Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 172018

Area Forecast Discussion
National Weather Service Pocatello ID
218 PM MDT Sat Mar 17 2018

.SHORT TERM...Tonight through Monday. Snow showers continue across
eastern Idaho. Snow amounts appear to have come in a little under
the forecast across portions of the central mountains, while the
opposite happened across portions of the south-central highlands
along/west of I-15 into the Lower Snake Plain. The focus of snow
this afternoon and this evening is still in areas where we have
now. Additional snow fall is expected (only 1-3 inches) but
likely enough that it will add to snowfall especially in the
mountains and any impacts there, as well as we could see slick
roads as it turns colder tonight. The other main focus of snow has
shifted into the eastern highlands, with additional pockets/bands
of showers behind it across the Plain and southern highlands.
There is still the potential for an evening thunderstorm, but no
enough to keep it mentioned in the text forecast. Overnight, we
should see showers end for the most part everywhere except the
central mountains and along the Montana border. The concern is
the could be some stratus develop with all of the moisture around
and snow already melting in some locations. Will there be fog? We
aren`t currently expecting it, but this pattern is certainly
conducive for at least patchy fog.

The low finally shifts over eastern Idaho Sunday. Showers will
persist in the central mountains and along the Montana border
under the core of the storm. The models for the afternoon. One
camp develops showers over the rest of the region, while the other
has minimal to nothing. We went with the "showery" scenario for
all of eastern Idaho. There is just too much moisture and likely
some instability to kick off showers just about anywhere. We
aren`t expecting thunder, but it`s March and we sometimes get a
couple of strikes in this situation. Monday should be drier
overall ALTHOUGH showers are still possible mainly in the
mountains. We also will have to see how much clearing and how
light the winds are Sunday night. Where we get any of that
maximized, we would be surprised to see fog and stratus. Stay
tuned. We should starting warming up a bit heading into next week.

.LONG TERM...Monday Night through Saturday. The extended period
will remain somewhat unsettled as the intermountain remains under
the influence of a moist southwest to west flow. A cutoff low off
California near 140W will weaken and move onshore
Wednesday/Wednesday night as an open trof as yet another upper low
drops southward along 130W off the Pacific NW coast. This will
bring another round of precipitation into SE Idaho for Wednesday
and Thursday. The upper low along the Pacific NW coast will slowly
shift east and therefore keep SE Idaho under moist southwest flow
and thus the continuation of a threat of showers for late in the
week into Saturday. Temps look to be on the warm side of
climatology Wednesday and Thursday and then cool slightly with the
incoming low Friday and Saturday. Temperature trends will likely
result in mainly rain in the Snake Plain for midweek and a
transition to snow later in the week. DSH


.AVIATION...Improving conditions at most terminals this afternoon as
an upper low over SW Idaho gradually shifts east. The upper low
weakens and shifts east overnight so will see some lingering snow
showers over higher elevations into the evening hours.  Vis in
showers likely to be 1-2 miles or less and CIGS bouncing between
VFR/MVFR to IFR for the rest of tonight.  Lingering clouds for
Sunday with CIGS VFR to MVFR. DSH


Winter Storm Warning until 6 AM MDT Sunday for IDZ018-031-032.

Winter Weather Advisory until 6 AM MDT Sunday for IDZ019.


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