788
FXUS65 KBOI 091549
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
949 AM MDT Sun Jun 9 2024

.DISCUSSION...Forecast remains on track for scattered
thunderstorms to develop early this afternoon. The morning 12 Z
sounding from KBOI showed 0.86 inches of precipitable water and
surface observations show dewpoint values in the mid to upper
50s across much of southwestern Idaho and southeastern Oregon.
In addition to the moisture, forecast afternoon soundings
depict the atmosphere becoming very unstable this afternoon with
surface based CAPE expected to reach 800 to 1000 J/kg by 00z.
This all supports a marginal risk of a few thunderstorms
producing severe wind gusts and hail. Some of these
thunderstorms will also produce brief heavy rain, but will be
moving northeast at about 30 mph, which will limit total
accumulations along their path. Morning WSR-88D radar and GOES
satellite imagery at 15:45 Z already show a band of scattered
showers extending from northern Harney County through Baker
County. So far...this band of showers is not producing much
lighting, but this will likely be the first area where
thunderstorms develop and then move north and east across the
area later this afternoon.

&&

.AVIATION...Mainly VFR. Isolated showers/thunderstorms will become
widespread across the E Oregon and SW Idaho this afternoon through
tonight, impacting all TAF sites. Storms may be capable of strong
winds 35-50 kt, hail, frequent lightning, and heavy rain producing
MVFR conditions. Surface winds outside of storms: variable or NW 5-
15 kt, except NW 15-35 kt this evening with cold front. Winds aloft
at 10kft: SE to SW 5-15 kt, then W-NW 10-20 kt this eve.

KBOI...Mainly VFR. A series of showers and thunderstorms expected
at, or in vicinity of, KBOI, with best chance Sun/22Z to Mon/04Z.
Thunderstorms capable of strong gusty winds 35-50 kt, hail, frequent
lightning, and heavy rain producing MVFR conditions. Surface winds
outside of storms: NW 5-15 kt, except 15-35 kt with cold front
passage at approximately Mon/00-03Z.

&&
&&

.PREV DISCUSSION...
SHORT TERM...Today through Tuesday night...A short wave trough
will move toward and then over the state today into this
evening. This will likely produce a greater coverage of
thunderstorms than we have seen the past few days. SPC has
placed roughly the southern half of the CWA in a marginal risk
for severe weather, with winds being the main threat. Storms
were ongoing mainly over the mountains of SW Idaho with isolated
storms in SE OR as of 0745Z. New development is expected around
18Z today, with storms moving northeast around 25 mph. Storms
should exit the area around midnight Sunday night. Weak ridging
aloft will move in Monday behind the departing trough, followed
by zonal flow Tue and Tue night. These features will keep us dry
and warm (roughly 10 degrees above normal) both days.

LONG TERM...Wednesday through Sunday...Zonal flow Wed will
become SW Thursday and Friday, keeping us warm and dry. Models
are consistent in depicting an upper level trough moving into
the PacNW Friday night through Sunday, but differ in important
ways on the details. At this time, the most likely solution is
one with the low staying to our north, keeping us dry. We should
be warm Friday, with temperatures cooling to near normal Sat
and perhaps below normal Sunday.

&&

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

&&

$$

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DISCUSSION...JB
AVIATION.....SH
SHORT TERM...SP
LONG TERM....SP