493
FXUS65 KBOI 111947
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
147 PM MDT THU SEP 11 2025
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
CONVECTION HAS
ALREADY BEGUN TODAY, WITH SCATTERED LIGHT SHOWERS AND
THUNDERSTORMS EXPECTED TO BECOME NUMEROUS LATER THIS AFTERNOON
TROUGH THIS EVENING. RAIN RATES WILL INCREASE, WITH STRONGER
STORMS CAPABLE OF HEAVY RAINFALL, SMALL HAIL, AND OUTFLOW GUSTS
UP TO 45 MPH. A SLIGHT DEVIATION IN THE LOW HAS SHIFTED OUR AREA
OF BURN SCAR FLASH FLOODING CONCERN FROM OREGON TO CENTRAL
IDAHO. WHILE BURN SCARS IN OREGON WILL STILL RECEIVE SOME RAIN,
THE BULK OF THE MOISTURE SEEMS TO BE PASSING NORTH NOW. IN
IDAHO, THE CHANGE HAS MOVED MOISTURE OVER VERY REACTIVE BURN
SCARS, WITH CONVECTION ALREADY OVER AREAS INCLUDING THE WAPITI
BURN SCAR, SO THE FLASH FLOOD WATCH HAS BEEN MOVED TO CENTRAL
IDAHO.
CHANCES OF PRECIPITATION ACROSS THE AREA OUTSIDE OF AREAS
PREVIOUSLY MENTIONED VARY GREATLY FROM 20% TO 50%, GENERALLY
DECREASING THE CLOSER YOU GET TO THE CENTER OF THE LOW WHICH IS
PROJECTED TO MOVE OVER THE TREASURE VALLEY AND LOWER SNAKE
PLAIN. HEAVY RAIN WILL BE MOSTLY LIMITED TO EASTERN OREGON AND
CENTRAL IDAHO MOUNTAINS. PRECIPITATION BEGINS TO TAPER OFF AFTER
ABOUT 9PM MDT THROUGH MIDNIGHT. OVERNIGHT, LIGHT SHOWERS MAY
CONTINUE ACROSS NORTHERN PORTIONS OF OUR FORECAST AREA, BEFORE
SCATTERED SHOWERS AND ISOLATED STORMS FORM ACROSS BAKER AND
VALLEY COUNTIES, AS WELL AS THE NV BORDER. AS THE LOW EXITS
EASTWARD FRIDAY NIGHT, CONDITIONS WARM AND DRY AS A SHORTWAVE
RIDGE MOVES IN FOR THE WEEKEND, BRINGING TEMPS BACK TO NEAR
NORMAL.
LONG TERM...SUNDAY THROUGH THURSDAY
AN UPPER LEVEL TROUGH
WILL MOVE THROUGH THE PACIFIC NORTHWEST ON SUNDAY. THE BOTTOM
PORTION OF THE TROUGH WILL BRING A POCKET OF MOISTURE AND A
20-50% CHANCE OF SHOWERS/STORMS TO THE AREA, WITH THE GREATEST
CHANCE IN MOUNTAINS. AS IT EXITS TO THE EAST ON MONDAY EVENING,
SHOWERS AND STORMS CONTINUE TO BE POSSIBLE IN CENTRAL ID. THE
RELATED COLD FRONT WILL ALSO BRING BREEZY WINDS AND COOLER
TEMPERATURES ON MONDAY. TUESDAY THROUGH THURSDAY A RIDGE BEGINS
TO AMPLIFY, WARMING TEMPS AND CLEARING SKIES. MODELS DIVERGE
AFTER THURSDAY, BUT DETERMINISTIC MODELS SHOW A DEEP TROUGH
MOVING CLOSE TO THE PACNW AND CANADIAN WEST COASTS. ENSEMBLE
MEANS PROJECT IT STEADILY MOVING INLAND, WHICH WOULD BRING A DAY
OR TWO PRECIPITATION, A COLD FRONT AND BREEZY WINDS. AFTER THE
5-10 DEGREE BELOW NORMAL DAY ON MONDAY, TEMPS WARM BACK UP TO A
FEW DEGREES ABOVE NORMAL THROUGH THE WEEK.
AVIATION
NUMEROUS SHOWERS AND SCATTERS THUNDERSTORMS IN SE OR
AND CENTRAL ID. SCATTERED SHOWERS AND ISOLATED STORMS ACROSS THE
REST OF THE AREA THIS AFTERNOON AND EVENING. STORMS MAY PRODUCE
HEAVY RAIN, SMALL HAIL, AND GUSTY OUTFLOWS TO 40 KT. STORMS
WILL RESULT IN BRIEF MVFR/IFR CONDITIONS. PATCHY FOG IS EXPECTED
IN MOUNTAIN VALLEYS AND HIGHLAND BASINS TONIGHT, ESPECIALLY
KMYL. SURFACE WINDS: MAINLY SW-NW 5-15 KT, BECOMING LIGHT AND
VARIABLE AFTER SUNSET. WINDS ALOFT AT 10KFT MSL: VARIABLE UP TO
10 KT.
KBOI...VFR. SCATTERED-BROKEN MID LEVEL CLOUDS TODAY WITH ISOLATED
SHOWERS THAT MAY DRIFT INTO THE VICINITY THIS AFTERNOON.
SURFACE WINDS: NW 5-10 KT.
WEEKEND OUTLOOK...SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP
FRIDAY AFTERNOON, MAINLY OVER THE HIGHER TERRAIN, RESULTING IN
LOCALIZED MVFR/IFR CONDITIONS AND MOUNTAIN OBSCURATION. DRIER
CONDITIONS WILL RETURN SATURDAY BEFORE SHOWER AND THUNDERSTORM
CHANCES RETURN ON SUNDAY. SURFACE WINDS MAINLY SW-NW 5-15 KT.
BOI WATCHES/WARNINGS/ADVISORIES
ID...FLASH FLOOD WATCH UNTIL 9 PM MDT THIS EVENING IDZ011-013.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
SHORT TERM...JM
LONG TERM....JM
AVIATION.....JM
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