURE VALLEY BY MIDDAY AND EXITING INTO THE MAGIC
VALLEY BY MONDAY EVENING. THIS FRONT WILL BRING A NOTABLE
COOLING TREND, WITH HIGH TEMPERATURES DROPPING INTO THE 50S AND
60S. PRECIPITATION WITH THE FRONTAL PASSAGE WILL BE MOST
CONCENTRATED OVER THE MOUNTAINS OF EAST-CENTRAL OREGON AND WEST-
CENTRAL IDAHO. WHILE LOWER VALLEYS MAY SEE A FEW LIGHT SHOWERS,
MEASURABLE AMOUNTS ARE EXPECTED TO BE MINIMAL. BREEZY NORTHWEST
WINDS WILL DEVELOP BEHIND THE FRONT, WITH GUSTS OF 25 TO 35 MPH
POSSIBLE.
TUESDAY REMAINS UNSETTLED AS A WEAK TRAILING SHORTWAVE TRACKS
ACROSS THE GREAT BASIN. HIGH-RES MODELS REMAIN SPLIT ON THE
TRACK OF THE SHORTWAVE AND ASSOCIATED PRECIPITATION,
PARTICULARLY ALONG MONDAY'S FRONTAL BOUNDARY. THOUGH CONFIDENCE
IS LOW IN THE NORTHERN EXTENT OF THE PRECIPITATION, THIS FEATURE
WILL STEER A BAND OF MOISTURE RESULTING IN A 25 TO 60 PERCENT
CHANCE OF PRECIPITATION ACROSS THE SOUTHERN THIRD OF THE REGION.
WHILE TOTAL LIQUID AMOUNTS WILL GENERALLY RANGE FROM 0.05 TO
0.25 INCHES, THE INTRODUCTION OF COOLER AIR ALOFT AND WEAK
INSTABILITY WILL CREATE AN ENVIRONMENT FAVORABLE FOR A FEW
ISOLATED THUNDERSTORMS DURING THE AFTERNOON AND EVENING HOURS.
SNOW LEVELS WILL RISE BETWEEN THE 5000 TO 7500 FOOT RANGE
TUESDAY AHEAD OF THE NEXT MAJOR SYSTEM, WITH LIGHT ACCUMULATING
SNOW OF 1 TO 2 INCHES POSSIBLE ABOVE 6000 FEET.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
THE WELL ADVERTISED GULF OF ALASKA LOW WILL SWING DOWN ACROSS
THE PACIFIC NW COME WEDNESDAY. THIS LOW WILL BRING WIDESPREAD
PRECIPITATION ACROSS OUR AREA. MOISTURE TRANSPORT IN INCREASING
SOUTHWESTERLY FLOW ALOFT WILL FIRST BRING PRECIPITATION ACROSS
HIGHER TERRAIN; WITH FLOW AT 700MB REACHING 30-50KT, OROGRAPHIC
LIFT WILL BE THE MAIN PLAYER INITIALLY. THE STRONGEST FORCING
(AND THEREFORE THE PERIOD OF HEAVIEST/MOST WIDESPREAD
PRECIPITATION) WILL COME WEDNESDAY NIGHT THROUGH THURSDAY, AS
THE MAIN TROUGH AND COLD FRONT MOVES ACROSS OUR AREA. WITH WEAK
ELEVATED INSTABILITY AND FORCING ALONG THE FRONT, CONVECTIVE
ENHANCEMENT WILL ALLOW FOR LOCALLY HEAVIER PRECIPITATION RATES
AND A SLIGHT CHANCE OF THUNDER. SNOW LEVELS DURING THIS PERIOD
WILL BE BETWEEN 6-4.5 KFT MSL.
COME THURSDAY AFTERNOON, THE COLD FRONT WILL BE EAST OF OUR
AREA WITH THE CORE OF THE 500MB LOW NEARLY OVERHEAD
(TEMPERATURES AT 500MB WILL BE NEAR -32 DEGREES CELSIUS, WITHIN
THE 10TH PERCENTILE OF CLIMATOLOGY). GUSTY WEST-NORTHWEST POST
FRONTAL WINDS WILL ALSO SET IN THURSDAY. WHILE CLOUD COVER WILL
LIKELY REDUCE DIURNAL HEATING, THESE COLD TEMPS ALOFT WHEN
COMBINED WITH DIURNAL HEATING WILL ALLOW FOR WEAK INSTABILITY TO
BUILD IN. THIS WILL ALLOW FOR PRECIPITATION TO TAKE ON A MORE
SHOWERY NATURE, WITH RAIN, SNOW/GRAUPEL SHOWERS, AND PERHAPS
EVEN SOME THUNDERSTORMS. SNOW LEVELS BEHIND THE FRONT WILL DROP
TO 3-4KFT MSL, WHICH WILL ALLOW FOR MOUNTAIN VALLEYS TO
ACCUMULATE A COUPLE INCHES OF SNOW (50-70% CHANCE). OVER THE
COURSE OF WEDNESDAY/THURSDAY, LIQUID PRECIPITATION TOTALS OF
0.30-0.75 INCHES ARE FORECAST IN LOWER ELEVATIONS, WITH 0.75-1.5
INCHES OF LIQUID OVER THE MOUNTAINS. ABOVE 6500 FEET, THERE IS
A 70+ PERCENT CHANCE OF RECEIVING OVER A FOOT OF SNOW.
AS THE TROUGH MOVES EAST OUT OF OUR AREA THROUGH FRIDAY AND
RIDGING BEGINS TO BUILD BACK, PRECIPITATION CHANCES WILL TAPER
OFF AND A WARMING TREND WILL SET IN THROUGH SUNDAY.
AVIATION /18Z SUNDAY THROUGH MONDAY/
ISSUED 1208 AM MDT SUN MAR 29 2026
VFR TODAY, A COLD FRONT MON/AM WILL BRING SCATTERED RAIN/SNOW
SHOWERS MAINLY NORTH OF A LINE FROM KBNO-KONO-KSNT. MVFR/IFR
CONDITIONS IN RAIN/SNOW SHOWERS WITH MTN OBSCURATION. SNOW
LEVELS: 7-9KFT MSL, LOWERING TO 2-4KFT MSL BEHIND THE FRONT.
SURFACE WINDS: SW-W 5-15 KT. GUSTS 20-35 KT ACROSS SE OREGON
AND HIGHER TERRAIN SW IDAHO THROUGH 30/03Z. BECOMING W-NW 5-15
KT WITH LOCALIZED GUSTS TO 20 KT MON/AM. WINDS ALOFT AT 10KFT
MSL: W-SW 20-35 KT.
KBOI...VFR. SURFACE WINDS: GENERALLY LIGHT AND VARIABLE, WITH
PERIODS OF W-SW WINDS UP TO 10KT POSSIBLE THIS AFTERNOON.
BECOMING W-NW 5-10 KT OVERNIGHT TONIGHT.
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
SHORT TERM...JDS
LONG TERM....NF
AVIATION.....NF
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