351
FXUS65 KBOI 121740
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1140 AM MDT SUN APR 12 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- ISOLATED AFTERNOON THUNDERSTORMS OVER SOUTHWEST IDAHO TODAY
WITH GUSTY OUTFLOW WINDS.
- SLIGHTLY BELOW NORMAL TEMPERATURES WITH VALLEY RAIN SHOWERS
AND MOUNTAIN SNOW SHOWERS TODAY THROUGH TOMORROW MORNING.
- MUCH COOLER TEMPERATURES WITH PERIODS OF PRECIPITATION
WEDNESDAY THROUGH FRIDAY.
SHORT TERM /THROUGH TUESDAY NIGHT/
ISSUED 313 AM MDT SUN APR 12 2026
WIDESPREAD PRECIPITATION IS FILLING IN SOUTH OF THE SNAKE RIVER
VALLEY AS OF 3AM MDT. THIS IS THE FIRST PUSH OF PRECIPITATION
ALONG THE OUTER BAND OF THE COASTAL LOW CURRENTLY MOVING INLAND
OVER NORTHERN CALIFORNIA. THIS WILL PUSH NORTHWARD THROUGHOUT
THE MORNING, BRINGING WIDESPREAD RAIN BELOW ABOUT 7000 FEET MSL.
MUCH COOLER AIR WILL MOVE IN BEHIND THIS INITIAL PUSH OF
PRECIPITATION LATER TODAY. TEMPERATURES WILL DROP ABOUT 5-10
DEGREES WITH THIS COOLER AIR, WITH SNOW LEVELS DROPPING TO
5500-6500 FEET MSL BY MID-MORNING.
WEAK INSTABILITY EXISTS MAINLY OVER HIGH TERRAIN IN CENTRAL
IDAHO DOWN TO THE MAGIC VALLEY AND NEAR THE ID-NV BORDER. THIS
WILL SUPPORT A SLIGHT CHANCE OF THUNDERSTORMS LATE THIS MORNING
THROUGH THE EARLY EVENING. SOME STORMS COULD BE STRONG WITH
GUSTY OUTFLOW WINDS UP TO 50 MPH THANKS TO ELEVATED WINDS ALOFT
WITH THE INCOMING LOW. HOWEVER, THE BEST CONDITIONS FOR ANY OF
THESE STRONGER THUNDERSTORMS IS OVER EASTERN IDAHO.
AS THE LOW MOVES EAST OF SOUTHERN IDAHO LATE SUNDAY, WRAPAROUND
MOISTURE AND COOLER NORTHERLY FLOW ALOFT WILL PUSH A SECONDARY
BAND OF PRECIPITATION INTO THE REGION EARLY MONDAY. THIS WILL
BRING MUCH LOWER SNOW LEVELS (4500-5500 FEET MSL) AND
WIDESPREAD PRECIPITATION TO THE REGION THROUGH MONDAY MORNING.
MOUNTAIN VALLEYS COULD SEE 1-3 INCHES OF SNOW, MOUNTAIN PASSES
ON US95 AND ID21 COULD SEE UP TO 6 INCHES OF SNOW, AND HIGH
PEAKS OVER 8000 FEET COULD SEE UP TO 12 INCHES OF SNOW BY MONDAY
MORNING. LIQUID TOTALS FROM SUNDAY AND MONDAY'S PERIODS OF
PRECIPITATION WILL REACH 0.50-1.0 INCHES OF RAIN NORTH OF THE
TREASURE VALLEY, WITH LOCALLY HIGHER AMOUNTS OVER HIGH TERRAIN.
