997
FXUS65 KBOI 011811
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1211 PM MDT SAT AUG 1 2026
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- HOT WITH WIDESPREAD WILDFIRE SMOKE PERSISTING ACROSS SOUTHEAST
OREGON AND MUCH OF SOUTHWEST IDAHO THROUGH TODAY.
- DRY COLD FRONT THIS 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 MONDAY NIGHT/
ISSUED 332 AM MDT SAT AUG 1 2026
PER WATER VAPOR SATELLITE IMAGERY, AN UPPER-LEVEL LOW IS
SITTING JUST OFF THE BRITISH COLUMBIA COAST, AND WILL MOVE
ONSHORE OVER THE COURSE OF TODAY. THIS IS CONTRASTED WITH THE
STRONG UPPER-LEVEL RIDGE OVER THE DESERT SOUTHWEST, WHICH WILL
CONTINUE HOT AND DRY CONDITIONS FOR THE REGION TODAY.
TEMPERATURES WILL AGAIN TOUCH 100 DEGREES AT LOWER ELEVATIONS,
WITH LOCALLY HOTTER TEMPERATURES (MOUNTAIN HOME TO HAGERMAN)
PUSHING 100-105 DEGREES. FLOW ALOFT WILL INCREASE OUT OF THE
SOUTHWEST AS THE PRESSURE GRADIENT BETWEEN THE TROUGH AND RIDGE
INCREASES THROUGH THE DAY. THE HOT DIURNAL TEMPERATURES WILL
PROMOTE STRONG VERTICAL MIXING, CAUSING THE GUSTY WINDS ALOFT TO
MIX TO THE SURFACE. HIGHER, OPEN TERRAIN IN SE OREGON AND SW
IDAHO WILL TAP INTO THE SOUTHWEST WINDS, BRINGING GUSTS TO 30
MPH BY AFTERNOON. ADDITIONALLY, A DRY COLD FRONT FROM THE
UPPER-LEVEL TROUGH MOVING ACROSS THE SOUTHERN CANADIAN PROVINCES
WILL MOVE 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 TONIGHT.
WITH THESE INCREASED WIND SPEEDS THROUGHOUT THE DAY, ALONGSIDE
ONGOING WILDFIRES AND LOW MINIMUM RELATIVE HUMIDITIES, RED FLAG
WARNINGS ARE IN EFFECT THIS AFTERNOON INTO EVENING.
ADDITIONALLY, BAKER COUNTY IS UNDER A WIND ADVISORY AS RELATIVE
HUMIDITIES INCREASE IN THE EVENING HOURS WITH GUSTY WINDS
CONTINUING. ELSEWHERE, WIND GUSTS TOP OUT BETWEEN 25 AND 40 MPH
ACROSS SE OREGON AND THE SNAKE PLAIN/HIGHLANDS OF SW IDAHO
THROUGH SATURDAY NIGHT AS THE FRONT MOVES THROUGH.
SUNDAY WILL BE A CONSIDERABLE CHANGE OF PACE, WITH THE POST
FRONTAL AIR MASS HIGH TEMPERATURES 10-15 DEGREES COOLER THAN
TODAY. THE REGION WILL ALSO BECOME CONSIDERABLY DRIER STARTING
SUNDAY, WITH PWAT VALUES FALLING BENEATH THE 10TH PERCENTILE
(NEAR 0.3 INCHES). ADDITIONALLY, BREEZY WINDS WILL PERSIST AS
WESTERLY FLOW ALOFT CHANNELS THROUGH THE TERRAIN, PARTICULARLY
FROM MOUNTAIN HOME THROUGH THE WESTERN MAGIC VALLEY. FROM ALL OF
THESE FACTORS, ELEVATED FIRE WEATHER CONCERNS REMAIN. 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. MONDAY WILL CONTINUE THE TRENDS FROM
SUNDAY, WITH COOLER (BUT STILL WARM) TEMPERATURES, BREEZY
AFTERNOON WINDS, AND DRY.
LONG TERM /TUESDAY THROUGH SATURDAY/
ISSUED 332 AM MDT SAT AUG 1 2026
THE DESERT SOUTHWEST UPPER-LEVEL RIDGE WILL BE, YET AGAIN,
DRIVING THE SYNOPTIC PATTERN. CLUSTERS HAVE THE EXTENT OF THE
HIGHEST 500 MB HEIGHTS ASSOCIATED WITH THE RIDGE REACHING TO
THE CALIFORNIA COAST, THEREBY LIMITING ANY MONSOONAL MOISTURE
FROM GETTING NORTH TO OUR REGION. THUS, HOT AND DRY CONDITIONS
ARE EXPECTED TO RETURN AND STICK AROUND. BY WEDNESDAY, HIGHS
ARE BACK INTO THE MID-UPPER 90S/NEAR 100 DEGREES ACROSS LOWER
ELEVATIONS (SMOKE COVERAGE/DENSITY DEPENDENT). THERE IS NO
CHANCE FOR PRECIPITATION THROUGH THE PERIOD AS MONSOONAL
MOISTURE REMAINS BOTTLED UP OVER THE FOUR CORNERS REGION.
AVIATION /18Z SATURDAY THROUGH SUNDAY/
ISSUED 1151 AM MDT SAT AUG 1 2026
WIDESPREAD LOW-VFR AND AREAS MVFR VISIBILITY THROUGH THIS
EVENING DUE TO WILDFIRE SMOKE. HOT TEMPERATURES CREATING HIGH
DENSITY ALTITUDE THIS AFTERNOON. SURFACE WINDS: SW-NW 5-15 KT
WITH GUSTS TO 15-25 KT THIS AFTERNOON, THEN, W-NW 10-20 KT WITH
25-45 KT GUSTS WITH COLD FRONT TONIGHT.
KBOI...WILDFIRE SMOKE WILL CONTINUE TO REDUCE VISIBILITY, WITH
MOSTLY LOW VFR CONDITIONS. BRIEF MVFR POSSIBLE THROUGH EARLY
EVENING. WESTERLY SURFACE WINDS WILL REMAIN IN PLACE THROUGH
SUNDAY.
SUNDAY OUTLOOK...GUSTY W-NW SURFACE WINDS 10-20 KT WITH GUSTS TO
30 KT THROUGH SUNSET. WILDFIRE SMOKE IS EXPECTED TO MIX OUT
WHICH WILL IMPROVE NEAR SURFACE VISIBILITY WHILE WESTERLY WINDS
ALOFT TRANSPORT ELEVATED SMOKE LAYERS INTO THE REGION.
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 THIS AFTERNOON TO 9 PM MDT THIS
EVENING FOR IDZ400-402-423.
OR...RED FLAG WARNING FROM 3 PM MDT /2 PM PDT/ THIS AFTERNOON TO 9
PM MDT /8 PM PDT/ THIS EVENING FOR ORZ670>675.
AIR QUALITY ALERT UNTIL 3 PM MDT /2 PM PDT/ MONDAY FOR
ORZ061>064.
WIND ADVISORY FROM 8 PM THIS EVENING 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.....DG
SHORT TERM...CH
LONG TERM....CH
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