427
FXUS65 KBOI 230910
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
310 AM MDT SAT MAY 23 2026
KEY MESSAGES
- MOSTLY DRY WITH TEMPERATURES 10 TO 15 DEGREES ABOVE NORMAL
THROUGH MEMORIAL DAY.
- GUSTY WINDS MONDAY AHEAD OF A PACIFIC COLD FRONT, RESULTING
IN ELEVATED FIRE WEATHER CONDITIONS.
- MUCH COOLER WITH GUSTY WINDS AND A CHANCE OF SHOWERS AND
THUNDERSTORMS TUESDAY AND WEDNESDAY. SHOWERS IN IDAHO
THURSDAY, THEN DRYING AND WARMING FRIDAY.
SHORT TERM /THROUGH MONDAY NIGHT/
NO CHANGE TO CURRENT WARMING FORECAST THROUGH MONDAY (MEMORIAL
DAY). MOST AREAS WILL ALSO BE GRADUALLY DRIER, BUT ISOLATED
THUNDERSTORMS WILL DEVELOP LATE TODAY/EVENING NEAR THE OR/NV
BORDER, AND ALONG ALL OF THE NORTHERN NV BORDER SUNDAY
AFTERNOON/EVENING AND AGAIN MONDAY AFTERNOON/EVENING. THE HOT,
DRY AIR, AND ISOLATED THUNDERSTORMS WILL INCREASE FIRE DANGER
IN SOUTHERN MALHEUR COUNTY WHERE GRASSES HAVE ALREADY BECOME
CRITICALLY DRY. A DEEP UPPER LOW FROM THE GULF OF ALASKA WILL
PUSH A STRONG COLD FRONT ACROSS SOUTHEAST OR MONDAY EVENING AND
WESTERN ID OVERNIGHT, BRINGING A WIND SHIFT FROM SOUTHEAST TO
STRONGER NORTHWESTERLY, RAPID COOLING, AND A 20-40 PERCENT
CHANCE OF POST-FRONTAL SHOWERS AND THUNDERSTORMS. THE SUPPORTING
UPPER LOW IS FORECAST TO TRACK FROM JUST WEST OF VANCOUVER
ISLAND MONDAY AFTERNOON TO WESTERN OR MONDAY NIGHT, SLIGHTLY
WEST OF PREVIOUS FORECASTS. MONDAY NIGHT SHOULD THEREFORE BE
WARMER THAN PREVIOUSLY FORECAST ESPECIALLY ON THE IDAHO SIDE.
LONG TERM /TUESDAY THROUGH SATURDAY/
THE STRONG COLD FRONT SHOULD BE IN WESTERN IDAHO EARLY TUESDAY
MORNING AND THE WESTERN MAGIC VALLEY BEFORE NOON. BUT WITH THE
SUPPORTING UPPER LOW HEADING SSE INTO NEVADA, THE FORWARD SPEED
OF THE FRONT WILL BE SLOWED AND WINDS NOT AS STRONG AS IF THE
UPPER LOW WERE TO PUSH DUE EASTWARD. EVEN SO, THE AIR BEHIND
THE FRONT WILL BE 20 TO 25 DEGREES COOLER THAN AHEAD OF IT AND
WILL BE STRONGLY FELT TUESDAY. SHOWERS AND AFTERNOON THUNDERSTORMS
WILL BE MORE NUMEROUS TUESDAY AND WEDNESDAY BUT RAINFALL AMOUNTS
WILL STILL BE RELATIVELY LIGHT, RANGING FROM LESS THAN .10 INCH
IN THE SNAKE BASIN AND MOST OF EASTERN OR, TO .10 TO .25 INCH
IN SOUTHERN HIGHLANDS AND MOUNTAINS, AND .25 TO .50 INCH IN
VALLEY COUNTY, ID, HEAVIEST IN EASTERN VALLEY COUNTY. SHOWERS
WILL CONTINUE INTO THURSDAY ON THE IDAHO SIDE WHEN THE UPPER
LOW IS STILL IN CENTRAL NV. IN FACT, LATEST MODELS HAVE THURSDAY
AFTERNOON/EVENING EVEN WETTER THAN TUESDAY. BUT FRIDAY AND
SATURDAY LOOK DRIER AND WARMER AS THE UPPER LOW SHOULD THEN BE
IN COLORADO.
AVIATION /06Z SATURDAY THROUGH SUNDAY/
ISSUED 1002 PM MDT FRI MAY 22 2026
VFR, WITH MOSTLY CLEAR SKIES OVERNIGHT THROUGH MORNING. ISOLATED
THUNDERSTORMS NEAR NV BORDER SATURDAY AFTERNOON. SURFACE WINDS:
VARIABLE OR SE LESS THAN 10 KT OVERNIGHT THROUGH MORNING, THEN
W-NW 5-15 KT SATURDAY AFTERNOON WITH GUSTS UP TO 20 KT IN SE OR
AND MAGIC VALLEY.
KBOI...VFR. SURFACE WINDS: SE UNDER 10 KT OVERNIGHT THROUGH
MORNING, BECOMING NW 7-12 KT IN THE AFTERNOON.
SUNDAY OUTLOOK...VFR WITH MOSTLY CLEAR SKIES SUNDAY, EXCEPT
ISOLATED THUNDERSTORMS NEAR THE ID/NV BORDER IN THE AFTERNOON
WINDS SE OR VARIABLE 5-10 KT IN THE MORNING AND W-NW 5-15 KT IN
THE 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
SHORT TERM...LC
LONG TERM....LC
AVIATION.....JY
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