Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 211622

Area Forecast Discussion
National Weather Service Pocatello ID
922 AM MST Sat Jan 21 2017

.UPDATE...No major changes to the forecast this morning. It still
appears the most of the precipitation will fall today across the
along and east of I-15 as well as the in the central mountains
from Stanley to Mackay to near Gilmore Summit. Amounts will be
light with still 1-3" for the southeast highlands. We could see
just a bit more on the peaks of the Bear River Range.  Keyes


.PREV DISCUSSION... /issued 344 AM MST Sat Jan 21 2017/

SHORT TERM...Today through Monday night. Expect lingering light
snow showers today as a weak trough exits the area. Expect less
than 1 inch of snow across the Snake river plain and the Central
mountains with 1 to 3 inches across the Eastern Highlands. The
Wasatch mountains may see slightly higher snow amounts.

A cold front moves through the area Sunday through Monday night.
Currently models are showing 2 to 5 inches of valley snow and 6 to
12 inches of mountain snow for the Central mountains, the Upper
Snake Highlands, the Caribou Highlands, the Wasatch mountains, and
the Eastern Southern Highlands. The Caribou Highlands and the
Wasatch mountains above 7500 feet could see 16 to 20 inches of
snow. A winter storm watch is in effect for the Central
mountains, Upper Snake Highlands, Caribou Highlands and the
Wasatch mountains Sunday AM through Tuesday AM. There is low
confidence with snow amounts across the Eastern Magic Valley and
the Snake River plain. On Sunday into Monday morning downslope
Southerly winds could raise snow levels even more reducing snow
amounts, particularly across the I-86 corridor from Pocatello to
Burley. Also, there is still uncertainty with wrap around moisture
and the potential for a convergence event Monday night into
Tuesday. TW

LONG TERM...Tuesday through next Saturday. Both the GFS and ECMWF
models show the upper low over Wyoming extending WSW across the
Great Basin will be slow to exit the region Tuesday while lingering
moisture remains over the region through Thursday supporting light
snowfall in a moist NNW flow. Drier conditions filter into the
region Friday and continue through Saturday as the flow aloft turns
NNE across the region as a ridge of high pressure builds over the NW
coast. Temperatures should cool some under clearing skies Friday and
Saturday and this is reflected in the statistical guidance with
colder overnight lows. Huston

AVIATION...Early morning satellite imagery was showing a negatively
tilted trough over the region with weak embedded impulses lifting NE
across the Great Basin and attending bands of snow (MVFR/IFR
CIGS/VIS). Numerical models continue to support this ongoing
activity through early afternoon with some clearing aloft overnight
as the next storm system takes shape off the coast and a flat ridge
builds over the ERN Great Basin. Model cross sections suggest that
low level moisture will likely get trapped under the shallow ridge
promoting areas of low stratus and/or fog (IFR CIGS/VIS) at select
terminals (primarily KPIH, KIDA, and KDIJ). The models are also
showing some low level moisture returning to KSUN towards 12z/5am
Sunday morning but this looks a little too aggressive given the
pattern. Huston


Winter Storm Watch from Sunday morning through late Monday night
for IDZ018-019-023-025-031.


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