Sunnyslope, Idaho Weather Forecast Discussion

532
FXUS65 KBOI 200238
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
838 PM MDT Fri Sep 19 2025
.DISCUSSION...A low-pressure system over central California
continues to track eastward, resulting in high clouds across
much of the forecast area this evening. Virga showers persist
along the Idaho-Nevada border and are expected to dissipate by
midnight, with no lightning observed so far. For Saturday, high
clouds will decrease, allowing for greater daytime heating and
increased instability. This will lead to a slightly higher
chance of thunderstorms, which will generally develop south of
the Snake River Plain over higher terrain. A few storms may also
develop over the mountains of Baker County. The stronger storms
could produce gusty outflow winds up to 45 mph. The current
forecast handles this well, so no updates are needed at this
time.
&&
.AVIATION...VFR and scattered clouds. Isolated showers along
and south of the Nevada border this evening not expected to
impact terminals. Surface winds: variable up to 10 kt. Winds
aloft at 10kft MSL: S-E 5-10 kt.
KBOI...VFR with high clouds. Surface winds NW 5-10 kt with some
variability, becoming SE after sunset.
Weekend Outlook...VFR with increasing chances for showers
and thunderstorms beginning Saturday afternoon, mainly south of
the Snake River Plain. By Sunday afternoon showers and
thunderstorms will be possible over the mountains of central
Idaho and northeast Oregon. MVFR will be possible in the
strongest storms along with gusty frontal winds. Surface winds
SW 5- 10 kt on Saturday increasing to NW 10-20 kt on Sunday.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Sunday night...A low pressure
system remains over central CA today with high clouds moving
from the Great Basin northward into southeast OR and southwest
ID. Some cumulus buildups present over southern Owyhee County
this afternoon will be the focus of isolated thunderstorms this
afternoon and evening. High clouds on Saturday decrease,
allowing for more daytime heating and instability with a
slightly higher chance for storms. Storms will generally develop
south of the Snake Plain over the higher terrain on Saturday
afternoon. A trough from the Gulf of Alaska will bring a cold
front to the area on Sunday, which will interact with the
moisture already in place. Scattered showers and isolated
thunderstorms form early Sunday morning ahead of the front, and
intensify with the daytime heating on Sunday afternoon as the
front moves east. The front will bring breezy west-northwest
winds during the afternoon Sunday.
LONG TERM...Monday through Friday...After Sunday`s cold front
and trough, Monday will be a few degrees below normal and a
little breezy. However, high pressure quickly builds in
overhead, supporting a warming trend through Thursday. Winds
remain typical, but temps warm up to 10 degrees above normal by
Thursday. Models diverge on the track of a closed upper low over
California, so the forecast for Friday becomes a little
uncertain. The average solution has the closed low clipping the
area, with a 10-20% chance of precipitation a slight cool down
and mild breezes.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
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DISCUSSION...JDS
AVIATION.....JDS
SHORT TERM...KA
LONG TERM....JM

NWS BOI Office Area Forecast Discussion