642
FXUS65 KBOI 291546
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
946 AM MDT FRI AUG 29 2025
DISCUSSION
PWS HAVEN'T DECREASED AS MUCH AS MODELS WERE PROJECTING, AS THIS
MORNING'S SOUNDING HAS 0.79 INCHES WHICH IS STILL ABOVE THE 75TH
PERCENTILE FOR THIS TIME OF YEAR. ADDITIONALLY, THIS MORNING'S
SOUNDING REVEALS SOME INSTABILITY ALREADY PRESENT IN THE
ATMOSPHERE. ABOUT 83 J/KG OF SBCAPE WILL LIKELY RISE CLOSER TO
200-400 J/KG BY THIS AFTERNOON AS THE MORNING INVERSION WEAKENS
AND MIXING INCREASES. MODELS PROJECT A SIMILAR DAY TO YESTERDAY,
ISOLATED STORMS AND SHOWERS IN BAKER COUNTY, ID/OR/NV BORDER
AREA, AND NOW S-CENTRAL ID. WE'RE STILL EXPECTING OUTFLOW GUSTS
UP TO 45 MPH AND MODERATE RAINFALL RATES. GIVEN A STORM
YESTERDAY STRENGTHENED AND LIKELY PRODUCED 1 INCH DIAMETER
HAIL, THE SAME CANNOT BE WRITTEN OFF TODAY IN A SIMILAR
ENVIRONMENT. CONDITIONS ARE STILL ON TRACK TO WARM AND DRY OUT
THIS WEEKEND.
THE OTHER FORECAST HIGHLIGHT IS THE SMOKE FROM OREGON. VISIBLE
ON SATELLITE IS A LARGE PLUME OF WILDFIRE SMOKE MOVING ACROSS
MOST OF OUR FORECAST AREA. THE SMOKE IS FORECAST TO REMAIN OVER
THE AREA AT LEAST THROUGH THE NIGHT, BUT THE NIGHT TIME
SETTLING OF THE SMOKE FAVORS A PARTICULARLY SMOKEY SATURDAY
MORNING, INCLUDING THE TREASURE VALLEY.
AVIATION
GENERALLY VFR. HAZE FROM WILDFIRE SMOKE THROUGH
~20KFT MSL, REDUCING TO MVFR VISIBILITY IN SOME AREAS. ISOLATED
SHOWERS/THUNDERSTORMS IN E-CENTRAL OREGON, AND HIGHER TERRAIN
SURROUNDING THE SNAKE PLAIN IN IDAHO AFTER 20Z TODAY. THUNDERSTORMS
CAPABLE OF MODERATE/HEAVY RAINFALL, SMALL HAIL, AND GUSTS TO 30-45
KT. SURFACE WINDS: VARIABLE UP TO 10 KT. WINDS ALOFT AT 10KFT
MSL: VARIABLE 5-10 KT.
KBOI...VFR. HAZE FROM WILDFIRE SMOKE. LIGHT SE SURFACE WINDS,
BECOMING NW IN THE AFTERNOON. A BRIEF 25 KT OUTFLOW GUST FROM
STORMS TO THE FAR NW THIS EVENING IS POSSIBLE.
WEEKEND OUTLOOK...VFR. CONTINUED HAZE FROM WILDFIRE SMOKE.
SURFACE WINDS GENERALLY S-E 5-15 KT.
PREV DISCUSSION
SHORT TERM...TODAY THROUGH SUNDAY NIGHT...FOR TODAY, LINGERING
MID-LEVEL MOISTURE WILL SUPPORT ANOTHER ROUND OF AFTERNOON AND
EVENING THUNDERSTORMS. SIMILAR TO YESTERDAY, STORMS WILL
INITIATE ACROSS SE OREGON AND MOUNTAINOUS AREAS ALONG THE ID/OR
BORDER. ISOLATED STRONGER STORMS ARE POSSIBLE, BRINGING WINDS TO
45 MPH BRIEF HEAVY RAIN AND SMALL HAIL. SATURDAY AND SUNDAY
WILL SEE AN AMPLIFYING UPPER RIDGE BRING DRY AND STABLE
CONDITIONS TO THE REGION, SHUTTING DOWN ANY POTENTIAL FOR
THUNDERSTORM DEVELOPMENT. TEMPERATURES WILL WARM SEVERAL DEGREES
EACH DAY THROUGH SUNDAY, PLACING VALLEYS IN THE LOW 90S AND
MTNS IN THE LOW-MID 80S OVER THE WEEKEND. WESTERLY FLOW WILL
CONTINUE TO TRANSPORT SMOKE FROM WILDFIRES (MOSTLY THE EMIGRANT
FIRE LOCATED SW OF BEND) INTO SE OREGON AND SW IDAHO. COULD SEE
SOME IMPROVEMENT OVER THE WEEKEND AS SOUTHERLY FLOW DEFLECTS
THE THICKER SMOKE TO THE NORTH AND WEST OF OUR AREA.
LONG TERM...MONDAY THROUGH FRIDAY...A HIGH AMPLITUDE RIDGE WILL
REMAIN POSITIONED OVER THE INTERIOR WESTERN US THROUGH MOST OF
NEXT WEEK. SOUTHERLY FLOW ON THE WEST SIDE OF THE RIDGE AND A
MINOR CLOSED LOW ALONG THE CA COAST WILL DRAW MONSOON MOISTURE
NORTHWARD INTO THE REGION TUE/WED. THERE ARE DIFFERING IDEAS
AMONG THE OPERATIONAL SOLUTIONS ON HOW TO HANDLE THESE FEATURES,
BUT INITIAL THOUGHTS WOULD BE THAT SE OREGON AND AREAS ALONG
THE ID/NV BORDER ARE THE MOST LIKELY SPOTS TO SEE A RESULTING
CHANCE OF THUNDERSTORMS. THIS THREAT WOULD POSSIBLY SHIFT INTO
CENTRAL IDAHO FOR WED/THUR, THOUGH CONFIDENCE ON THESE DETAILS
IS LOW. FOR NOW STICKING WITH THE NBM OUTPUT WHICH CARRIES A
10-15% CHANCE IN THESE AREAS STARTING TUESDAY. TEMPERATURES HOLD
AROUND 5 DEGREES ABOVE NORMAL UNDER THE RIDGE, OR HIGHS IN THE
LOW 90S ACROSS LOWER VALLEYS AND MID 80S IN MTN VALLEYS.
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
DISCUSSION...JM
AVIATION.....JM
SHORT TERM...DG
LONG TERM....DG
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