876
FXUS65 KPIH 172036
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
236 PM MDT Fri May 17 2024

.SHORT TERM...Today and Saturday.
There is a strong trough moving through southeast Idaho currently
with weak high pressure ridging just off the Oregon and
Washington coasts. There is an upper level low just off the
southern British Columbia coast.

Winds are strong across the area currently, with widespread gusts
of 40 to 50 mph with isolated gusts near 60 mph. There is blowing
dust across the area, especially near the Blackfoot rest area
and, to a lesser, degree Arbon valley. Current wind advisories and
high wind warnings are in effect until early this evening.
Temperatures are near normal to slightly below normal across the
area, mid 60s to lower 70s for valley areas.

Saturday high pressure ridging develops over northern Idaho and
weak high pressure looks to build in slightly across southeast
Idaho. However, winds aloft look to remain mostly zonal. Expect
slightly breezy winds tomorrow afternoon with gusts near 20 mph
for most locations. The Arco desert will see gusts near 35 mph,
possibly around 40 mph. Will hold off on a wind advisory for the
Arco desert. Winds for the American Falls reservoir look to be
around 5 mph below the criteria for a lake wind advisory. Again,
have held off on a lake wind advisory for American Falls reservoir
for Saturday afternoon. Temperatures will be near normal for
tomorrow`s high temperatures, 60s and low 70s.
Wyatt

.LONG TERM...Sunday through next Friday.
The long term period begins with a shallow upper trough situated
over the northwest and shortwave passing through northern Idaho.
Enhanced 700mb westerly winds will lend to breezy surface
conditions, with sustained winds ranging 25 to 35 mph and gusts 35
to 45 mph. We will likely need a Wind Advisory for the Upper and
Lower Snake River Plain and Arco Desert/Mud Lake zones. Considering
the location of the shortwave, precipitation chances will likely be
limited to the northern extent of our CWA on Sunday, with National
Blend PoPs generally 35 percent and lower. Models show a closed low
forming over southern Idaho late Monday into early Tuesday as the
trough progresses eastward, which will support more widespread
precipitation chances. Late Tuesday into early Wednesday will be a
brief break behind the departing low and ahead of the next system. A
well-organized low will drop south into the Pacific Northwest on
Wednesday. The deterministic ECMWF continues to show the low passing
directly over Idaho on Thursday while the GFS shows the low tracking
south into Oregon before shifting eastward and over Idaho on Friday.
Chances for precipitation will become widespread again on Thursday,
however, 500 mb ensemble clusters still show differences
predominately in the depth of the low. Daytime highs will run 5 to
10 degrees below normal throughout much of the week. The National
Blend features the warmest temps of the entire extended period on
Friday, which favors the faster progression of the low and brief
zonal or weak ridging on Friday featured in the ECMWF.
Cropp

&&

.AVIATION...
Impacts today will continue to be the strong winds and resultant
reductions in VIS due to BLDU. The period of strongest winds today
will continue through around 23z before tapering off after that.
Expect sustained winds over 30 kts at KPIH and KIDA with gusts
generally 40 to 50 kts with relatively lighter winds at KBYI and
KDIJ, where sustained winds are forecast to reach up to 30 kts and
gusts up to 40 kts. KSUN will observe the lightest winds of all
terminals with typical diurnal wind patterns returning by late
tonight.
Cropp

&&

.HYDROLOGY...A flood warning continues for the Portneuf river in
Pocatello.  A flood advisory continues along the Portneuf river at
Topaz. Water levels are slowly receding for the Portneuf river due
to the snowpack diminishing. Water levels for other rivers,
including the Big Wood, Big Lost, Henrys Fork, Teton, and Snake, are
continuing to slowly climb due to snowmelt, but all rivers look
to remain below action stage with current forecasts.
Wyatt

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 8 PM MDT this evening for IDZ051-055>058-062-
065-067-068-070.

High Wind Warning until 8 PM MDT this evening for IDZ052>054.

&&

$$