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000
FXUS65 KPIH 130852
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
252 AM MDT Sat Apr 13 2024

.SHORT TERM...Today and Sunday
Expecting a relatively quiet Saturday across eastern Idaho as weak
high pressure regains control across the region. Off the northern
California coast, a potent upper low will move over CA later today
and move through the Great Basin during the day Sunday. This will
keep the region under strong southerly flow over the next few days
keeping temperatures on the warmer side of normal. Temps today will
again top out in the upper 60s to mid 70s in the lower valleys which
is around 10-15 degrees above normal for this time of year.
Southerly winds will be in the 10-15 mph range for much of the day.
Not expecting much in the way of precip, if any. Hi-res CAMs show
a very isolated chance across the far northernmost portions of
our forecast area but the better chances appear to be in central
Idaho and western Montana. Nevertheless, a very isolated shower
can`t be ruled out but much of the region should be dry with
mostly clear skies.

As the aforementioned low moves into the Great Basin on Sunday,
the pressure gradient will tighten and winds will accordingly
increase somewhat regionwide. Strongest winds will be along the
Nevada and Utah borders where winds in the 20-25 mph range, with
higher gusts, seem probable with 15-20 likely for much of the rest
of eastern Idaho. This will be below any headline levels but we
could flirt with an advisory in the South Hills if things trend
upwards just a bit more. With H5 height falls on Sunday, daytime
highs won`t be nearly as high as Friday and Saturday and will
likely be 5-8 degrees below our Saturday maximums. This would
still be above normal for this time of year but noticeably cooler
nevertheless. With the low being closer, could squeeze out a few
high elevation showers in the south/southeast highlands late
Sunday and maybe into the central mountains as well. Again though,
most locations should be dry. McKaughan

.LONG TERM...Mon through Fri night
There has been a tremendous shift in expectations for this period
from 24 hours ago. Previously, after the Great Basin low passed
to the east, a low from the north slide directly over the Gem
State and lingers over southern Idaho for a couple of days, which
would be typical behavior of a closed low. But 24 hours later,
this closed low stays farther north. This means no cold air
surging across the Great Divide. A stronger zonal flow aloft makes
for windier conditions now on different days. Only about a
quarter of the cluster members even have the close low south
enough to be truly impactful. Precipitation amounts were never
much, but temperatures once expected to cool to highs in the upper
40s by mid-week now are expected to stay at 60 deg F or higher.
So, less snow with warmer temperatures.

Windy days appear to be Mon afternoon through Wed afternoon,
including overnights. Then breezy each afternoon for Thu and Fri.

Really don`t know if this major flip-flop is trustworthy. There were
a few signs with a minority of solutions yesterday, but this is a
tremendous change from the previous consensus. Messick


&&

.AVIATION...
VFR conditions expected through the period with no precipitation
expected and mostly clear skies. The only concern will be for
southerly winds to become breezy and occasionally gusty later
this afternoon at KPIH, KIDA and KBYI. Gusts will likely be in the
20-25 kt range so nothing overly unusual for eastern Idaho but
can still cause some aviation concerns. McKaughan

&&

.HYDROLOGY...
Water levels remain elevated on the Portneuf River in Pocatello and
Topaz where River Flood Warnings and an advisory, respectively,
remain in place. With warm temps continuing for a few more days,
expecting continued mid/high elevation snowmelt which should lead to
rises at both gauges over the days ahead. The Portneuf at
Pocatello is forecast to come close to moderate flood stage during
the early part of the work week. Stay tuned for further updates
over the days ahead. McKaughan

&&

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

$$