227
FXUS65 KBOI 202021
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
221 PM MDT SAT JUN 20 2026
KEY MESSAGES
- SHOWERS NORTH AND SCATTERED THUNDERSTORMS SOUTH FOR THE REST
OF THIS AFTERNOON, FOLLOWED BY GRADUAL CLEARING TONIGHT.
- DAYTIME TEMPERATURES REMAINING NEAR NORMAL THROUGH SUNDAY,
THEN HOTTER AND DRIER MONDAY THROUGH WEDNESDAY, AND REMAINING
HOT AND DRY THURSDAY.
SHORT TERM /THROUGH MONDAY NIGHT/
TODAY'S RAIN HAS GREATLY MOISTENED THE LOWER ATMOSPHERE AND
SHOWERS SHOULD KEEP NORTHERN AREAS COOL, MOIST, AND STABLE
THE REST OF TODAY, WITH PARTIAL CLEARING TONIGHT. SOUTHERN
AREAS, HOWEVER, HAVE PARTIALLY CLEARED AND RAPID DESTABILIZATION
HAS LED TO THUNDERSTORM DEVELOPMENT THAT WILL CONTINUE THE
REST OF THE AFTERNOON, ENDING EARLY EVENING IN SOUTH-
CENTRAL IDAHO. THE CLEARING AND COOLER OVERNIGHT AND MOSTLY
SUNNY SUNDAY. CONTINUED MOSTLY CLEAR INTO MONDAY AND 3 TO 5
DEGREES WARMER THAN SUNDAY.
LONG TERM /TUESDAY THROUGH SATURDAY/
A RIDGE OF HIGH PRESSURE WILL CONTINUE TO BUILD OVER THE WEST
COAST THROUGH THURSDAY, BRINGING A GRADUAL WARMING AND DRYING
TREND THROUGH THE MIDDLE OF THE WEEK. HOT DAYTIME TEMPERATURES
WILL PEAK ON WEDNESDAY, WITH VALLEYS SEEING HIGHS IN THE UPPER
90S AND NEAR 100F. HIGHER ELEVATIONS WILL SEE TEMPERATURES IN
THE UPPER 80S. A WEAK SHORTWAVE TROUGH WILL HELP COOL
TEMPERATURES DOWN AND BRING A LOW CHANCE OF MOUNTAIN SHOWERS
ON THURSDAY. CONDITIONS WILL BRIEFLY DRY OUT LATE THURSDAY INTO
EARLY FRIDAY. THEN, A MUCH MORE IMPRESSIVE CLOSED LOW PRESSURE
SYSTEM WILL MOVE INTO THE PACIFIC NORTHWEST ON FRIDAY, BRINGING
WIDESPREAD PRECIPITATION AND COOLER TEMPERATURES THROUGH THE
WEEKEND. MODEL AGREEMENT IN THE STORM TRACK OF THIS LOW REMAINS
HIGH THROUGH FRIDAY-EARLY SATURDAY, BUT DISAGREEMENT REMAINS ON
HOW LONG THE LOW WILL LINGER OVER THE REGION INTO THE WEEKEND.
AVIATION /18Z SATURDAY THROUGH SUNDAY/
ISSUED 1117 AM MDT SAT JUN 20 2026
VFR. RAIN SHOWERS IN THE CENTRAL ID MOUNTAINS TODAY, WITH
SCATTERED THUNDERSTORMS DEVELOPING OVER THE NV BORDER AND NEAR
KTWF THIS EVENING. OUTFLOW WINDS UP TO 40 KT, BRIEF HEAVY RAIN,
AND LIGHTNING ARE THE MAIN HAZARDS. MOUNTAIN OBSCURATION IN
MOUNTAIN SHOWERS. CLEARING SKIES OVERNIGHT. SURFACE WINDS:
W-NW 5-15 KT WITH GUSTS TO 25 KT. WINDS ALOFT AT 10KFT: W-NW
10-20 KT.
KBOI...VFR. MOUNTAINS OBSCURED NE OF TERMINAL IN PRECIPITATION.
SHOWERS ENDING IN THE EARLY AFTERNOON. SURFACE WINDS: NW 5-15KT
THEN VARIABLE LESS THAN 10 KT .
SUNDAY OUTLOOK...VFR AND CLEARING SKIES SUNDAY MORNING, WITH
BREEZY W-NW WINDS SUNDAY AFTERNOON.
FIRE WEATHER
RAIN HAS GREATLY MOISTENED THE LOWER ATMOSPHERE SINCE YESTERDAY,
AND CLEARING SKIES IN SOUTHERN ZONES HAS LED TO RAPID
DESTABILIZATION, AND DEVELOPMENT OF THUNDERSTORMS IN ZONES 670
672 AND 423, AND AS OF 2 PM MDT ENTERING 426. THESE ZONES WILL
REMAIN UNDER A RED FLAG WARNING FOR LIGHTNING UNTIL 6 PM MDT.
NORTHERN ZONES SHOULD CONTINUE CLOUDY AND SHOWERY THE REST OF
TODAY, WITH THE COOL TEMPERATURES KEEPING THE AIR MASS STABLE
AND INHIBITING THUNDERSTORM DEVELOPMENT.
BOI WATCHES/WARNINGS/ADVISORIES
ID...RED FLAG WARNING UNTIL 6 PM MDT THIS EVENING FOR IDZ423-426.
OR...RED FLAG WARNING UNTIL 5 PM PDT THIS AFTERNOON FOR ORZ670-672.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
SHORT TERM...LC
LONG TERM....SA
AVIATION.....SA
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