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637
FXUS65 KPIH 260930
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
330 AM MDT Wed Jun 26 2024

.SHORT TERM...
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Today through Thursday Night.
Early morning radar imagery shows a warm front lifting NE out of
the NRN Great Basin with scattered showers and an embedded
thunderstorm or two. As this main precipitation and cloud shield
lift NE courtesy of SW flow, mostly cloudy skies in the morning
will give way to partly to mostly sunny skies later this morning
into the afternoon hours, aiding in generating around 400-800
J/kg of SBCAPE. This instability coupled with 25-35 kts of 0-6 km
shear, 0-75-1.00" PWATS, and 7-8 degree/km 700-500 mb lapse rates
will support scattered thunderstorms this afternoon and evening
with the HREF model probability of thunder showing a 50-80% chance
across our entire CWA. Stronger storms will be capable of
producing wind gusts in excess of 40-50 mph, small hail, and heavy
rain with the timeframe for these storms generally in that 2-10
PM MDT range.

Drier air will then fill in behind this exiting warm front into
Montana tonight with a return to predominantly dry conditions
outside of isolated showers and thunderstorms across ERN Idaho as
a H5 low in the NE Pacific moves onshore to the PacNW and WRN
Canada. This system will drive a cold front across SRN Idaho on
Thursday with best chances for convection shifting to along the
Montana, Utah, and Wyoming border regions as strong winds usher in
a drier and cooler air mass from the west. Strong daytime mixing
and 30-45 kt 700 mb winds will support peak winds on Thursday in
that 25-45 mph range with gusts up to 40-65 mph. As a result, WIND
ADVISORIES will likely be needed with the potential for HIGH WIND
WARNINGS across the Upper Snake River Plain and Arco/Mud Lake
Desert up into Clark County region where a 30-60% chance of wind
gusts greater than 60 mph exists. Have gone ahead with a HIGH WIND
WATCH for this area with WIND ADVISORIES likely needed for
surrounding zones around this watch. Winds will subside Thursday
evening with a cooler, drier, and more stable airmass moving into
place for Friday. MacKay

.LONG TERM...Friday through next Wednesday.
Dry and seasonably cool temperatures are expected for Friday
behind Thursday`s cold front with lows in the 30s/40s/50s and
highs in the 60s/70s to low 80s. Winds will also be much quieter,
staying less than 20 mph as skies remain mostly clear. A H5 ridge
of high pressure will then build in for Saturday, leading to high
temperatures about 8-12 degrees warmer in the 80s to low 90s as
light winds persist. An approaching Pacific trough in the NE
Pacific will move onshore for Sunday which will help to introduce
some isolated shower and thunderstorm chances into Monday in
addition to an uptick in winds. Sustained winds both Sunday and
Monday will peak each afternoon around 20-35 mph with gusts to
30-50 mph. Temperatures on Monday will be about 6-10 degrees
colder than the weekend behind a cold front with highs back in the
70s to low 80s. Dry, zonal flow will keep temperatures seasonable
through Tuesday ahead of warming conditions heading into
Independence Day courtesy of SW flow building back in midweek as
conditions remain dry and breezy. MacKay
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.AVIATION...
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For the 12Z TAFS through 12Z Thursday.
Predominant VFR conditions are expected for Wednesday as a warm
front lifts NE out of the Great Basin. A mix of isolated to
scattered showers and thunderstorms are expected throughout the
day with an emphasis on stronger storm potential during the
afternoon and evening hours. The HREF model shows a 50-80% chance
of thunder at all terminals today with stronger storms capable of
producing wind gusts in excess of 30-40 kts, heavy rain, and
small hail. We may see some brief drops to MVFR/IFR conditions
should these storms move on station. Drier conditions will then
return overnight outside of isolated showers and storms across ERN
Idaho. A cold front in then expected to track across SRN Idaho on
Thursday, bringing with it strong winds out of the SW. MacKay
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.FIRE WEATHER...
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A Pacific trough moving onshore tonight into Thursday will
support isolated to scattered showers and thunderstorms today
regionwide as a warm front lifts NE out of the Great Basin. A cold
front is then expected to track across SRN Idaho for Thursday
with strong winds and drier conditions. Best chances for
convection Thursday will shift east throughout the day as
progressively drier and cooler conditions build in from the west.
The strongest winds Thursday around 30-45 mph with gusts up to 65
mph will be possible in FWZ 410, NE 425, and SRN 476. In addition
to strong winds, very dry conditions are also expected in this
area with afternoon humidities in the teens. Cooler temperatures
are then expected for both Thursday and Friday associated with
that cold front ahead of a weekend warmup as conditions remain dry
with much lighter winds on Friday and Saturday. A secondary
Pacific trough will then move onshore Sunday into Monday with
another round of isolated to scattered showers and thunderstorms
in addition to strong winds. Cooler weather will then return to
kickoff next week as temperatures gradually warm through
Independence Day with dry and breezy conditions persisting. MacKay
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.PIH WATCHES/WARNINGS/ADVISORIES...
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High Wind Watch from Thursday morning through Thursday evening
for IDZ052-053-067.
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