219
FXUS65 KBOI 111953
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
153 PM MDT Thu Jul 11 2024

.SHORT TERM...Tonight through Saturday night...The excessive
heat continues through Saturday as a strong upper ridge remains
positioned between the Great Basin and Colorado Rockies. Lower
elevations continue to see high temperatures of 102-106. An
increasing number of wildfires has increased smoke cover, and
some uncertainty remains about how much this will reduce
afternoon highs. As the ridge moves closer to Colorado, the
backside southerly flow will bring a moisture push beginning
late Friday through Saturday night. Each afternoon/evening
high-based showers/thunderstorms are possible in areas along the
NV border. There is low confidence in how quickly the moisture
reaches us, thus a later push would reduce precip potential on
Friday. Greater confidence on Saturday, with PWs reaching about
0.7 inches. Hot and dry surface environments show up in forecast
soundings as what appears to be an inverted V signature. This
has us most concerned about outflow winds, even if precipitation
doesn`t reach the ground. A fire weather watch has been issued
for Saturday through the short term to highlight the lightning
threat on top of very dry fuels.

.LONG TERM...Sunday through Thursday...Sunday has the highest
probability for thunderstorms (30% chance) as the deepest moisture
arrives in advance of a shortwave trough. The combination of heat,
moisture and lift from the approaching trough will fuel more
widespread afternoon/evening thunderstorm development than we see on
Saturday. The near surface environment will favor strong outflow
winds from showers and storms similar to Saturday. The trough moves
into central Idaho on Monday with about a 15% chance of showers and
thunderstorms across portions of the west central Idaho mountain.
The upper level ridge remains over southern Nevada/Utah/Northern
Arizona through Tuesday through Thursday. This will keep the threat
for afternoon thunderstorms going across south-central Idaho.
Temperatures will remain quite warm through the period although
increased for potentially numerous fires could limit max
temperatures a bit.

&&

.AVIATION...VFR, General reduction in visibility due to smoke.
High density altitude due to very hot daytime temperatures.
Surface winds: NW winds 5-15kts, becoming light and variable
overnight. Winds aloft at 10kft MSL: W-SW 10-20 kt.

KBOI...VFR, smoke layers aloft. High density altitude due to
very hot daytime temperatures. NW winds through the day with
some infrequent afternoon gusts, becoming light and variable S
to E overnight.

Weekend Outlook...VFR, with smoke reducing visibility. There is
an increasing chance of high-based afternoon showers and
thunderstorms with greater coverage expected Sunday. Development
will focus over higher terrain above the Snake River Plain. Gusty
outflow winds will be possible from showers/storms that
develop.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Fire Weather Watch from Sunday afternoon through Sunday
     evening IDZ400>402-420-424.
     Excessive Heat Warning until midnight MDT Sunday night IDZ012.
     Fire Weather Watch from Saturday afternoon through Sunday
     evening IDZ423-426.
     Excessive Heat Warning until midnight MDT Saturday night
     IDZ014-033.
     Heat Advisory until midnight MDT Saturday night
     IDZ015-016-029-030.
     Heat Advisory from midnight Saturday night to midnight MDT
     Sunday night IDZ033.
OR...Excessive Heat Warning until midnight MDT Sunday night ORZ064.
     Fire Weather Watch from Saturday afternoon through Sunday
     evening ORZ636-637-646.
     Excessive Heat Warning until midnight MDT /11 PM PDT/ Saturday
     night ORZ062-063.
     Heat Advisory until 11 PM PDT Saturday ORZ061.
     Heat Advisory from midnight MDT /11 PM PDT/ Saturday night to
     midnight MDT /11 PM PDT/ Sunday night ORZ062-063.

&&

$$

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SHORT TERM...JM
LONG TERM....JDS
AVIATION.....JM