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000
FXUS65 KBOI 180903
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
303 AM MDT Thu Apr 18 2024

.SHORT TERM...Today through Saturday night...Warmer through
Saturday as yesterday`s upper trough exits east and a low-
amplitude Pacific upper ridge comes inland. The ridge will
pass over our CWA Saturday while a faster-moving upper trough
and surface cold front move onto the northwest coast.
Increasing east-west surface pressure gradient ahead of the
approaching cold front will help raise max temps in our CWA
to the 60s and lower 70s Saturday. Very dry air today and
Friday will begin to moisten Saturday with enough for a 20-40
percent chance of rain showers over Baker County and the west-
central Idaho Mountains Saturday night. Southern areas will
have only clouds at that time. High temperatures will increase
4 to 8 degrees each day through Saturday, but lows will warm
more slowly as dry air, clear skies, and light winds continue
to allow strong radiational cooling at night. Friday morning
will still have a 40-60 percent chance of dropping to 32F or
lower in the Treasure Valley, and greater than 60 percent chance
in the western Magic Valley. Saturday morning will be warmer
with less than 10 percent chance of 32F or lower.

.LONG TERM...Sunday through Thursday...A weak trough will pass
to the north of the forecast area through Sunday. This will
bring a chance (15-30%) of showers to the Baker County and
w-central Idaho mountains through Sunday afternoon. Cooler
temperatures with breezy west-northwest winds will also develop
Sunday afternoon as the trough moves through. Weak high pressure
is expected to return Monday and Tuesday, with temperatures
warming back to 5-10 degrees above normal. There is currently
a 35-55% chance of hitting 80 degrees in the Treasure and Magic
Valleys by Tuesday afternoon. Thereafter, models suggest the
next low pressure system will arrive along the west coast
Wednesday, promoting a chance (20-40%) of showers to the area
as moisture increases ahead of it.

&&

.AVIATION...VFR with passing high clouds this afternoon.
Surface winds: variable 10 kt or less, then generally E-SE
5-15 kt by 18/16Z. Winds aloft at 10kft MSL: variable 5-15 kt.

KBOI...VFR and clear this morning, then passing high clouds
this afternoon. Winds SE 5-15 kt, becoming N-NW or variable
4-7 kt at 19/00Z.

Weekend Outlook...VFR and high clouds Friday and Saturday.
Clouds lowering Saturday evening into Sunday, with scattered
MVFR showers and mountain obscuration developing in the Baker
County and west- central ID mountains. Improvement by Sunday
evening. Snow levels generally 6000-7500 ft MSL during showers.
Surface winds: variable 10 kt or less Friday, SW-SE 5-15 kt
Saturday, and W-NW 10-25 kt Sunday.

&&

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

&&

$$

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SHORT TERM...LC
LONG TERM....SH
AVIATION.....SH