605
FXUS65 KBOI 010548
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1148 PM MDT FRI JUL 31 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- HOT WITH WIDESPREAD WILDFIRE SMOKE PERSISTING ACROSS SOUTHEAST
OREGON AND MUCH OF SOUTHWEST IDAHO THROUGH SATURDAY.
- DRY COLD FRONT SATURDAY EVENING WILL BRING PERIOD OF CRITICAL
FIRE WEATHER CONDITIONS AND GUSTY WINDS.
- REMAINING DRY BUT NOT AS HOT SUNDAY THROUGH TUESDAY. THE HEAT
RETURNS BY MIDWEEK.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED 243 PM MDT FRI JUL 31 2026
AN UPPER HIGH OVER THE DESERT SW WILL KEEP THE HEAT ON THROUGH
SATURDAY. TEMPERATURES WILL AGAIN TOUCH 100 DEGREES AT LOWER
ELEVATIONS WITH LOCALLY HOTTER TEMPERATURES (MOUNTAIN HOME TO
HAGERMAN) PUSHING ABOVE 100 DEGREES ON SATURDAY. FLOW ALOFT
WILL INCREASE ON SATURDAY AS AN UPPER TROUGH PUSHES INTO THE PAC
NW. HIGHER, OPEN TERRAIN IN SE OREGON AND SW IDAHO WILL TAP
INTO THE SOUTHWEST WINDS, BRINGING GUSTS TO 30 MPH BY AFTERNOON.
THE UPPER TROUGH AND ACCOMPANYING COLD FRONT ADVANCE INLAND
SATURDAY EVENING PUSHING A DRY COLD FRONT INTO SE OREGON BY LATE
AFTERNOON, ADVANCING INTO SW IDAHO DURING THE EVENING. WINDS
GUSTS WILL BE STRONGEST ACROSS SE OREGON, ESPECIALLY ALONG THE
I-84 CORRIDOR BETWEEN BAKER CITY AND ONTARIO WHERE GUSTS TO 45
MPH ARE EXPECTED INTO SATURDAY NIGHT. FOR BAKER COUNTY HAVE
OPTED TO COVER THE WIND THREAT WITH AN ADVISORY PICKING UP WHERE
THE RED FLAG WARNING LEAVES OFF AS RELATIVE HUMIDITY WILL BE ON
IN THE INCREASE, BUT BUT GUSTY WINDS WILL CONTINUE INTO
SATURDAY NIGHT. ELSEWHERE WIND GUSTS TOP OUT BETWEEN 25 AND 40
MPH ACROSS SE OREGON AND THE SNAKE PLAIN/HIGHLANDS OF SW IDAHO
THROUGH SATURDAY NIGHT.
FOR SUNDAY THE POST FRONTAL AIR MASS IS DRY WITH HIGH
TEMPERATURES 10-15 DEGREES COOLER THAN SATURDAY. IT WILL REMAIN
BREEZY AS WESTERLY WINDS RESIDE THROUGH THE MIXED LAYER. THIS
WILL RESULT IN ELEVATED, BUT NOT QUITE CRITICAL FIRE WEATHER
CONDITIONS AS AFTERNOON RELATIVE HUMIDITY DROPS TO AROUND 10%
ACROSS LOWER ELEVATIONS. FORECAST MODELS ARE CUTTING DOWN ON
SMOKE COVERAGE FOR SUNDAY AS WESTERLY FLOW IN A WELL MIXED
ENVIRONMENT VENTS OUT THE SMOKE THAT HAS POOLED UP OVER THE
LAST WEEK(ISH) AND MODELED PLUMES FROM ONGOING FIRES ARE
TIGHTER. DO EXPECT SOME IMPROVEMENT GOING INTO EARLY NEXT WEEK,
BUT UNCERTAIN ON HOW MUCH, ESPECIALLY IF THERE ARE NEW STARTS OR
SATURDAY'S WIND/RH EVENT KICKS UP CURRENT ACTIVITY. SUNDAY
NIGHT WILL BE COOL COMPARED TO THE RECENT PAST WITH
TEMPERATURES DROPPING BELOW 60 ACROSS THE SNAKE PLAIN.