AREAS NEAR THE NEVADA BORDER WILL REACH 0.10-0.25 INCHES OF
RAIN. PRECIPITATION WILL TAPER OFF MONDAY EVENING AS A BRIEF
DRY PERIOD MOVES IN ON TUESDAY.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
ISSUED 313 AM MDT SUN APR 12 2026
PRECIPITATION WILL RETURN WEDNESDAY, AFTER TUESDAY'S BRIEF
LULL. AS A LOW DIGS DOWN THE COAST OF BRITISH COLUMBIA,
WIDESPREAD PRECIPITATION WILL SET IN ACROSS THE AREA ALONG A
COLD FRONT. PRECIPITATION WILL LINGER THROUGH THURSDAY AS THE
MAIN LOW MOVES OVER OUR AREA. TEMPERATURES ON WEDNESDAY WILL BE
AROUND 10 DEGREES BELOW NORMAL, COOLING TO 10-15 DEGREES BELOW
NORMAL THURSDAY FOLLOWING THE COLD FRONT. RAIN WON'T BE THE
ONLY PRECIP TYPE IN PLAY WITH THIS SYSTEM. THE 500MB HEIGHTS ARE
IN THE 5-15TH PERCENTILE OF CLIMATOLOGY WILL SUPPORT LOWERING
SNOW LEVELS, FROM 4.5-6.5 KFT WEDNESDAY AFTERNOON TO VALLEYS
FLOORS COME THURSDAY. BREEZY WINDS WILL ALSO ACCOMPANY THIS
SYSTEM WEDNESDAY/THURSDAY. OVER THE COURSE OF WEDNESDAY THROUGH
THURSDAY, LIQUID PRECIPITATION TOTALS OF 0.15-0.50 INCHES ARE
EXPECTED THROUGHOUT E-OREGON AND WITHIN THE SNAKE PLAIN, WITH
0.6-1.5 INCHES OVER THE BOISE/WEST CENTRAL MOUNTAIN ZONES AND
HIGHER PEAKS ELSEWHERE. REGARDING SNOWFALL, MOUNTAINS WILL
RECEIVE 8-14 INCHES BY THURSDAY MORNING (1-4 INCHES IN HIGHER
ELEVATION MOUNTAIN VALLEYS), LOCATIONS DOWN TO 4500 FT MSL WILL
GENERALLY SEE UNDER AN INCH OF SNOW BY THURSDAY MORNING. THROUGH
THURSDAY AFTERNOON, LOCATIONS DOWN TO 4500 FT CAN SEE
ADDITIONAL AMOUNTS UP TO AN INCH, WITH 1-3 INCHES OF ADDITIONAL
SNOWFALL OVER THE WEST CENTRAL MOUNTAINS. TREASURE VALLEY SITES
COULD ALSO SEE SNOW FLURRIES THURSDAY, ALTHOUGH LITTLE TO NO
ACCUMULATION IS EXPECTED.
A WARMING AND DRYING TREND WILL SET IN BEYOND THURSDAY, AS THE
SYSTEM MOVES EAST AND RIDGING BUILDS IN ACROSS THE AREA.
TEMPERATURES WILL RETURN TO NEAR NORMAL COME SATURDAY, WARMING
EVEN MORE SUNDAY. THE DRY CONDITIONS DON'T APPEAR TO LAST TOO
LONG, AS ANOTHER SYSTEM WILL IMPACT THE AREA COME EARLY NEXT
WEEK.
AVIATION /18Z SUNDAY THROUGH MONDAY/
ISSUED 1135 AM MDT SUN APR 12 2026
WIDESPREAD RAIN SHOWERS CONTINUE TODAY. ISOLATED THUNDERSTORMS
ACROSS THE AREA COULD PRODUCE HEAVY RAIN AND 25 MPH OUTFLOWS.
A STRONG FRONTAL PASSAGE IN THE MAGIC VALLEY WILL BRING GUSTS UP
TO 45 MPH THIS AFTERNOON. PRECIPITATION MOVES NORTH BRIEFLY
TONIGHT, BEFORE MOVING BACK SOUTH TOMORROW MORNING. SURFACE
WINDS: BECOMING S-W 10-20 KT WITH GUSTS TO 20-30 KT. WINDS
ALOFT AT 10KFT MSL: SW 20-35 KT
KBOI...RAIN SHOWERS THROUGH THE DAY BRING MVFR CONDITIONS. THERE
IS A 10% CHANCE OF THUNDER THIS AFTERNOON, WHICH MAY BRING GUSTY
WINDS. THEN A DRIER PERIOD OVERNIGHT BEFORE MORE RAIN TOMORROW
MORNING. SURFACE WINDS VARIABLE IN SHOWERS 5-15 KT, STRAY GUSTS
UP TO 25 KT FROM DISTANT STORMS ARE POSSIBLE THIS AFTERNOON.
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.....JM
SHORT TERM...SA
LONG TERM....NF
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