122
FXUS65 KBOI 292021
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
221 PM MDT WED JUL 29 2026
KEY MESSAGES
- ISOLATED SEVERE THUNDERSTORMS OVER SOUTH-CENTRAL IDAHO LATE
THIS AFTERNOON THROUGH EARLY EVENING POSE A THREAT FOR
ISOLATED STRONG OUTFLOW WINDS UP TO 60 MPH.
- SMOKE WILL LIMIT HIGH TEMPERATURES AND CONTINUE DEGRADED AIR
QUALITY THROUGH THE END OF THE WEEK.
- A DRY COLD FRONTAL PASSAGE SATURDAY INTO SUNDAY WILL BRING
GUSTY WINDS AND ELEVATED FIRE WEATHER CONCERNS, WITH GUSTY
CONDITIONS CONTINUING INTO SUNDAY DUE TO A TIGHT SURFACE
PRESSURE GRADIENT.
SHORT TERM /THROUGH FRIDAY NIGHT/
AN UPPER LEVEL RIDGE CENTERED OVER THE INTERMOUNTAIN WEST WILL
MAINTAIN HOT AND DRY CONDITIONS ACROSS SOUTHEAST OREGON AND
SOUTHWEST IDAHO THROUGH FRIDAY NIGHT. HIGH TEMPERATURES WILL BE
MODERATED DUE TO THE PERSISTENT SMOKE ACROSS MUCH OF THE
FORECAST AREA BUT SHOULD STILL REACH ABOVE NORMAL FOR MANY
LOCATIONS. LOWER VALLEY LOCATIONS WILL RANGE FROM THE UPPER 90S
TO LOW 100S, ACCOMPANIED BY LOW RELATIVE HUMIDITY VALUES DURING
THE PEAK HEATING HOURS.
ISOLATED SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP LATE THIS
AFTERNOON INTO EARLY THIS EVENING ACROSS SOUTH-CENTRAL IDAHO,
PARTICULARLY WITHIN SOUTHERN TWIN FALLS COUNTY AND THE WESTERN
MAGIC VALLEY. THERE IS SUFFICIENT MIDDLE LEVEL MOISTURE AND
STRONG ENOUGH SURFACE HEATING TO YIELD ELEVATED INSTABILITY
ACROSS SOUTH-CENTRAL IDAHO. INVERTED-V THERMODYNAMIC PROFILES ON
FORECAST SOUNDINGS HIGHLIGHT A FAVORABLE ENVIRONMENT FOR
ISOLATED STRONG OUTFLOW WINDS UP TO 60 MPH WHICH HAS BEEN
OUTLINED IN SPC'S MARGINAL RISK TODAY.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
A PATTERN TRANSITION BEGINS SATURDAY AS AN UPPER LEVEL TROUGH
MOVES ACROSS THE PACIFIC NORTHWEST AND PUSHES A DRY COLD FRONT
THROUGH SOUTHEAST OREGON AND SOUTHWEST IDAHO SATURDAY AFTERNOON
INTO SUNDAY MORNING. MINIMAL ATMOSPHERIC MOISTURE WILL LIMIT
PRECIPITATION POTENTIAL WITH THIS PASSAGE, KEEPING CONDITIONS
PREDOMINANTLY DRY ACROSS THE AREA.
THE PRIMARY IMPACT FROM THIS FRONTAL PASSAGE WILL BE STRONG AND
GUSTY WINDS. WEST TO NORTHWEST SURFACE WINDS WILL INCREASE TO
20 TO 30 MPH WITH GUSTS UP TO 40 MPH ALONG AND BEHIND THE FRONT
SATURDAY AFTERNOON AND EVENING. COMBINED WITH LOW RELATIVE
HUMIDITY, THESE GUSTY WINDS WILL RESULT IN HEIGHTENED FIRE
WEATHER CONCERNS ACROSS THE REGION. THIS WIND THREAT WILL
CONTINUE INTO SUNDAY ACROSS SOUTHWEST IDAHO WITH THE TIGHT
SURFACE PRESSURE GRADIENT BEHIND THE EXITING FRONT.
BEHIND THE FRONT, DAYTIME TEMPERATURES WILL DROP 5 TO 10 DEGREES
ON SUNDAY AND MONDAY, BRINGING HIGH TEMPERATURES BACK DOWN TO
NEAR SEASONAL NORMALS. HIGH PRESSURE WILL BEGIN TO REBUILD OVER
THE GREAT BASIN TUESDAY INTO WEDNESDAY, LEADING TO LIGHTER WINDS
AND A GRADUAL WARMING TREND THROUGH MID-WEEK.
AVIATION /18Z WEDNESDAY THROUGH THURSDAY/
ISSUED 1231 PM MDT WED JUL 29 2026
WIDESPREAD WILDFIRE SMOKE REDUCING VISIBILITIES WITH MVFR TO
IFR CONDITIONS. MOUNTAINS OBSCURED IN SMOKE. ISOLATED
THUNDERSTORMS SE OF KTWF AND KJER THIS AFTERNOON WITH GUSTY
WINDS UP TO 45KT IN VICINITY OF STORMS. SURFACE WINDS: SW-NW
5-10 KT IN THE AFTERNOON. WINDS ALOFT AT 10KFT MSL: SW 5-15KT.
KBOI...MVFR CONDITIONS FROM WILDFIRE SMOKE THROUGH EARLY
AFTERNOON. IMPROVEMENTS IN VISIBILITIES POSSIBLY LATER
THIS AFTERNOON AND EVENING. SURFACE WINDS SE 4-7KT THIS
MORNING, BECOMING NW 5-10 KT WITH GUSTS UP TO 17 KT IN THE
AFTERNOON.
BOI WATCHES/WARNINGS/ADVISORIES
ID...AIR QUALITY ALERT UNTIL 2 PM MDT FRIDAY FOR IDZ011>015-028-029-
033.
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR IDZ426.
AIR QUALITY ALERT UNTIL 1 PM MDT THURSDAY FOR IDZ016-030.
OR...AIR QUALITY ALERT UNTIL 1 PM MDT /NOON PDT/ FRIDAY FOR
ORZ062>064.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
SHORT TERM...JDS
LONG TERM....JDS
AVIATION.....JDS
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