Area Forecast Discussion
Issued by NWS Pocatello, ID

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668
FXUS65 KPIH 152018
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
118 PM MST Wed Feb 15 2017

.SHORT TERM...Tonight through Saturday. A storm system moving thru
the Pac NW today will begin to bring snow into the central mtns
toward Thu morn. The greatest accumulations will be on the west
and south facing slopes...as they catch the Pac moisture in the
southwest flow aloft. Snowfall amounts of 6 to 10 inches can be
expected above 6500 ft by Fri morn. Precip will spread across the
rest of the area on Thu...with rain in the valleys and mtn snow.
The eastern highlands can expect 1 to 4 inches. Some freezing rain
is possible Thu morn in the eastern Magic Valley and lower Snake
River Plain due to trapped cold air at the surface. Precip
diminishes somewhat on Fri as upper ridging builds in. This will
not last long...as another surge of Pac moisture moves northward
into the fcst area Fri night. The main impacts from this storm
will be on the south facing slopes of the central mtns where up to
a foot of snow may fall by Sat eve. The upper Snake highlands may
see 3 to 6 inches...with the eastern and southern highlands
receiving much less. Once again...the valleys will see mainly
rain. Hedges

.LONG TERM...Saturday night through Wednesday. The bottom line
heading into next week:  WET AND MILD!  We are looking for the next
batch of rain and mountain snow to push across eastern Idaho
Saturday night and Sunday morning. A cold front will bring an end to
precipitation briefly west to east during the day. Snow levels peak
Saturday night actually around 6500-7000ft (if not higher) before
dropping Sunday to 5500-6000ft.  They will remain about 1000ft
higher until Sunday evening across the southern and eastern
highlands. There should be quite a bit of moisture, although it
appears we may see any heavier amounts being widespread due to
showers vs steady precipitation. That`s not a 100% lock but there
are indications that this could happen. The higher totals for snow
and rain should extend from around Island Park back across the Arco
Desert and Magic Valley, extending into the central mountains from
around Lone Pine back through Hailey and Sun Valley. Those areas
could see 7-14" of snow at/above 6500ft, with 2-5" inches for other
mountain ranges. Once you get to around 6000ft and lower, little to
no snow is forecast. If you look at rain/melted snow numbers and
follow the same pattern, 0.75-1.30" is possible and 0.40-0.70"
possible elsewhere. The models still are struggling with the timing
of the next storms for Monday through Wednesday at this point. Keyes

&&

.AVIATION...VFR Weather will continue through early tomorrow
morning even with an increase in clouds. We will see the chance of
rain and snow shift across eastern Idaho through tomorrow. The
current trend is VCSH to develop around KSUN after midnight, then
rain (perhaps a mix early on) around 14z. For now we kept VCSH out
of the other TAFS sites until the afternoon, although it`s possible
we could see KBYI earlier. Depending on the timing, there COULD be a
brief period of freezing rain when it starts. Otherwise, we will see
rain at the KPIH, KIDA and KDIJ when it begins.  We are looking at
most like dropping into MVFR weather, although we could see it drop
to IFR due low ceilings and heavier rain.  Keyes

&&

.HYDROLOGY...The Portneuf River at Pocatello continues to
fall...and should not be a threat for a few days. The river is
expected to rise above flood stage again next week due to forecast
rain and snowmelt. Sheet flooding remains a threat across the rest
of the low elevation areas...which may worsen due to additional
precip thru the weekend. Hedges

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 5 AM Thursday to 5 AM MST Friday
for IDZ018-031.

&&

$$



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