Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 300928

Area Forecast Discussion
National Weather Service Pocatello ID
228 AM MST Wed Nov 30 2016

.SHORT TERM...Today through Friday night. A return to light snow
is expected to commence this morning as moisture begins to spill
back into SE Idaho. Light snow showers are expected to begin
across the Continental Divide region east through Island Park and
southward towards Palisades by around sunrise this morning, with
activity increasing with coverage and intensity through the day.
By this evening, snow showers are expected to begin across the
Central Mountains and down towards Bear Lake and City of Rocks,
with this status quo continuing through the night. Snowfall
amounts of generally 1-3 inches are expected across the above-
mentioned areas through Thursday morning, with possibly higher
totals around Island Park. The heaviest and most impactful
snowfall is expected to begin Thursday morning over the Upper
Snake Plain and Divide region southward towards Palisades as a
stout, compact disturbance enters the region. Snowfall may be
heavy at times across these areas Thursday morning. This snowfall
will slide southeastward through the day, with the heaviest
snowfall impacting the area from Palisades south to the UT border.
Can`t rule out a lightning strike with this activity as well as
some instability will be realized. Treacherous travel certainly a
concern Thursday across these areas and travelers should
anticipate winter driving conditions.

Snow is expected to gradually wind down Thursday night. Snowfall
totals of an inch or two will be possible across the I-15
corridor, with as much as 6"+ possible around Pine Creek Pass and
around the Island Park area. Dry conditions expected to build into
the area Friday, with some patchy morning fog possible. The next
disturbance will begin to spread snow back into highland areas by
late Friday night. Temperatures will hover around climatological
averages through the period. AD/Huston

.LONG TERM...Saturday through next Wednesday. A shallow ridge
remains positioned along the west coast while moisture spills over
the ridge into the NRN Rockies resulting in light snowfall favoring
NW upslope regions in the CNTRL and NE mountains. The GFS and ECMWF
are in lock step driving a Pacific trough into the NW states Sunday
resulting in increasing winds and a quick shot of moderate snowfall
from the passing system which exits the region by about Monday
morning. The models diverge a little on the track of secondary
energy digging into/through the region Monday/Tuesday and thus
have maintained at least a slight chance/chance mention of snow
for the start of the week. We may see a brief period of drying
Tuesday night into Wednesday as a transient ridge builds into the
region ahead of the next Pacific storm system. Here the models and
a similar idea they just differ fairly significantly on the
amplitude of the ridge building into the area Wednesday which has
a direct impact on the potential for light over running precip.
Opted to split the difference here. Daytime temps will run near
normal over the weekend but take a digger falling well below
normal early next week. Huston


.AVIATION...A transient ridge builds across the region this morning
and the models appear to be indicating lingering stratus/MVFR CIGS
across the NE highlands/Upper Snake River Plain possibly impacting
the KDIJ and KIDA terminals. By early evening, the next Pacific
trough begins to dig into the region with attending moisture/snow
overspreading the terminals overnight. Expecting to see CIGS fall
into IFR categories at KPIH, KIDA and KDIJ overnight with temporary
LIFR CIGS and VIS in snow. KBYI may see CIGS waffling between MVFR
and IFR while KSUN may see some benefit from downslope/NW flow
developing after midnight. Huston



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