Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 150857

Area Forecast Discussion
National Weather Service Pocatello ID
257 AM MDT Sun Oct 15 2017

.SHORT TERM...Today through Tue night. High pressure will continue
to build in from the south, keeping skies absolutley clear. The
upper level wind will shift from northwest to west and west-
southwest, allowing stronger warming from today to Mon 8 to 12 deg
F. Expect continued warming-another 4 to 8 deg F for Tue afternoon
and the Tue night low. Under the ridge, despite a strong westerly
gradient at 500mb, there appears to be little mixing to bring the
stronger wind down to the surface. The only fly in the ointment is
this morning as GOES imagery indicates possible stratus and fog in
the Snake River plain, Teton Valley and Upper Snake highlands.

.LONG TERM...Wee through Sun night. A weak impulse on Wed/Wed
night will help break down the ridge to the north of the forecast
area, but will bring little cloud this far south. In fact,
temperatures continue to rise as the wind shifts more southwest.
But this may be the last hurrah for Indian Summer as clouds move
in on Thu, bringing back a cooling trend and then rain and extreme
high elevation snow on Thu night. Temperatures will be down 10 to
14 deg F on Fri compared to Thu (although still above normal) with
some potentially moderate to heavy precipitation with the low.
After this low clears, the forecast confidence drops dramatically,
so a chance of precipitation continues, but timing and placement
differences make it difficult to pin down. Painted with a very
broad brush, and wanted to go drier on some days, but surrounding
offices have been hesitant to change much, so just nudged it
downward. Messick


.AVIATION...Dry NW flow aloft with VFR conditions expected
throughout the next 24hrs. Huston


.FIRE WEATHER...A dry and stable NW flow aloft was positioned over
the region early this morning and will continue throughout the day.
A ridge of high pressure will gradually build northward across the
Great Basin tonight and Monday resulting in dry and warmer
conditions Monday afternoon. The ridge will flatten some Tuesday as
a disturbance passes east through Canada with little in the way of
sensible change in the weather across SE Idaho. The ridge rebounds
Wednesday and amplifies Thursday ahead of an approaching Pacific
trough resulting in well above normal temperatures Wednesday and
Thursday afternoon. Once again, the models appear to be delaying the
onset of precipitation until Friday afternoon under a warm and
unstable SW flow aloft. Temperatures cool to near climatological
norms over the weekend in the wake of the passing trough. Huston




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