816
FXUS65 KBOI 312348
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
548 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 /00Z SATURDAY THROUGH SUNDAY/
ISSUED 536 PM MDT FRI JUL 31 2026
WILDFIRE SMOKE REDUCING VISIBILITY THROUGH SATURDAY. MOSTLY
MVFR TO LOWER VFR CONDITIONS. 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. THEN, SW-NW 5-15 KT WITH GUSTS 15-25 KT SAT
AFTERNOON. WINDS ALOFT AT 10KFT MSL: SW 10-20 KT.
KBOI...LOW VFR VISIBILITY IN SMOKE. POTENTIAL FOR MVFR VIS
RETURNING SAT PM. SURFACE WINDS: NW 5-10 KT THIS EVENING, THEN
LIGHT VARIABLE OR SE AROUND 5 KT AFTER SUNSET.
WEEKEND OUTLOOK...WILDFIRE SMOKE WILL KEEP WIDESPREAD VISIBILITY
REDUCTION IN PLACE THROUGH SATURDAY, MOSTLY ACROSS SE OREGON.
COVERAGE IS EXPECTED TO DECREASE AND VISIBILITY WILL IMPROVE ON
SUNDAY. HIGH DENSITY ALTITUDE DUE TO HOT CONDITIONS ON
SATURDAY. GUSTY SW-NW SURFACE WINDS 25 TO 40 KT SATURDAY
EVENING/NIGHT DECREASING TO 15-25 KT SUNDAY.
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.....SH
SHORT TERM...DG
LONG TERM....DG
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