524
FXUS65 KPIH 172042
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
242 PM MDT Wed Jul 17 2024

.SHORT TERM...Today through Thursday Night.
Scattered thunderstorms are ongoing through parts of the South Hills
already this afternoon. These storms are expected to remain dry as
even the 90th percentile QPF through the evening is less than 0.10
inches. Storms will be capable of producing 45 to 50 mph gusts, but
given the classic inverted V soundings, DCAPE near 1500 J/kg in the
South Hills, and steep lapse rates, a few stronger gusts aren`t out
of the question as storms collapse and outflows start running
around. Activity should be diminished by midnight. These scattered
dry storms are the driver for the Red Flag Warning currently out and
expected redevelopment Thursday afternoon is responsible for the
extension through Thursday evening. Aside from the storms, it`s hot
out there with highs today in the upper 80s to low and mid 90s
through the valley locations. Highs on Thursday will be almost a
repeat, though some areas will see highs increase another degree or
two. By Thursday afternoon, storms will develop once again with
scattered activity in the South Hills once again with more isolated
activity throughout all of Eastern Idaho. Expect similar storms with
lightning and wind gusts around 50 mph being the biggest threats.
Outside of convection, our synoptic wind gusts today and tomorrow
will range from 20 to 25 mph.
AMM

.LONG TERM...Friday through Wednesday. Ensembles maintain strong
persistence and consistency with ongoing high pressure pattern.
Ridge axis remains over the Great Basin, and amplifies well north
into Canada over the weekend. This should limit deep monsoonal flow,
but deep Pacific flow with large low in the Gulf of Alaska could
still shuttle some moisture into the region. Thus still can`t rule
out isolated thunderstorms day by day. Upper low shifts inland into
Canada Tuesday/Wednesday, helping to break down the ridge slightly.
DMH


&&

.AVIATION...Combination of convection and smoke impacts remain the
main concerns for terminal forecasts into Thursday afternoon. Smoke
plume projections take main push of smoke northeast tonight, but
could see occasional minor VFR reductions down to 6SM for a few
terminals, so kept that forecast in place through tonight.
Thunderstorms this afternoon and evening look to impact
KSUN/KBYI/KDIJ, with potential outflows 35-40kts and little
rainfall. Better chances exist into Thursday afternoon, and there is
some hint at early build-ups/weak shower potential for KDIJ by mid
morning tomorrow. Outside of the thunderstorm/smoke influence,
expect VFR conditions with sustained winds around/less than 10kts
and gusts around 20kts, mainly during max heating.
DMH


&&

.FIRE WEATHER...A Red Flag Warning continues for FWZ 427 in the South
Hills until 9 PM Thursday evening for scattered dry thunderstorms.
These isolated to scattered dry thunderstorms will continue to be
the name of the game through the rest of today and at least
through Thursday and Friday. The bulk of the scattered activity
this afternoon/evening is currently ongoing in the South Hills,
but isolated dry storm activity (10 to 20 percent chance) is
expected through portions of the Central Mountains and into the
higher elevations of the upper Snake River Plain and Eastern
Highlands. Storms will be capable of producing wind gusts around
45 to 50 mph, though some stronger gusts aren`t totally out of the
question. It is important to note that red flag conditions won`t
exist during the overnight hours once storms taper off, but
decided to extend the warning for 427 since more scattered dry
storms are expected Thursday afternoon and evening. Coverage
continues to teeter on the edge of isolated/scattered through
portions of zone 413 on Thursday and isolated dry storms are
expected throughout much of eastern Idaho as a whole. Once again,
the lightning and strong wind gusts near 50 mph will be the main
threats. As the model trend has been to increase storm coverage
with each run, the potential exists that 413 may need to be added
to the RFW for Thursday storms. Outside of storms, synoptic wind
gusts will range from 20 to 25 mph. Minimum relative humidity on
Thursday will be lowest through parts of zones 422, 425, 475, and
476 ranging from about 10 to 20 percent. Elsewhere, min RHs will
be 18 to 28 percent.
AMM


&&

.AIR QUALITY...Ridge of high pressure still in place allowing for
moisture to rotate around the high through East Idaho for several
more days. Increased wildfire activity across the western states,
including in Idaho, will continue to provide periods of smoke/haze.
Continued activity on the Bench Lake Fire will keep smoke entrenched
throughout the Sawtooth Valley, possibly progressing along the
Salmon River toward Salmon and into adjacent valleys, especially
during overnight inversions. Additional smoke concerns will be
highly dependent on whether thunderstorm activity today starts any
new fire activity.
DMH


&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 PM MDT Thursday for IDZ427.

&&

$$