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470
FXUS65 KBOI 231526
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
926 AM MDT Thu May 23 2024

.DISCUSSION...
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Yesterday`s upper low in Idaho was in northern
Wyoming this morning leaving behind clearing skies, breezy
west/northwest winds, and cool temps in our CWA today. After
brief ridging aloft and warmer temps Friday, the next upper
trough will come in from the BC coast Friday night and Saturday
with showers, and cooler temps again Saturday. That trough looks
weaker than yesterday`s trough so showers should be lighter and
mainly in northern areas. SPC forecasts a slight chance (20%)
of thunderstorms Saturday in Idaho but not in Oregon. Current
forecast looks good on all this. No updates.
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&&

.AVIATION...
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VFR. Decreasing clouds. Surface winds: W to NW
5-15 kt, except 10-20 kt with gusts to 30 kt for KMUO/KJER/KTWF
through 23/23Z. Winds aloft at 10k ft MSL: NW-N 15-25 kt,
becoming variable 10 kt or less by 24/00Z.

KBOI...VFR. NW winds 5-15 kt, then SE 5-10 kt after sunset.

Weekend Outlook...Mostly VFR. A chance (20-40%) of showers
beginning Friday evening in E Oregon. Increasing chance
(25-50%) of showers on Saturday as system moves into SW Idaho.
Potential for aft/eve thunderstorms both days. MVFR/IFR possible
in precip, along with mountain obscuration. Snow levels
6500-7500 ft MSL. Surface winds E-SE 5-15 kt Friday, then W-NW
10-20 kt with gusts to 25-30 kt Saturday. VFR Sunday with winds
W-NW 5-15 kt.
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&&

.PREV DISCUSSION...
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SHORT TERM...Today through Saturday night...The center of an
upper level low is currently spinning over southern Idaho,
bringing wrap-around moisture into central Idaho and northeast
Oregon through the morning. Snow levels are around 4500 ft MSL
and will rise this afternoon to 6000-6500 ft. As a result, snow
will fall as low as 4500 ft MSL for these areas this morning,
with only light additional accumulations expected. The low will
begin to exit toward the east by late morning, allowing drier
northwesterly flow to dominate the rest of today. Breezy to
windy surface winds will develop behind the low through the
afternoon, mainly for the western Snake Plain and adjacent
terrain. Temperatures will be slightly warmer today than
Wednesday, but will remain around 10 degrees below normal.

Dry conditions with near-seasonable temperatures will return for
Friday ahead of the next weak trough to arrive late Friday. A
chance of showers will begin Friday evening (20-40%) and spread
from west to east through Saturday (25-50%). A slight chance of
afternoon/evening thunderstorms are forecast in east Oregon
Friday, and into southwest Idaho on Saturday. Winds are expected
to increase on Saturday, with temperatures dropping 5-10
degrees below normal once again.

LONG TERM...Sunday through Thursday...Sunny skies with above
normal high temperatures are anticipated across the region as a
dry, stable, zonal flow pattern temporary sets up. With this
abundance of unfettered insulation, high temperatures will rise
to around ten degrees above normal - mid 80`s in most places.
The Magic Valley and nearby southern mountainous areas can also
expect breezy west winds on Sunday with southern Harney County
seeing these same breezy conditions beginning late Tuesday -
both associated with tighter pressure gradients. The fair
weather conditions across the region will last until Wednesday
where a North Pacific trough will near and breach Eastern
Oregon, ushering in a more moist, unstable airmass. This new air
mass will begin to take control and affect the extreme northern
portions forecast area - setting up (for now) low probabilistic
chances (10-20%) for showers.
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&&

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

&&

$$

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DISCUSSION...LC
AVIATION.....SP
SHORT TERM...SH
LONG TERM....WH