167
FXUS65 KBOI 290905
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
305 AM MDT Mon Apr 29 2024

.SHORT TERM...Today through Wednesday night...An upper level
trough will move through the region today, bringing a cold front
through the area. This front will bring much colder
temperatures, gusty westerly winds, and showers. The front looks
to move through southeast Oregon by early afternoon, and then
through southwest Idaho by late afternoon. The best chance for
showers will be over the higher terrain in Baker County, OR,
near the ID-NV border, and the West Central Mountains (70-80%
chance). However, there is also a low chance (10-20% chance) for
showers over the Treasure Valley on Monday afternoon. Models
show the best instability and heaviest showers over the Central
ID Mountains and Baker County, OR, but there is still sufficient
instability across the region that would allow for a stray
thunderstorm near the NV border and over the Lower Snake
Plain. Confidence is low, but it has been added to the forecast
for this afternoon. Winds will be highest in the Lower Snake
River Plain today and tomorrow afternoon, but hi-res models have
trended winds down quite a bit since last night. Winds will
still be gusty, especially during the frontal passage today, so
the wind advisory remains in effect for those zones.

The colder air mass will lower snow levels quite a bit later
today, especially across the northern portions of our CWA. The
West Central/Boise Mountains and Baker County will see snow
levels lower to 3000-4000 feet overnight, so any precipitation
by the evening and overnight will fall as snow. Limited moisture
will reduce accumulations, but an inch or two is possible over
the higher terrain by early Tuesday morning.

As the low exits to the east, a weak ridge will build into the
region on Wednesday, bringing warmer and drier conditions.
Temperatures will still be about 5-10 degrees below normal today
through Tuesday, but the ridge will usher in a warming trend
for the end of the short term period.

LONG TERM...Thursday through Monday...Latest models are in poor
agreement, especially next weekend, leading to substantial
uncertainty in the forecast. There are two main features of
interest. The first is a compact low pressure system that is progged
to move through from the northwest Thursday into Friday. The track
of the low differs among the models...some are slower and direct
more showers to the area, while others are faster or show the bulk
of the showers to our north. Most of the members favor a more
northerly track, resulting in a 15-30 percent chance of showers
across Baker County and central Idaho Thursday and Friday. Breezy
conditions are expected both days, along with near-normal
temperatures. The second feature of interest is another Pacific low
that is either progged to move through our area over the weekend, or
remain near the west coast. Therefore, there is a 10-20 degree
spread in temperatures. The ensemble blend favors a warmer/wetter
solution with temperatures several degrees above normal while
maintaining a 15-40 percent chance of showers over the weekend and
into early next week.

&&

.AVIATION...VFR. Scattered MVFR showers across the north (KBKE-KMYL)
through 29/18Z, becoming widespread in the north and isolated to
scattered elsewhere after 29/18Z. Mountains obscured. Snow levels
5500-6500 ft MSL, lowering to 4000-5500 ft by 29/18Z. Surface winds:
W-NW 5-15 kt, increasing to 15-25 kt with gusts up to 40 kt after
29/18Z. Winds aloft at 10kft MSL: W-SW 15-30 kt.

KBOI...VFR with increasing and lowering clouds. Slight chance (less
than 20 percent) of -SHRA after 29/18Z. Surface winds: SE up to 10
kt, shifting to the NW after 29/12Z and increasing to 12-17 kt with
gusts to near 30 kt by 29/18Z.


&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory from noon today to 7 PM MDT this evening
     IDZ014-016-028.
OR...None.

&&

$$

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SHORT TERM...SA
LONG TERM....BW
AVIATION.....BW