Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 120417

Area Forecast Discussion
National Weather Service Pocatello ID
917 PM MST Sat Nov 11 2017


Updated forecast to lower forecast temps tonight in many areas.
Excellent radiational cooling occurring and we are seeing temps
this evening already near forecast lows. Have adjusted down around
5 degrees or so, but perhaps not quite enough.



.PREV DISCUSSION... /issued 207 PM MST Sat Nov 11 2017/

SHORT TERM...Through Tuesday. Moist upslope flow is forecast to
persist across the Upper Snake Highlands through Sunday, and have
thus continued mention of a Snow Shower Chance and patchy Fog
from Island Park west through Monida Pass. This activity will
come to and end by late Sunday. Elsewhere, dry conditions are
expected through the remainder of the Weekend. The next Trough of
Low Pressure of Pacific origin is slated to move onshore across
Oregon and Washington Monday. A weak leading disturbance may
provide an isolated Snow Shower chance for the Sawtooths Monday
morning. Have backed off on the arrival of any heavier
precipitation across this area until Monday evening, however, as
model blend probabilities only indicate less than a 25% chance of
measurable precipitation across the Sawtooths Monday Morning.
However, by Monday Evening, there will be a good chance, if not
likely probabilities in seeing precipitation develop across the
Sawtooths. Elsewhere Monday, dry and mild conditions are expected
with breezy southerly winds across the `downslope corridor` and
for mid and upper slopes. Across the `downslope corridor` from
Burley through Pocatello and Fort Hall, high temperatures may
reach 60 degrees if enough Sunshine can be realized -- and with
only some thin high clouds currently forecast, 60 is not outside
of the realm of possibility. As we head through Monday night,
precipitation will continue across the Sawtooths and Pashimeroi
region with Snow levels 6,000-6,500 feet. 3 to 8 inches of Snow
are currently forecast across the Sawtooths through Monday night,
with the highest amounts relegated to upper West-facing slopes. By
Tuesday morning, a band of precipitation is expected to develop
from the Island Park area south and west across the Eastern
Highlands, the Interstate corridor and Southern Highlands.
Currently expecting Valley Rain and Mountain snow from this band
with Snow Levels around 6,000 feet elevation. Perhaps Snow will
fall low enough for some difficult travel at pass level. In the
wake of this system, a drying trend is forecast for the remainder
of Tuesday, with a few Snow Showers clinging to the Wyoming border
region. Breezy conditions are forecast to develop across the
Snake Plain, with wind gusts in the afternoon around 25 mph. AD/GK

LONG TERM...Tuesday night through Saturday.
In between systems Tuesday night and Wednesday and have dry
conditions Tuesday night but late Wednesday expect precipitation to
move back into the central mountains ahead of next Pacific system.
Will have rain and snow showers Wednesday night and Thursday with
snow level dropping to valley floors by Thursday.   Expect dry
conditions Friday again with precipiation from the next system on
westerly flow to begin influencing southeast Idaho next Saturday.
Expect above normal high temperatures Wednesday then cooling to
around normal Thursday and Friday warming again next weekend ahead
of the next system.

AVIATION...Low stratus persisted this morning at IDA and PIH but
has now lifted to VFR conditions at both places and expect trend to
continue through Sunday.   Expect widespread VFR at all TAF sites
with light winds under 10 knots tonight through Sunday.



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