497
FXUS65 KBOI 180956
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
356 AM MDT Thu Jul 18 2024

.SHORT TERM...Today through Saturday night...A weak shortwave
over northern ID will continue to move northeast today, and the
upper level ridge will reamplify. Amplification of the ridge
supports a couple of degrees of warming today. Some monsoonal
moisture over NV will move northward into the southwestern
Idaho highlands this afternoon, mainly over Owyhee County and
southern Twin Falls County. Storms will be capable of gusty
erratic outflow winds up to 50 mph. The ridge will continue to
strengthen and expand over southwest Idaho and southeast Oregon
through Sunday, with another prolonged heat wave. A weak
shortwave will move across eastern OR and southwest Idaho on
Friday morning, enhancing the threat of thunderstorms, mainly on
the Idaho side through late Friday afternoon. Thunderstorms
will be high-based with little rainfall and result in additional
fire weather concerns. Storms will also be capable of gusty
outflow winds. Smoke will persist across the area. Excessive
heat warnings remain in effect. Temperatures will warm to near
record levels, around 10-15 degrees above normal by Sunday.

.LONG TERM...Sunday through Thursday...Smoky conditions continue.
Upper level ridge will strengthen and reach peak amplitude over
southwest Idaho and southeast Oregon Sunday and Monday. This
will bring hotter temperatures to the area, with many lower
valley locations reaching 105 to 110 degrees through Tuesday.
Record highs will likely be broken in many areas during this
time period, however smoke may keep temperatures a few degrees
below forecast depending on how thick the smoke is. Limited
moisture will remain trapped within the upper level ridge,
resulting in a 10-20% chance of showers and thunderstorms across
the higher terrain on Sunday and Monday.

&&

.AVIATION...Smoky, local visibilities to MVFR/IFR. High density
altitude due to heat. Isolated to scattered thunderstorms
during the afternoon, mainly south of KTWF KJER. Surface winds
variable 5-10kt, becoming W-SW 5-15kt during the afternoon.
Gusty erratic outflow winds up to 45kt in vicinity of
thunderstorms near KTWF KJER. Winds aloft at 10kft MSL: SW
5-15kt.

KBOI...VFR. Smoky. High density altitude due to heat. Surface
winds SE 5-10kt, shifting to NW 5-10kt during the afternoon.

Weekend Outlook...Smoke reducing visibilities. Isolated
thunderstorms on Saturday afternoon mainly near NV border, then
isolated thunderstorms Sunday afternoon mainly over the higher
terrain.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning until 9 PM MDT this evening IDZ423-426.
     Excessive Heat Warning from noon today to noon MDT Saturday
     IDZ012-014-033.
     Excessive Heat Watch from Saturday afternoon through Tuesday
     evening IDZ012-014-016-030-033.
OR...Excessive Heat Warning from noon today to noon MDT Saturday
     ORZ064.
     Excessive Heat Watch from Saturday afternoon through Tuesday
     evening ORZ062>064.

&&

$$

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SHORT TERM...KA
LONG TERM....KA
AVIATION.....KA