924
FXUS65 KBOI 251600
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1000 AM MDT MON AUG 25 2025
DISCUSSION
SHOWERS ARE ONGOING ACROSS MUCH OF THE AREA THIS
MORNING AS A SURGE OF MONSOONAL MOISTURE CONTINUES TO LIFT
NORTH. THE HEAVIEST RAINFALL SO FAR HAS BEEN OVER SOUTH-CENTRAL
IDAHO, WHERE TOTALS HAVE REACHED AT LEAST A TENTH OF AN INCH.
SATELLITE IMAGERY EARLY THIS MORNING SHOWED A WEAK SHORTWAVE
OVER NORTHWEST NEVADA. AS THIS FEATURE LIFTS EAST-NORTHEAST
TODAY, IT WILL PROMOTE SOME PARTIAL CLEARING ALONG THE NEVADA
BORDER, ALLOWING FOR THUNDERSTORM DEVELOPMENT LATER THIS
AFTERNOON AND EVENING. STORMS ARE EXPECTED TO SPREAD GRADUALLY
NORTHWARD INTO THE WESTERN MAGIC VALLEY AND CENTRAL IDAHO
MOUNTAINS, WITH HEAVY RAINFALL POSSIBLE AS PRECIPITABLE WATER
VALUES APPROACH THE 95TH PERCENTILE.
MOISTURE WILL CONTINUE TO DEEPEN ACROSS THE REGION THROUGH
WEDNESDAY, BRINGING INCREASING COVERAGE OF SHOWERS AND
THUNDERSTORMS. THE PRIMARY CONCERN WILL BE EXCESSIVE RAINFALL,
ESPECIALLY ON WEDNESDAY WHEN THE BEST INSTABILITY OVERLAPS WITH
A SLOW-MOVING UPPER TROUGH. A HYDROLOGIC OUTLOOK IS IN EFFECT
FOR THIS THREAT, AND FLASH FLOOD WATCHES WILL LIKELY BE ISSUED
IN THE NEAR TERM.
AVIATION
AREAS OF MVFR TO LIFR VISIBILITY FROM SMOKE IN W-CENTRAL
ID AND RAIN THROUGHOUT THE AREA. LIGHT-MODERATE RAINS CONTINUE
THROUGH THE FORECAST, WITH ISOLATED THUNDERSTORMS THIS AFTERNOON.
THUNDERSTORMS COULD PRODUCE GUSTY OUTFLOW WINDS AND LOCALLY HEAVY
RAINFALL. SURFACE WINDS: N-NW 5-15 KT, WITH OUTFLOW GUSTS UP TO 45
KT. WINDS ALOFT AT 10KFT MSL: VARIABLE 5-15 KT.
KBOI...VFR. LIGHT SMOKE LAYERS DEGRADING VISIBILITY. LIGHT SHOWERS
AND VIRGA THROUGHOUT THE DAY, WITH A 10% CHANCE OF THUNDER THIS
EVENING. ERRATIC GUSTY WINDS FROM DISTANT STORMS WILL BE POSSIBLE
WITH SPEEDS NEAR 40-45 KT. SURFACE WINDS: VARIABLE 5-15 KT, BUT
GENERALLY OUT OF THE S-E.
PREV DISCUSSION
SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...THE MONSOON SURGE
CONTINUES ITS NORTHWARD PROGRESSION, AS EVIDENCED BY THE
WIDESPREAD CLOUDINESS AND LIGHT SHOWER ACTIVITY EARLY THIS
MORNING. THE MONSOON MOISTURE WILL CONTINUE TO SPREAD NORTHWARD
THROUGH WEDNESDAY, LEADING TO INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS. THE MAIN CONCERN WITH THE THUNDERSTORMS WILL BE
THE POTENTIAL FOR EXCESSIVE RAINFALL. THERE IS A MARGINAL RISK
FOR THESE HEAVY RAINFALL PRODUCING THUNDERSTORMS, STARTING
ACROSS SOUTHERN AREAS TODAY AND EXPANDING NORTHWARD THROUGH
WEDNESDAY. THE GREATEST THREAT APPEARS TO BE ON WEDNESDAY AS
THE BEST INSTABILITY COINCIDES WITH THE PASSING OF A SLOW-MOVING
UPPER TROUGH. THE UNKNOWN IS WHETHER THERE WILL BE ENOUGH
CLEARING FOR DAYTIME HEATING TO ACT ON THE HIGH MOISTURE LADEN
ATMOSPHERE, BUT EVEN SLIGHT CLEARING COULD GIVE RISE TO
THUNDERSTORMS WITH VERY HEAVY RAINFALL. A HYDROLOGIC OUTLOOK
HAS BEEN ISSUED TO ADDRESS THIS CONCERN, WITH THE POSSIBILITY OF
FLASH FLOOD WATCHES BEING ISSUED IN THE FUTURE. TEMPERATURES
CONTINUE ON A DOWNWARD TREND, WITH HIGHS ON WEDNESDAY STRUGGLING
TO EVEN REACH 80F IN THE VALLEYS.
LONG TERM...THURSDAY THROUGH MONDAY...THE MONSOON MOISTURE
LINGERS ON THURSDAY, ESPECIALLY ON SW IDAHO WHERE THERE IS A
30-60 PERCENT CHANCE OF SHOWERS AND THUNDERSTORMS, WHILE DRIER
AIR STARTS TO WORK INTO SE OREGON. THE MODELS ARE IN EXCELLENT
AGREEMENT WITH THE DEVELOPMENT OF AN UPPER RIDGE ON FRIDAY THAT
PERSISTS INTO EARLY NEXT WEEK FOR DRY CONDITIONS AND A WARMING
TREND AS TEMPERATURES RETURN TO A FEW DEGREES ABOVE NORMAL.
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...JDS
AVIATION.....JM
SHORT TERM...BW
LONG TERM....BW
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page