609
FXUS65 KBOI 272007
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
207 PM MDT FRI MAR 27 2026
KEY MESSAGES
- DRY WEATHER WITH WARMING TEMPERATURES THROUGH SUNDAY.
- COOLER MONDAY AND TUESDAY WITH GUSTY WINDS AND AN INCREASED
CHANCE OF SHOWERS AND HIGH MOUNTAIN SNOW.
- GULF OF AK LOW WILL BRING WIDESPREAD PRECIPITATION WEDNESDAY
AND THURSDAY. ACCUMULATING SNOW IS POSSIBLE DOWN TO MOUNTAIN
VALLEY FLOORS WITH HEAVY SNOW POSSIBLE ABOVE 6500 FEET.
SHORT TERM /THROUGH SUNDAY NIGHT/
UPPER LEVEL RIDGING WILL REMAIN THE DOMINANT FEATURE ACROSS
SOUTHEAST OREGON AND SOUTHWEST IDAHO THROUGH THE WEEKEND. THIS
RIDGE WILL MAINTAIN DRY CONDITIONS AND PROMOTE A SIGNIFICANT
WARMING TREND, WITH TEMPERATURES REACHING 10 TO 15 DEGREES ABOVE
SEASONAL NORMALS. WITH THE RIDGE KEEPING THE ATMOSPHERE DRY AT
THE LOWER LEVELS, A WEAK IMPULSE MOVING ACROSS CENTRAL NEVADA
WILL BRING AN INCREASE IN HIGH CLOUD COVER ON SATURDAY. DESPITE
THE FILTERED SUNSHINE, AFTERNOON HIGHS WILL CONTINUE TO CLIMB,
GENERALLY WARMING 3 TO 8 DEGREES OVER FRIDAY'S VALUES. LOW LEVEL
EASTERLY WINDS WILL PERSIST, PARTICULARLY ACROSS THE SNAKE
RIVER PLAIN, THOUGH SPEEDS ARE EXPECTED TO REMAIN BELOW ANY
ADVISORY THRESHOLDS.
BY SUNDAY, THE RIDGE BEGINS TO FLATTEN IN RESPONSE TO AN
APPROACHING UPPER LEVEL TROUGH FROM THE GULF OF ALASKA. THIS
WILL RESULT IN A MIX OF SUN AND CLOUDS THROUGHOUT THE DAY.
TEMPERATURES WILL STAY STEADY AT THEIR PEAK, REMAINING WELL
ABOVE NORMAL FOR LATE MARCH. SUNDAY NIGHT, AS THE TROUGH DRAWS
CLOSER, CLOUD COVER INCREASES ALONG WITH A SLIGHT CHANCE FOR
SHOWERS (15-20%) ACROSS THE EAST-CENTRAL OREGON AND WEST-CENTRAL
IDAHO MOUNTAINS, SPECIFICALLY NORTH OF A BAKER CITY TO MCCALL
LINE.
LONG TERM /MONDAY THROUGH FRIDAY/
A SPRING PATTERN WILL MANIFEST COME NEXT WEEK. THE FIRST
GLIMPSE OF THIS PATTERN WILL BE IN THE FORM OF A COLD FRONT LATE
MONDAY INTO EARLY TUESDAY. TEMPERATURES ON MONDAY WILL DEPEND
ON THE TIMING OF THIS FRONTAL PASSAGE, WITH ABOVE NORMAL
TEMPERATURES AHEAD OF IT AND NEAR TO BELOW NORMAL TEMPERATURES
BEHIND IT. THIS FRONTAL PASSAGE WILL ALSO OFFER OUR FIRST
CHANCES OF PRECIPITATION AS IT PASSES. MONDAY AFTERNOON,
PRECIPITATION CHANCES WILL INCREASE TO 30-65% (HIGHEST IN THE
CENTRAL IDAHO MOUNTAINS) THROUGH EARLY TUESDAY MORNING. THERE IS
SOME UNCERTAINTY REGARDING PRECIPITATION CHANCES TUESDAY
THROUGH WEDNESDAY, AS ZONAL FLOW MAY ALLOW FOR THE PASSAGE OF
SHORTWAVES IN THE MAIN FLOW ALOFT. ENSEMBLE GUIDANCE IS BACKING
OFF ON PRECIPITATION FOR TUESDAY, BUT AM MAINTAINING A SLIGHT
CHANCE TO CHANCE OF PRECIPITATION TO ACCOUNT FOR UNCERTAINTY.
