000
FXUS65 KBOI 240245
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
845 PM MDT Tue Apr 23 2024

.DISCUSSION...A few high based virga showers are moving across
southern Malheur County and western Baker County in Oregon this
evening. Most of the precipitation is evaporating before it hits
the ground due to a dry surface layer. A stray outflow boundary
is possible from a stronger shower early tonight, but confidence
is low. Warmer temperatures are anticpated tonight through
tomorrow ahead of the frontal passage tomorrow night. The
current forecast covers this well, so no updates are necessary.

&&

.AVIATION...VFR. Increasing mid-level clouds with virga showers
overnight near the NV border, then isolated showers and a
slight chance of thunderstorms developing over SE OR and SW ID
after Wed/16Z. Gusty and erratic winds up to 40 kt near
thunderstorms. Surface winds: variable 10 kt or less, then W-NW
10-15 kt with gusts to 20 kt after Wed/21Z. Winds aloft at 10kft
MSL: SW-NW 10-20 kt.

KBOI...VFR. Isolated showers on Wednesday morning, mainly NW of
terminal. Surface winds: variable 6 kt or less overnight, then
N-NW 8-12 kt after Wed/18Z.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Thursday night...Southwest flow
aloft continues to bring warmer air into the region, with about
10 degrees of warming compared to yesterday. Some cumulus fields
present on visible satellite this afternoon southwest of Steens
Mountain OR will be the focus of showers and thunderstorms
later this evening. Some storms will be capable of producing
wind gusts up to 40 mph, mainly across southern Harney and
Malheur Counties. CAM models have these storms transitioning
into showers later tonight, and tracking NE into southwest ID,
where have added a chance of sprinkles on Wednesday morning.
Southwest flow will continue to bring more moisture to the area
and shower and thunderstorm coverage will be higher on
Wednesday afternoon. The thunderstorms will be capable of
producing gusty winds up to 40 mph on Wednesday afternoon. The
trough exits to the east on Thursday as another Pacific trough
takes aim on the Northwest. This system is more organized and
shows better potential for showers to spread into the area by
Thursday night, especially in the higher elevations. The system
will also be accompanied by a cold front, resulting in breezy to
locally windy conditions on Thursday. Warmer temperatures are
expected today and Wednesday, averaging 5 to 10 degrees above
normal, then cooling several degrees on Thursday with the
arrival of the cold front.

LONG TERM...Friday through Tuesday...An upper level trough
will move across our area on Friday, bringing showers and cooler
temperatures. Precipitation chances will rise to 40-90%, and
cold temperatures aloft combined with strong surface heating
will result in a slight chance of afternoon thunderstorms.
Highs drop to 3-5 degrees below normal on Friday and Saturday.
The trough will move east over the weekend as an unseasonably
deep upper level low moves across the Gulf of Alaska. Forecast
confidence beyond Sunday is low, as the handling of the trough
in the Gulf of Alaska is quite different between the ensemble
suites. Right now our area is on the interface between
temperatures 10-15 degrees below normal and 10-15 degrees above
normal depending on where the system tracks. Much cooler
temperatures and lower snow levels are possible next week if the
center of the trough off the coast moves inland, and much warmer
conditions if the trough stays west of the area.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.

&&

$$

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DISCUSSION...SA
AVIATION.....SA
SHORT TERM...KA
LONG TERM....KA