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000
FXUS65 KBOI 151557
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
957 AM MDT Mon Apr 15 2024

.DISCUSSION...A area of low pressure in eastern Idaho and high
pressure off the coast will enhance the winds today, becoming
very windy in southern Idaho (east of Boise) where a Wind
Advisory is in effect this afternoon and evening. The bulk of
showers associated with an upper low will remain mainly to our
east, but isolated light showers or sprinkles are expected over
SW Idaho today. Forecast was updated to expand the isolated
showers into the Treasure Valley this morning.

&&

.AVIATION...Mainly VFR. Isolated to scattered showers today,
mainly over central Idaho, with MVFR/IFR and terrain obscuration
in/around showers. Snow levels 6500-8000 ft MSL. Surface winds:
becoming W-NW 10-20 kt with gusts to 30 kt, except 25-35 kt
with gusts up to 45 kt near KMUO/KGNG/KJER/KTWF. Winds aloft at
10kft MSL: N-NW 10-20 kt, increasing to 20-40 kt by 18Z/Mon.

KBOI...VFR. Broken clouds this morning, becoming scattered
after 18Z. Isolated rain showers through 17Z this morning, but
only light precipitation anticipated. Surface winds W-NW 5-10kt,
becoming NW 10-20 kt with gusts to 30 kt after 17Z, then W-NW
less than 10kt after 02Z.

&&

.HYDROLOGY...The Owyhee River below Owyhee Dam is expected to
remain above minor flood stage through at least Friday.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Wednesday night...Isolated showers
persist in southeast Oregon and the West Central mountains of
Idaho as a low-pressure system exits the region this morning.
As this system consolidates over Utah, it will strengthen the
surface pressure gradient across our forecast area, leading to
windy conditions today.

The strongest winds are forecasted for the lower valleys,
stretching from Baker City through the Western Magic Valley.
There`s a 60%-70% chance of wind gusts surpassing 50 MPH from
Mountain Home through the Western Magic Valley this afternoon,
according to probabilistic data. While the EFI is less certain
about higher winds, it does highlight the Western Magic Valley
as having the greatest potential. Recent guidance also indicates
elevated winds for the Southwest Highlands and Camas Prairie,
prompting the inclusion of these areas in today`s wind advisory.
Expect temperatures to decrease as cold air aloft moves in,
hitting near normal.

The pressure gradient is expected to persist into Tuesday,
coinciding with the arrival of a cold core low-pressure system
and accompanying cold front from the north. This front will
sweep across the region late Tuesday into early Wednesday,
though moisture along the front is limited, resulting in only a
slight chance of snow showers in the West Central Mountains.
Tuesday`s temperatures are projected to dip approximately 2
degrees below normal, with Wednesday likely seeing the coldest
air aloft for the week. Breezy northwest winds will persist as
the pressure gradient lingers, driving temperatures to fall 5 to
8 degrees below normal.

Thursday morning is forecasted to be particularly chilly, with
temperatures at or below freezing in the lower valleys. Current
probabilistic data indicates a 30-50% chance of temperatures
dropping below 32 degrees in the western Snake River plain.

LONG TERM...Thursday through Monday...Cool, northwest flow
will continue along the backside of a broad trough over the
northern U.S. for Thursday. A 10-20% chance of showers is
currently forecast for west-central Idaho, while the rest of the
area is favored to remain dry. Beginning Friday, a weak ridge
will build as the trough exits toward the east. Temperatures
will trend a few degrees warmer each day through the weekend,
with mostly dry conditions anticipated. Meanwhile, model members
suggest a quick-moving shortwave trough will arrive in the
Pacific Northwest by late in the weekend. This trough is
currently forecast to remain farther north along the Canadian
border, bringing only a slight chance (15-20%) of showers for
west-central Idaho late Saturday and Sunday. Uncertainty remains
on the track, strength, and timing of this trough, which will
affect the temperatures and shower extent for the weekend and
Monday.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory until midnight MDT tonight IDZ014>016-028-030.
OR...None.

&&

$$

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DISCUSSION...BW
AVIATION.....MC
HYDROLOGY....BW
SHORT TERM...JDS
LONG TERM....SH