944
FXUS65 KBOI 130539
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1139 PM MDT MON OCT 12 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- UNSETTLED CONDITIONS THROUGH EARLY TUESDAY, MAINLY ON THE
IDAHO SIDE, WITH SHOWERS MAINLY OVER MAGIC VALLEY AND BOISE
MOUNTAINS.
- COLD MORNING TEMPERATURES TONIGHT AND WEDNESDAY MORNING WILL
BRING PATCHY FROST AND NEAR-FREEZING CONDITIONS, WITH FROST
ADVISORIES IN EFFECT FOR VALLEY AREAS.
- WARM AND DRY CONDITIONS WEDNESDAY THROUGH NEXT WEEKEND.
TEMPERATURES REACHING 10 DEGREES ABOVE NORMAL BY FRIDAY.
SHORT TERM /THROUGH WEDNESDAY NIGHT/
ISSUED 202 PM MDT MON OCT 12 2026
THE CLOSED UPPER LEVEL LOW CENTER IS POSITIONED DIRECTLY OVER
THE REGION THIS AFTERNOON. THIS SYSTEM WILL CONTINUE TO TRIGGER
SCATTERED SHOWERS AND ISOLATED MOUNTAIN SNOW SHOWERS, PRIMARILY
ACROSS SOUTHWEST IDAHO THROUGH LATE THIS EVENING. SHOWER
ACTIVITY WILL GRADUALLY TAPER OFF FROM WEST TO EAST OVERNIGHT AS
THE LOW WEAKENS AND KICKS EASTWARD TOWARD THE ROCKIES.
PRECIPITATION AMOUNTS WILL REMAIN LIGHT, WITH VALLEY LOCATIONS
PICKING UP A FEW HUNDREDTHS OF AN INCH AND HIGHER ELEVATIONS
SEEING LESS THAN AN INCH OF LIGHT SNOW ABOVE 7000 FEET.
AS SHOWER ACTIVITY DIMINISHES OVERNIGHT, CLEARING SKIES AND
LIGHT WINDS WILL ALLOW FOR SIGNIFICANT RADIATIONAL COOLING. LOW
TEMPERATURES TONIGHT WILL FALL INTO THE LOWER TO MID 30S ACROSS
THE LOWER VALLEYS, WITH WIDESPREAD 20S IN THE HIGHER MOUNTAIN
VALLEYS. PATCHY FROST IS EXPECTED TO DEVELOP LATE TONIGHT INTO
EARLY TUESDAY MORNING ACROSS THE TREASURE VALLEY AND WESTERN
MAGIC VALLEY. THUS, A FROST ADVISORY HAS BEEN ISSUED FOR THE
SNAKE RIVER PLAIN. NOTE THAT PARTS OF THE MAGIC VALLEY MAY AVOID
WIDESPREAD FROST TONIGHT, AS LINGERING CLOUDS AND SHOWERS
THROUGH LATE MORNING COULD HOLD TEMPERATURES IN THE UPPER 30S.
A WEAK RIDGE OF HIGH PRESSURE BUILDS OVERHEAD TUESDAY AND
WEDNESDAY, BRINGING DRY CONDITIONS AND A SLIGHT MODERATING TREND
IN DAYTIME HIGHS. HOWEVER, ANOTHER COLD MORNING IS ON TAP FOR
WEDNESDAY MORNING UNDER CLEAR, CALM CONDITIONS. MINIMUM
TEMPERATURES WEDNESDAY MORNING WILL MIRROR TUESDAY MORNING,
KEEPING THE THREAT FOR LOCALIZED FROST AND NEAR-FREEZING VALLEY
TEMPERATURES INTACT BEFORE TEMPERATURES RECOVER SLIGHTLY
WEDNESDAY AFTERNOON. A FROST ADVISORY HAS BEEN ISSUED FOR
WEDNESDAY MORNING, THOUGH A FREEZE WARNING MAY BE NEEDED FROM
MOUNTAIN HOME THROUGH THE MAGIC VALLEY WHERE TEMPERATURES COULD
DROP INTO THE 30 TO 33 DEGREE RANGE. FROST AND FREEZES ARE
TYPICAL FOR THIS TIME OF YEAR, USUALLY OCCURRING IN THE FIRST
FEW WEEKS OF OCTOBER.
LONG TERM /THURSDAY THROUGH MONDAY/
ISSUED 202 PM MDT MON OCT 12 2026
WARM, DRY, AND PLEASANT CONDITIONS WILL END THE COMING WEEK AS
A PACIFIC RIDGE SHIFTS TO BE OVER THE GREAT BASIN. THIS RIDGE
WILL ALLOW TEMPERATURES OF 5-10 DEGREES ABOVE NORMAL. CLEAR
SKIES AND GOOD RADIATIONAL COOLING OVERNIGHT WILL ALLOW FOR A
THREAT OF MOUNTAIN VALLEY FOG OVERNIGHT INTO THE MORNINGS. A
WEAK SHORTWAVE LATE SUNDAY WILL HELP LOWER TEMPS A FEW DEGREES
COME MONDAY (ALTHOUGH STILL LEANING ABOVE NORMAL). FLOW ALOFT
WILL BECOME MORE ZONAL AS A RESULT, BEFORE BECOMING
SOUTHWESTERLY MONDAY AHEAD OF THE NEXT SYSTEM. IN THE 7-10 DAY
TIME FRAME, ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT ON ANOTHER
TROUGH DIGGING DOWN FROM THE GULF OF ALASKA. THIS WILL LIKELY
BRING INCREASING CHANCES OF PRECIPITATION AND COOLER CONDITIONS
BY MID- WEEK NEXT WEEK.
AVIATION /06Z TUESDAY THROUGH WEDNESDAY/
ISSUED 1139 PM MDT MON OCT 12 2026
GENERALLY VFR. SCATTERED RAIN SHOWERS AND LOW CLOUDS WILL BRING
INTERMITTENT MVFR CEILINGS TO THE MAGIC VALLEY THROUGH TOMORROW
MORNING. PATCHY VALLEY FOG IN CENTRAL ID MOUNTAINS BRINGING BRIEF
MVFR/IFR CONDITIONS. MOUNTAINS OBSCURED IN LOW CLOUDS AND
PRECIPITATION WITH SNOW LEVELS AROUND 4500-5500 FT MSL. WIDESPREAD
CLEARING TOMORROW EVENING. SURFACE WINDS: W-NW 5-15 KT. WINDS ALOFT
AT 10KFT MSL: N-NE 10-20 KT BECOMING N 20-30 KT BY TUES/12Z.
KBOI...VFR. SKIES CLEARING OVERNIGHT, WITH MOSTLY CLEAR SKIES
TUE/AM. SURFACE WINDS: NW 5-12 KT BECOMING VARIABLE LESS THAN 6 KT
LATE TUESDAY.
BOI WATCHES/WARNINGS/ADVISORIES
ID...FROST ADVISORY UNTIL 10 AM MDT WEDNESDAY FOR IDZ012-014-016.
OR...FROST ADVISORY UNTIL 10 AM MDT /9 AM PDT/ WEDNESDAY FOR ORZ064.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
AVIATION.....SA
SHORT TERM...JDS
LONG TERM....NF
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