361
FXUS65 KPIH 112038
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
238 PM MDT Tue Jun 11 2024

.SHORT TERM...Today and Wednesday.
High pressure ridging is in place over the area with the high
pressure ridge just east of Southeast Idaho. There is an
approaching trough and resulting zonal flow aloft just northwest
of our area over northwest Washington. Today will be mostly clear
and breezy, with gusts near 20 to 35 mph this afternoon. Tomorrow
the trough passes north of our area. No precipitation is expected
Wednesday with this trough but winds will get breezy in the
afternoon with gusts of 25 to 45 mph. The Arco desert will see
the strongest winds. Winds on the American Falls reservoir look to
be just below lake wind criteria (20 mph sustained) tomorrow
afternoon. The HREF model shows a 0% percent chance of reaching 20
mph on the reservoir. However, the NBM model shows a 20% chance
of reaching 20 mph on the southwest end of the lake and a 60%
chance of reaching 20 mph on the northeast end of the lake. In
either event, the lake will be choppy, especially from around 3 pm
to 8 pm. Temperatures will be about 8 to 12 degrees above normal
today and tomorrow.
Wyatt

.LONG TERM...Thursday through next Tuesday.
Our weather will still be warm on Thursday, but as a low off the
coast of southern California moves into the southwest, that will
begin to change. Thursday will be warm and dry with highs in the 80s
to low 90s through the Snake Plain and eastern Magic Valley, but
with a the aforementioned low to our south and another low to our
north moving into southern British Columbia, will will be
sandwiched between precipitation, but not receiving much for
ourselves. In fact, the bulk of the precip will stay to our north
and south, but we introduce PoPs of about 20 to 40 percent on Friday
afternoon, mostly in the Eastern Highlands. With the increased cloud
cover on Friday, our highs will be about 5 degrees cooler. Once a
cold front passes through our area late Friday into Saturday,
temperatures will drop in a more significant way. Highs for Saturday
will be in the low to mid 70s for all with only a few low 80s
lingering farther south near the Malad City, Holbrook, and Franklin
areas, but by Sunday we`ll be another 5 degrees cooler keeping
everyone in the low to mid 70s. Another low drops southward out of
the Pacific NW early next week and will bring a re-enforcing round
of cooler air with it along with better rain chances. This will drop
highs into the mid and upper 60s on Monday and bring PoPs of about
20 to 40 percent again to parts of the Central Mountains, upper
Snake Plain, and Eastern Highlands. Depending on how quickly this
system moves out (and depending on which model you`d like to believe
as the GFS is slower to move it out than the ECMWF), we will keep
around some precip chances for Tuesday as temperatures warm into the
low to mid 70s. It will be breezy to windy nearly every afternoon of
the extended forecast with gusts of 25 to 35 mph through the eastern
Magic Valley and Snake Plain each afternoon with Saturday looking
like the windiest day.
AMM

&&

.AVIATION...18Z Tuesday through 18Z Wednesday.
High pressure under strong westerly zonal flow aloft across the area
will keep our weather quiet today and tomorrow. The main aviation
impacts will be wind gusts each afternoon. Gusts this afternoon will
range from 15 to 20 kts at SUN, BYI, DIJ, and PIH with stronger
gusts near 25 to 30 kts at IDA. They will drop off overnight, but
pick up once again for Wednesday afternoon with gusts of 20 to 25
kts at SUN, BYI, PIH, and DIJ while pushing closer to 35 kts at IDA.
AMM

&&

.FIRE WEATHER...Warm up and drying out continues through Thu
afternoon. Lower elevation humidity in the central Idaho mountains
and eastern Magic Valley should drop below 15 percent on at least
two of the three days. Expect afternoon/evening gusty wind each day,
with an increase in the wind on Fri.

Humidity will start to rise with the approach of a front on Fri,
then what looks like a fairly dry cold front will push through on
Sat, amping up the wind and producing dry thunderstorms.
Messick

&&

.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 Teton River near
Driggs and is expected to remain at that level through Saturday,
aided by additional snowmelt from the Tetons and Big Holes. The
latest NWRFC forecast shows this gage peaking Wednesday and
dropping below minor stage on Saturday. The warmest temperatures
this week are expected this Thursday, which will keep flows going
through early Saturday. However, below normal temperatures this
weekend, along with a diminishing snowpack, will cause flows to
drop off fairly quickly this weekend into early next week. Further
downstream along the Teton River near St. Anthony. This gage
remains at action stage and crested yesterday and is forecasted to
come down below action stage by Friday.

Several other rivers across Southeast Idaho are also seeing
diurnal increases. The Big Lost River at Howell Ranch is still
currently hovering just below action stage. The Mackay Reservoir
will fill in the next day or two, which will cause increased flows
below the Mackay Reservoir on the Big Lost River. Along the Snake
River, increased flows out of Palisades Reservoir have led to the
Snake River near Heise to climb up to action stage and it is
expected to stay there until further notice.
MacKay/Wyatt

&&

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

$$