857
FXUS65 KPIH 291006
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
406 AM MDT Mon Apr 29 2024

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...
A shortwave trough will swing across the region today, bringing
scattered showers and t-storms this afternoon and evening. While
some shear will be available, instability will remain quite marginal
at generally less than 500 J/kg MUCAPE and soundings lack much
thickness to the CAPE distribution along with little to no veering
of the wind profile, all suggesting a garden-variety t-storm day
with brief heavy downpours, some lightning, brief gusty winds, and
perhaps small hail out of the strongest cells. The larger impact
will be increased west winds this afternoon and evening regionwide
as the pressure gradient tightens, with the ern Magic Valley/Snake
Plain corridor along with the adjacent Wood River Valley and Raft
River region reaching WIND ADVISORY criteria, which remains in place
unchanged. After highs in the 50s to low 60s today, skies will clear
and conditions will cool going into Tue with highs in the mid-40s to
mid-50s. At least isolated rain/snow shower activity is still
possible from the Central Mntns east across the Upper Snake
Highlands and along the WY border corridor, however, as low pressure
resides just to our north, while much of the Snake Plain southward
remains dry. Low temps Tue AM will likely drop below freezing across
the entire forecast area. 01

.LONG TERM...WEDNESDAY THROUGH NEXT MONDAY...
Active progressive weather pattern continues in the extended
period. It does seem certain that at least the first two mornings
of May will be cold, likely leading a season-opening Frost and/or
Freeze headline for the Snake Plain growing zones. Upper trough
passage Wednesday will continue to produce showers, and given the
cold temperatures, expect a mix of rain/snow to valley floors.
Unsettled conditions continue Thursday, with similar conditions
expected. QPF remains light throughout, so significant snow
accumulations are not expected even at higher elevations. Heading
into the weekend, we begin to lose the consensus in the clusters.
Some version of shallow trough remaining over the
northern/intermountain states Friday, and a weak ridge trying to
build into the coast. By Saturday, a deeper trough approaches the
coast, but the depth varies significantly between the GFS and
ECMWF and ensembles, with varying downstream impacts over Idaho.
Both deterministic GFS and ECMWF would remain dry over East Idaho
through the weekend, but the varying ensembles lead the NBM into
remaining weakly unsettled. DMH

&&

.AVIATION...
Fast moving shortwave trough impacts East Idaho today with a mix of
wind and showers/tstorms. Winds begin increasing after sunrise,
reaching sustained speeds of 25-30kts for KBYI/KPIH/KIDA and KDIJ.
KSUN wont completely escape, with winds sustained around 20kts this
afternoon. SHRA could begin filling in across higher elevation
areas, mainly impacting KSUN and KDIJ by late morning, and all sites
could see at least VCSH/VCTS after 21Z. Both winds and precip
diminish after sunset, though winds will likely remain breezy
at/around 15kts sustained for the Snake Plain terminals. DMH

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from noon today to midnight MDT tonight for
IDZ051>057-067-068-075.

&&

$$