806
FXUS65 KPIH 082050
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
250 PM MDT Sat Jun 8 2024

.SHORT TERM...Tonight through Sunday Night.
Early afternoon satellite imagery shows a broad H5 ridge of high
pressure over the WRN CONUS as a H5 shortwave troughs departs east
into Wyoming and Colorado. Lingering moisture behind this exiting
trough will work to support a 10-20% chance of thunderstorms this
afternoon and evening ahead of drier conditions returning
tonight. The HREF ensemble model supports this solution well with
best chances for convection today south and east of the Snake
River Plain with more isolated potential elsewhere. Radar imagery
this afternoon is showing the strongest thunderstorms in this area
which will need to be monitored. High temperatures today will
range from the upper 70s to low 90s which is about 10-20 degrees
above normal for this time of year. Pocatello and Challis also saw
their first 90 degree of the day yesterday, Friday June 7th, with
Burley and Idaho Falls both reaching 89 degrees this past week.

While conditions will remain quiet overnight, a warm front
lifting north out of the Great Basin will support increasing cloud
cover and morning showers ahead of a cold frontal passage Sunday
afternoon into Sunday night. These fronts are associated with a
H5 trough moving onshore to the PacNW and NRN Rockies throughout
the day Sunday which will support scattered to numerous
thunderstorm development. The HREF ensemble model shows a 60-90%
chance of thunderstorms across our region with an emphasis on
strong outflows and microburst potential. This convective
environment is supported by 500-1000 J/kg of SBCAPE, 500-800 J/kg
of DCAPE, 25-35 kt 0-6 km shear, and 8-9 degree/km 700-500 mb
lapse rates. Any stronger storms that are able to sustain
themselves in this environment will be capable of producing wind
gusts in excess of 40-50 mph with potential microbursts producing
winds in excess of 60-70 mph. As a result, SPC has outlined much
of our region in a MARGINAL RISK (1/5 risk level) for severe
weather tomorrow. Highs tomorrow will remain consistent with
Saturday reaching the upper 70s to low 90s ahead of cooler
temperatures moving in for Monday behind Sunday`s cold front.
MacKay

.LONG TERM...Monday through next Saturday.
Look for lingering scattered showers and thunderstorms mainly
across our northeast areas by Island Park in the morning and
afternoon from an exiting system that hits the area Sunday. Late
Monday into Tuesday models 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. Late Wednesday into
Thursday models still show weak high pressure building back in
before bringing a weak trough through the area on Friday. Expect
dry conditions Tuesday through Thursday. Will see an increase in
the chance for convection with showers and thunderstorms Friday,
mainly in the Eastern Highlands along the Wyoming border. Monday,
temperatures will be the coolest for the week, a few degrees above
normal. 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 likely hitting 90 degrees (60 to 80 percent
chance from NBM model) for some lower areas across the Shoshone,
Eastern Magic Valley, Southern Snake Plain, Raft river, and the
Franklin/Oneida regions. Wyatt

&&

.AVIATION...For the 18Z TAFS through 18Z Sunday.
Lingering moisture will allow for vicinity showers with heating
this afternoon for all TAF sites. KBYI has the best chance for
vicinity thunderstorms, but even then the thunderstorms looks to
stay just south of KBYI in the mountains. Winds will remain
overall light this afternoon though slightly breezy southwesterly
winds up to around 15 mph are likely for KPIH, KIDA, and, to a
lesser degree, KBYI. KBYI could see thunderstorm outflows of
around 20 to 30 mph this afternoon into early evening.

Tomorrow morning expect scattered showers moving in from the west
and moving east by late late morning associated with a warm
front. By the afternoon Sunday a cold front moves through the
area, which will bring scattered showers and thunderstorms for all
TAF sites. Thunderstorm outflows will be around 40 to 50 mph.
Wyatt

&&

.FIRE WEATHER...
We will another round of showers and storms today, although
coverage will be limited. Raw thunder probabilities are running up
to 20%, possibly as high as 30% across Zone 427. We nudged down
to keep them at 20% or less in the forecast. The risk of
thunderstorms actually will extend until around midnight...with
lingering showers after midnight.Chance of wetting rains will run
well under 10% through tonight. Wind gusts over 35 mph are the
main issue with storms today. Sunday will be the wettest day of
the weekend, along with the highest potential for thunderstorms
across the area. Our Blend of Models lightning probabilities are
running 30-50% everywhere EXCEPT across the Magic Valley and
across 413 near Bear Lake. Other high- resolution probabilities
are running 20% higher, but may be overdone...especially with the
potential for morning rain and thunderstorms. We did push the
final potential above 30% except around the Bear Lake area. Gusty
winds are once again likely. Chance of wetting rains will be under
20% across the southeast corner of 413 and also north of Idaho
Falls in 410. Elsewhere, percentages increase with the highest
probabilities across the central mountains and the higher
elevations of Zone 427. Showers and storms gradually clear
northwest to southeast tomorrow night and Monday. Most of next
week should end up dry and warmer. It does look breezy though as a
strong westerly flow sets up across the state and region. 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 much of next week,
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 forecast to reach that
tonight and remain elevated into next week.

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.

&&

$$