696
FXUS65 KPIH 091910
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
110 PM MDT Sun Jun 9 2024

.SHORT TERM...Tonight through Monday Night.
Early afternoon satellite imagery shows a H5 trough moving
onshore to the PacNW and NRN Rockies which is going to drive a
cold front across SRN Idaho later today into early Monday.
Scattered showers and isolated thunderstorms are already ongoing
and are expected to increase in areal coverage and intensity with
between 1-5 PM being the main time that stronger storms will get
going. The convective environment today remains conducive for the
potential of stronger thunderstorms with 800-1400 J/kg of SBCAPE,
20-30 kts of 0-6 km shear, and 7-9 degree/km 700-500 mb lapse
rates. This environment will support strong outflow winds in
excess of 40-50 mph, small hail, and heavy downpours with more
organized convection. The primary threat among these three will
center around winds with strong outflows and potential
microbursts supported by around 600-1000 J/kg of DCAPE. Storm
motion will generally be SW to NE through this evening with
activity turning more isolated after midnight tonight as lingering
showers and storms continue across ERN Idaho.

As this H5 trough moves east through Montana on Monday, much
drier air will begin to move into our region behind a cold frontal
boundary which will bring much drier conditions across SE Idaho.
Any activity Monday will remain isolated in nature and generally
confined east of I-15 into Wyoming with dry conditions returning
regionwide for Monday night into Tuesday associated with that
drier air now in place. This drier air mass will also work to cool
temperatures slightly with highs Sunday in the upper 70s to upper
80s, cooling by about 4-8 degrees for Monday with highs dropping
to the low 70s to low 80s. While synoptic winds have stayed
generally light over the past several days, increasing 700 mb
winds aloft generally around 20-30 kts will support winds up to
15-25 mph across the Snake River Plain and Magic Valley. MacKay

.LONG TERM...Tuesday through next Sunday.
Late Monday into Tuesday models continue to show weak high
pressure building in across the area bringing dry conditions,
slightly breezy winds (gusts of 20 to 30 mph), and warmer
temperatures Tuesday. Models continue to show a weak trough moving
well north of Southeast Idaho on Wednesday causing zonal flow
aloft with breezy winds (gusts of 25 to 40 mph) at the surface
with the strongest winds over the Arco desert. Late Wednesday into
Thursday models still show weak high pressure building back in
before bringing a trough/cold front through the area on Friday
into Saturday. Expect dry conditions Tuesday through Thursday.
Will see an increase in the chance for convection with showers and
thunderstorms Friday, mainly along the Montana Divide. Saturday
looks mostly dry, but breezy, with showers and thunderstorms
mainly across the Island Park area. Look for temperatures 8 to 12
degrees above normal by mid week before becoming 10 to 15 degrees
above normal by the end of the week. Thursday will likely be the
warmest day of the week, with temperatures possibly hitting 90
degrees (40 to 70 percent chance from NBM model) for some lower
areas across the Shoshone, Eastern Magic Valley, Southern Snake
Plain, Raft river, and the Franklin/Oneida/Cache Valley regions.
Temperatures look to drop quite a bit on Saturday, becoming near
normal (50/60s in mountains and mid to upper 70s for lower
valleys) before dropping 3 to 6 degrees below normal on Sunday.
Wyatt

&&

.AVIATION...For the 18Z TAFS through 18Z Monday.
A cold front will move through this afternoon, which will bring
scattered to numerous showers and thunderstorms for all TAF sites
starting around 3 pm and ending around 8 to 9 pm. Thunderstorm
outflows will be in general in excess of 40 to 50 mph. The HREF
models shows a 70 to 80 percent chance for thunderstorms on
station for KSUN and a 80 to 90 percent chance for thunderstorms
on station for the rest of our TAF sites. Expect vicinity showers
overnight before gradually clearing out tomorrow morning as winds
become slightly breezy. Wyatt

&&

.FIRE WEATHER...
We will see an increase in shower/thunderstorm coverage and
potential for rainfall during the day. Lightning probabilities
reach 30-60% across all of central and eastern Idaho except right
around Bear Lake. Chance of wetting rains will be highest across
the central mountains where they peak at 45-75% this afternoon and
evening. Another "peak" will be across the South Hills/Albion
Mountains and south end of the Magic Valley (Zones 425 and 427),
where they hit 45-65%. Elsewhere, look for an average of 20-40%.
Lingering showers and storms are expected Monday across portions
of Zones 410, 411, 413 and 476. Rainfall potential drops off quite
a bit, with only 20-40% around Island Park on the high end.
Tuesday-Thursday still looks dry, warm and breezy across all
areas. Keyes

&&

.HYDROLOGY...
A FLOOD WARNING remains in effect for the Teton River near Driggs
as small streams/creeks and the main stem river continue to run
high. Minor flooding is being observed on the main stem river and
is expected to remain at that level through midweek, aided by
additional snowmelt from the Tetons and Big Holes. Further
downstream along the Teton River near St. Anthony, that gage has
reached action stage and is expected to remain elevated through
midweek as well. Several other rivers across the CNTRL Mountains
are also seeing diurnal increases with the Big Lost River at
Howell Ranch currently hovering around action stage. Along the
Snake River, increased flows out of Palisades Reservoir has also
led to the Snake River near Heise gage climbing up to action stage
and it is expected to stay there for at least the next week.
MacKay

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$