Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 220958

Area Forecast Discussion
National Weather Service Pocatello ID
258 AM MST Mon Jan 22 2018

.SHORT TERM...Today through Wednesday. We are still watching
today`s snow event trying to develop as it marches into eastern
Idaho. To be honest, not a lot has fallen to our west early on.
The forecast scenarios still show an enhanced band of snow setting
up from Oakley north through Stanley, although it may not get
started until around sunrise and commute time. Confidence isn`t as
high as it should be within such a short time period, but that`s
where we are at the moment. If we do get what is forecast, that
area within that band will see 1-3", perhaps locally higher around
Pomerelle and also in the Sawtooths. The WINTER WEATHER ADVISORY
for the Magic Valley stands through 11am for now. As the storm
spreads east today, the idea still is for lighter snow to occur,
especially where we are getting downslope early on along the 86
corridor and also into the southern highlands. Much of the Teton
Valley will be in the same boat, or in the case...sled. We are
also looking at upslope to enhance snowfall a bit across the far
Upper Snake Plain and Highlands. Where are thinking anywhere from
a dusting and inch or two farther east, and if we get some
upslope...then around 3 or just a bit more. Once again, confidence
isn`t the highest this morning. The chance of snow decrease
tonight, and should well east of the I-15 corridor into the
eastern highlands by morning. There is some hint still of a
convergence/upslope band forming north of Idaho Falls and Rexburg,
pushing into the Island Park and Teton Valley areas. There COULD
be another 1-3" there, other just very light snow remaining where
it continues to fall. There is the potential for stratus and
patchy fog across portions of the Snake Plain and southern
highlands late tonight and tomorrow morning, which we`ve included.
Otherwise, some occasional light snow remains possible through
Wednesday across the Upper Snake Highlands and central mountains.
Afternoon temperatures should remain at/above typical late January
numbers, in fact we should see many lower valley locations
topping 40 degrees Wednesday. Keyes

.LONG TERM...Wednesday night through Monday. Models remain in fair
agreement during the extended period. Precipitation expected to push
into the region Wednesday night, but main event still reserved for
Thursday. There are still some minor differences in depth and timing
between models and ensembles, but nothing significant enough to
force major changes to going forecast. Temperatures still appear to
be cold enough to support snow at all elevations as this system
drives through, and cold front still appears to be well timed for
late Thursday. Region remains under the influence of shallow trough
into early Saturday as main trough deepens into the Plains. Thus
unsettled and cooler conditions will continue. Stronger shortwave
pushes into the PacNW Sunday, but there`s quite a bit of difference
by this time in the model solutions, and the GFS is quite a bit
wetter than the ECMWF, though still favoring mainly higher
elevations and a drier Snake Plain/southern highlands. Most
solutions then favor transition of weak upper ridge across the
region on Monday. DMH


.AVIATION...Precipitation is moving into the region early this
morning, and ceilings/visibility is starting to lower in response.
Expect VFR conditions to deteriorate west to east, dropping to at
least MVFR with occasional IFR. Believe that KSUN/KBYI will likely
see worst conditions prior to 18Z, KPIH/KIDA between 15Z-21Z, and
KDIJ 21-06Z, largely coincident with passage of the upper level
feature/not quite a surface front. Winds pick up slightly behind the
main precipitation band this afternoon and evening. Overall effects
of this system should remain fairly weak. Expect some clearing
overnight, but may be shortlived as whatever moisture deposited
today helps feed development of stratus. DMH


Winter Weather Advisory until 11 AM MST this morning for IDZ017.


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