920
FXUS65 KBOI 122039
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
239 PM MDT Wed Jun 12 2024

.SHORT TERM...Tonight through Friday night...Little change from
previous forecast. Hotter Thursday as an upper ridge moves in
from the west. Significant cooling beginning Friday as a deep
upper trough in the Gulf of Alaska moves onto the northwest
coast. Friday looks 6-10 degrees cooler than Thursday, and
Friday night 6-10 degrees cooler than Thursday night (and
even cooler after that). Models show limited moisture but
enough instability for a slight chance of thunderstorms in
Twin Falls County late Thursday/Thursday evening. Light winds
tonight and most of Thursday, then westerly 20 to 30 mph in
Harney County/OR Thursday afternoon and evening, and in
southern Idaho Friday afternoon behind a surface cold front.


.LONG TERM...Saturday through Wednesday...An active pattern
will develop over the extended period, offering a break from
summer heat and a brief return to more springlike conditions.
The core of an upper level trough will move by to our north
Saturday into early Sunday, bringing a dry cold front with much
cooler temperatures and breezy winds. Any chance (10-20%) for
showers will be limited to the northern mountains. Highs on
Saturday will be 10-15 degrees cooler than Friday with another
5 degrees cooling on Sunday. This will place lower valley highs
in the upper 60s to near 70 on Sunday, which is 10-15 degrees
below normal. Models continue to show a closed low moving
through the Pacific Northwest and Northern Rockies Sunday
through Tuesday. The exact track of this low will have a major
impact on our weather, with a more southerly track bringing the
potential for widespread rain (and high-elevation snow above
7000 feet MSL in the central Idaho mountains) and temperatures
15-25 degrees below normal. This southerly track is depicted
by roughly half of the EC ensemble members but is much less
prominent amongst the GFS ensemble. A more northerly track would
limit chances of showers and thunderstorms to the northern
mountains, but still bring continued cool temperatures and
breezy winds. By late Tuesday and Wednesday, models project the
upper level trough to lose amplitude and temperatures to rise
closer to normal, with drier conditions and decreasing winds
also expected.

&&

.AVIATION...VFR and mostly clear. Surface winds: W-NW 5-15 kt,
with gusts 20-25 kt KBOI southeast through the Magic Valley
terminals. Winds becoming variable 10 kt or less tonight. Winds
aloft at 10kft MSL: W-SW 15-25 kt.

KBOI...VFR under clear skies. Surface winds: NW 7-13 kt with gusts
up to 20 kt this afternoon, decreasing this evening and becoming
variable 6 kt or less by 06Z/Thu.

&&

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

&&

$$VFR under clear skies. Surface winds: NW 7-13 kt with gusts
up to 20 kt this afternoon, decreasing this evening and becoming
variable 6 kt or less by 06Z/Thu.

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SHORT TERM...LC
LONG TERM....ST
AVIATION.....ST