278
FXUS65 KBOI 270629
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1229 AM MDT SUN SEP 27 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- MOSTLY CLOUDY AND SLIGHTLY WARMER SUNDAY AND MONDAY,
THE MOSTLY CLEAR BUT CONTINUED WARMING THROUGH THE WEEK.
- A SLIGHT CHANCE OF SHOWERS AND AFTERNOON THUNDERSTORMS IN
SOUTHEAST OREGON AND CENTRAL IDAHO ON SUNDAY.
SHORT TERM /THROUGH TUESDAY NIGHT/
ISSUED 218 PM MDT SAT SEP 26 2026
YESTERDAY'S COLD FRONT MOVED RAPIDLY EASTWARD ACROSS OUR CWA BUT GOT
ONLY AS FAR SOUTH AS NORTHERN NEVADA WHERE IT HAS BECOME STATIONARY.
FROM THERE THE FRONTAL ZONE WILL NOW MOVE SLOWLY NORTHWARD AGAIN AS
A DIFFUSE WARM FRONT TONIGHT THROUGH SUNDAY UNDER SOUTHWESTERLY FLOW
ALOFT AHEAD OF THE NEXT INCOMING PACIFIC UPPER TROUGH. MIDDLE AND
HIGH CLOUDS WILL INCREASE FROM SOUTH TO NORTH TONIGHT AND LEAD TO A
10-20 PERCENT CHANCE OF SHOWERS ON SUNDAY. THERE WILL ALSO BE JUST
ENOUGH INSTABILITY FOR A SLIGHT (10%) CHANCE OF THUNDERSTORMS IN
THE CENTRAL IDAHO MOUNTAINS SUNDAY AFTERNOON AND EARLY EVENING.
THE INCOMING UPPER TROUGH WILL BECOME A CLOSED LOW IN NEVADA BY
MONDAY AND TAKE THE FRONTAL ZONE BACK OUT OF OUR AREA, RESULTING
IN CLEARING SKIES IN OREGON MONDAY AND IN IDAHO MONDAY NIGHT.
GRADUAL WARMING IS EXPECTED THROUGH TUESDAY, DUE TO CLOUDS AND
THE WARM FRONT TONIGHT AND SUNDAY, AND THE DEPARTURE OF THE COOL
UPPER LOW INTO NEVADA ON MONDAY. NO SIGNIFICANT WINDS THROUGH
THE PERIOD.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
ISSUED 218 PM MDT SAT SEP 26 2026
HIGH PRESSURE WILL REMAIN ALOFT TUESDAY THROUGH LATE WEEK,
CONTINUING A WARMING TREND WITH DRY CONDITIONS AREA-WIDE.
TEMPERATURES WILL MAINLY HOVER NEAR-NORMAL ON TUESDAY, BEFORE
GRADUALLY CLIMBING 5 TO 10 DEGREES ABOVE NORMAL WEDNESDAY
THROUGH THURSDAY. LATE THURSDAY THROUGH FRIDAY, LONG-RANGE
GUIDANCES HINT AT A SHORTWAVE TROUGH DIGGING ACROSS THE REGION.
THERE IS CONSIDERABLE GUIDANCE UNCERTAINTY OVER ITS TIMING AND
BEHAVIOR AS IT PASSES OUR AREA. FOR NOW, A COOLING TREND AND
MOSTLY DRY CONDITIONS ARE EXPECTED FRIDAY THROUGH SATURDAY.
AVIATION /06Z SUNDAY THROUGH MONDAY/
ISSUED 1225 AM MDT SUN SEP 27 2026
MAINLY VFR WITH MID TO HIGH CLOUDS INCREASING OVERNIGHT THROUGH
SUNDAY. ISOLATED TO SCATTERED LIGHT RAIN SHOWERS AND VIRGA WILL
LIFT NORTH ACROSS THE AREA OVERNIGHT THROUGH SUNDAY. SURFACE
WINDS: VARIABLE LESS THAN 10 KT THROUGH SUNDAY MORNING, BECOMING
NW 5-15 KT WITH GUSTS TO 25 KT EAST OF KBOI AFTER SUN/21Z.
WINDS ALOFT AT 10KFT MSL: SW 10-20 KT.
KBOI...VFR. VIRGA OR LIGHT RAIN IN THE VICINITY THROUGH MORNING.
A 15% CHANCE OF RAIN REACHING THE GROUND AT THE TERMINAL.
SURFACE WINDS: SE AROUND 5 THROUGH MORNING, BECOMING NW 7-12 KT
THIS AFTERNOON, WITH GUSTS TO AROUND 20 KT MID-AFTERNOON
THROUGH EARLY EVENING.
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.....SH
SHORT TERM...LC
LONG TERM....JY
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