839
FXUS65 KBOI 111520
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
920 AM MDT Tue Jun 11 2024

.DISCUSSION...Sunny and 6-8 degrees warmer today as an upper
ridge moves through, then about 5 degrees cooler Wednesday as a
weak north Pacific upper trough moves past to our north. Hot
again Thursday under an upper ridge before a deep Gulf of Alaska
upper trough comes fully inland over the weekend and Monday.
The trough will bring much cooler temps behind a cold front
Friday, with deterministic GFS and ECM even cooler than NBM and
our current forecast. Current forecast has highs in the 60s to
lower 70s Sunday and Monday. Deterministic models look about 5
degrees cooler. Models keep most pcpn north of our CWA when the
trough gets here, except a 20-30 percent chance of showers in
northern mountains. Strong westerly flow aloft also supports
increased wind Friday through Sunday, already in our forecast.
No updates.

&&

.AVIATION...VFR and clear. Surface winds: variable less than 10 kt
until 20Z, then W-NW 5-15 kt. Winds aloft at 10kft: W-SW 15-25
kt.

KBOI...VFR. Surface winds: variable less than 5 kt through 20Z, then
NW 7-13 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Thursday night...A very weak ridge
axis will pass overhead today, giving us mostly clear skies and
temperatures around 15 degrees above normal. As the ridge
departs to the east, it will be followed by a trough passing by
to our north tonight. This trough will push a dry cold front
through the region, resulting in stronger-than-normal NW winds
from the Baker Valley (gusts 25-35 mph) through the Treasure
Valley (gusts 20-30 mph) and into the western Magic Valley
(gusts 20-30 mph). Wed will remain dry and not as hot as our
upper flow comes out of the WSW, but gusts 20-30 mph will
continue from east of Boise through the western Magic Valley.

A deep and strong upper level closed low will move toward the
western coast of Canada Thursday, turning our flow more
southwesterly. This will advect warmer air into the region, with
highs 10 to 15 degrees above normal.

LONG TERM...Friday through Tuesday...A weak dry cold front
will move through early Friday, bringing temps down just a few
degrees, but still 5-10 degrees above normal. Models continue
to agree that the upper low will move east over the weekend,
sending an initial shortwave trough eastward across northern
Idaho Saturday. However, they show different depictions of how
the remaining energy will evolve and move. For now, it appears
we should be dry through early Sunday, with low chances (15-25%)
for showers in the West Central Mountains late Sunday into
Sunday night. And with the uncertainty in the progression of
the upper level energy Monday into Tuesday, it seems wise to
continue low chances through the remainder of the long term
period. Temperatures will be considerably cooler Saturday
through Tuesday, with Sun/Mon having a good chance of being
below normal. This will likely end approximately 2 straight
weeks of above-normal temperatures over the region.

&&

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

&&

$$

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DISCUSSION...LC
AVIATION.....ST
SHORT TERM...SP
LONG TERM....SP