Knowlton Heights, Idaho Weather Forecast Discussion

582
FXUS65 KBOI 092048
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
248 PM MDT Tue Sep 9 2025
.SHORT TERM...Tonight through Thursday night...Active weather is
expected through the short term. This will be the result of an
upper level low currently centered over far northern California
that will slowly drift east through Thursday. The low will be
accompanied by abundant moisture with precipitable water values
rising to the 80th to 90th percentile. Ahead of this low,
showers and isolated thunderstorms will develop over the central
ID mountains this evening before tapering off. Isolated
activity will continue overnight across the area as a shortwave
lifts north.
On Wednesday, shower and thunderstorm coverage will expand with
daytime heating. Models are depicting two primary areas of
development. The first will be near the low center across
central Oregon, where cooler temperatures will allow for
widespread showers and embedded thunderstorms capable of heavy
rainfall. The second area is expected to develop across far SE
Oregon and SW Idaho late afternoon and evening as an embedded
shortwave rotates around the main upper low into our area and
provides lift for more organized development. Partial clearing
is expected during the afternoon tomorrow in this area allowing
for warm surface temperatures and increasing instability. Enough
shear will also be present for stronger storms to develop with
heavy rain, hail, and gusty winds in excess of 50 mph possible.
Heavy rain over recent burn scars may also create potential for
flash flooding and debris flows, although confidence in this is
low.
Showers and thunderstorms will continue over our area Wednesday
night and Thursday as the low slowly moves overhead. The focus
for significant precipitation should be near the low center
across SE Oregon, as well as the mountains of SW Idaho. This
will also cool temperatures to 5-10 degrees below normal.
Precipitation chances will diminish Thursday night with the loss
of daytime heating.
.LONG TERM...Friday through Tuesday...The pattern will remain
active through the extended period. The upper low will continue
to slowly drift across our area on Friday and weaken. This will
bring a 40-70% chance of showers and embedded thunderstorms
Friday afternoon, aided by daytime heating. Shower chances will
decrease on Saturday, with most activity in the mountains. An
upper level ridge will briefly move overhead Saturday night
before the next upper level low moves into the Pacific Northwest
on Sunday. This will bring a 30-50% chance of showers and
slight chance of thunderstorms Sunday and Monday, then decrease
on Tuesday as the low moves east. This pattern will keep
temperatures near to slightly below normal through the period.
&&
.AVIATION...Mainly VFR. Showers and thunderstorms will continue
through the evening in the central ID mtns, primarily east of
KMYL. Gusty outflow winds with stronger storms up to 40 kts and
mountain obscuration in precipitation, along with small hail
possible. Additional showers and isolated thunderstorms moving
through overnight into Wednesday morning, followed by more
widespread development in the afternoon and evening. Storms may
produce gusty winds, heavy rain, and hail. Surface winds:
variable less than 10 kt. Winds aloft at 10kft MSL: S-SW 5-15
kt.
KBOI...VFR under mid to high clouds. A 10% chance of showers
and thunderstorms this afternoon. Light rain showers moving
through overnight. Winds NW 4-8 kt, becoming variable overnight.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
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SHORT TERM...ST
LONG TERM....ST
AVIATION.....ST

NWS BOI Office Area Forecast Discussion