OFFICIALLY FOR BOISE THIS WOULD BE THE FIRST SUB-60 DEGREE
TEMPERATURE SINCE JULY 3RD.
LONG TERM /MONDAY THROUGH FRIDAY/
ISSUED 243 PM MDT FRI JUL 31 2026
AFTER THE AFOREMENTIONED COOL START, LOWER ELEVATIONS WILL SEE
ANOTHER DRY, SUB-90 DEGREE DAY ON MONDAY. WINDS WILL PICK UP
ACROSS SE OREGON AND THE SNAKE PLAIN OF IDAHO AS WESTERLY FLOW
ALOFT MIXES TO THE SURFACE. THE UPPER TROUGH PROVIDING THE
COOLER, BREEZY CONDITIONS WILL SLIDE EAST OF THE AREA TUESDAY,
ALLOWING FOR WARM TEMPERATURES TO RETURN. BY WEDNESDAY HIGHS ARE
BACK INTO THE MID-UPPER 90S ACROSS LOWER ELEVATIONS (SMOKE
COVERAGE/DENSITY DEPENDENT). THERE IS NO CHANCE FOR
PRECIPITATION NEXT WEEK AS MONSOON MOISTURE REMAINS BOTTLED UP
OVER THE FOUR CORNERS. THE HOT AND DRY CONDITIONS WILL BE
FAVORABLE FOR FIRE GROWTH SO SMOKE IS LIKELY TO INCREASE IN
COVERAGE AND DENSITY.
AVIATION /06Z SATURDAY THROUGH SUNDAY/
ISSUED 1127 PM MDT FRI JUL 31 2026
WILDFIRE SMOKE CREATING LOW VFR/MVFR VISIBILITY THROUGH SATURDAY
EVENING, WITH MTN OBSCURATIONS. LOCAL IFR ACROSS E OREGON AND ALONG
THE OR/ID BORDER. HOT TEMPS CREATING HIGH DENSITY ALTITUDE THROUGH
SATURDAY AFTERNOON. SURFACE WINDS: VARIABLE UNDER 10 KT, INCREASING
TO SW-NW 5-15 KT WITH GUSTS 15-25 KT SAT AFTERNOON. THEN, W-NW 10-20
KT WITH 25-45 KT GUSTS WITH COLD FRONT SAT NIGHT. WINDS ALOFT AT
10KFT MSL: SW 10-20 KT.
KBOI...LOW VFR VISIBILITY IN SMOKE, WITH POTENTIAL FOR MVFR
VISIBILITY RETURNING SATURDAY AFTERNOON THROUGH EARLY EVENING.
IMPROVING CONDITIONS SATURDAY NIGHT WITH GUSTY COLD FRONT. SURFACE
WINDS: LIGHT VARIABLE/SE AROUND 5 KT OVERNIGHT, THEN NW 5-15 KT BY
LATE SAT MORNING AND AFTERNOON.
WEEKEND OUTLOOK...GUSTY W-NW SURFACE WINDS TO 25-45 KT ARRIVING
SATURDAY EVENING/NIGHT WITH A DRY COLD FRONT, THEN GUSTS DECREASING
TO 15-25 KT SUNDAY. WILDFIRE SMOKE IS EXPECTED TO MIX OUT OF MOST
AREAS WITH THE COLD FRONT, BUT VISIBILITY REDUCTIONS STILL EXPECTED
NEAR WILDFIRES.
BOI WATCHES/WARNINGS/ADVISORIES
ID...AIR QUALITY ALERT UNTIL 2 PM MDT MONDAY FOR IDZ011-012-014-015-
029-033.
RED FLAG WARNING FROM 3 PM TO 9 PM MDT SATURDAY FOR IDZ400-402-
423.
OR...RED FLAG WARNING FROM 3 PM MDT /2 PM PDT/ TO 9 PM MDT /8 PM
PDT/ SATURDAY FOR ORZ670>675.
AIR QUALITY ALERT UNTIL 3 PM MDT /2 PM PDT/ MONDAY FOR
ORZ061>064.
WIND ADVISORY FROM 8 PM SATURDAY TO 2 AM PDT SUNDAY FOR ORZ062.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
AVIATION.....CH
SHORT TERM...DG
LONG TERM....DG
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