CONFIDENCE INCREASES REGARDING THE NEXT SYSTEM TO COME MID-
WEEK. WEDNESDAY INTO THURSDAY, A GULF OF ALASKA LOW WILL DIG
DOWN ACROSS THE AREA. THIS WILL OFFER UP THE BEST CHANCE OF
PRECIPITATION AREA-WIDE AND BRING BELOW NORMAL TEMPERATURES
BEHIND A COLD FRONT. PRECIPITATION CHANCES WILL INCREASE THROUGH
WEDNESDAY, REACHING 60-90% AREA-WIDE BY LATE WEDNESDAY NIGHT
THROUGH THURSDAY. WEDNESDAY AFTERNOON WILL ALSO SUPPORT THE BEST
CHANCE FOR A THUNDERSTORM, WITH ENSEMBLE GUIDANCE BUILDING IN
WEAK INSTABILITY AS COOLING ALOFT STEEPENS LAPSE RATES.
UNCERTAINTY REMAINS REGARDING THE SPEED OF THE SYSTEM THIS FAR
OUT (AND THEREFORE ITS RESIDENCE TIME OVER US). HOWEVER,
PRECIPITATION WILL TAKE ON A SHOWERY NATURE, WITH COOL AIR ALOFT
PLUS DIURNAL HEATING, AND TAPER OFF LATE NEXT WEEK. THIS COOL
SYSTEM WILL LOWER SNOW LEVELS AND OFFER UP A CHANCE FOR OUR
MOUNTAINS TO GET SOME LATE SEASON SNOW. SNOW LEVELS THURSDAY
WILL DROP TO 2.5-4.5KFT MSL AND HOVER THERE THROUGH FRIDAY (WITH
THE LOWER BOUND OF THAT RANGE COMING OVERNIGHT THURSDAY).
WEDNESDAY THROUGH FRIDAY, THE CHANCE OF AT LEAST A FOOT OF SNOW
RANGES FROM 40-80% FOR PEAKS ABOVE 6500 FT MSL. MOUNTAIN
VALLEYS MAY EVEN PICK UP A FEW INCHES OF SNOW OVER THE SAME
PERIOD. WINDS WILL BE BREEZY TO GUSTY EACH DAY.
AVIATION /18Z FRIDAY THROUGH SATURDAY/
ISSUED 1130 AM MDT FRI MAR 27 2026 VFR. SURFACE WINDS: E-SE
5-15 KT WITH LOCALIZED GUSTS UP TO 22 KT THIS AFTERNOON,
BECOMING VARIABLE UP TO 10 KT OVERNIGHT. WINDS ALOFT AT 10KFT
MSL: S-W 5-15 KT.
KBOI...VFR. SURFACE WINDS: SE 8-13 KT WITH GUSTS UP TO 20 KT
THROUGH THE AFTERNOON. THEN SE UP TO 8 KT OVERNIGHT.
WEEKEND OUTLOOK...VFR THROUGH SUNDAY. INCREASING MID-HIGH CLOUDS
SATURDAY, THEN BROKEN-OVERCAST HIGH CLOUDS SUNDAY. BREEZY W-NW WIND
WITH GUSTS UP TO 22 KT SATURDAY AFTERNOON THEN UP TO 25 KT
SUNDAY AFTERNOON, OTHERWISE VARIABLE SURFACE WINDS LESS THAN 12
KT.
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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