Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 111011

Area Forecast Discussion
National Weather Service Pocatello ID
310 AM MST Wed Jan 11 2017

.SHORT TERM...Tonight through Friday night. Early morning regional
radar and satellite imagery were showing widespread rain and snow
advancing east across the area ahead of a disturbance sweeping east
into the CNTRL Sierra. Models show the parent upper low remaining
positioned along the Oregon coast throughout the day as a secondary
circulation digs SE off the California coast today and tonight
effectively dragging the Pacific moisture feed south across Nevada
and Utah tonight. Ongoing moderate to heavy mountain snow will
continue across the CNTRL mountains this morning tapering off this
afternoon while ongoing heavy snowfall continues across the eastern
highlands. Within the Snake River Plain and ERN Magic Valley light
snow accumulations will be confined to areas north of Shoshone and
the Upper Snake River Plain with rain anticipated from Pocatello to
Burley along the I-86/84 corridor. In addition, only modest
accumulations are anticipated at elevations above 5500 feet MSL
across the South Central Highlands. Thus some fairly heavy handed
timing and areal adjustments were made to the going highlights. For
Thursday and Friday, the upper digs SSE through southern California
while associated moisture rotates north through Utah to the southern
Idaho border resulting in fairly dry conditions as cooler air from
the north dominates. The statistical guidance was showing colder
temperatures running into Friday and this seemed reasonable given
the flow regime. Huston

.LONG TERM...Saturday through next Wednesday. The weekend will bring
high pressure and a quiet weather period free from rain or snow.
Temperatures are expected to be cool in the low to mid 20s for highs
and single digits and pockets of subzero temperatures for lows. By
the start of next week a slow but gradual warming trend is forecast
Monday and Tuesday going into the mid to upper 30s by Wednesday as
the high shifts itself southeastward and low pressure approaches
from the west. A chance for snow will exist by Wednesday associated
with this low which may mix with rain due to increasing snow levels
at the same time at some locations. We will keep watching the
progression of this system as it nears next week. NP/MH

.AVIATION...Challenging ceiling and visibility forecast early on due
to rain and snow progression. IFR ceilings are anticipated this
morning with improvement forecast by the evening at PIH, BYI. SUN is
likely to break out this afternoon to MVFR or VFR. DIJ should stay
IFR or MVFR throughout the day. Visibilities are likely to be P6SM
most of the day with DIJ and SUN varying between 2 and P6SM this
morning due to snow and/or blowing snow. The remaining Snake Plain
sites should only see precipitation this morning or possibly a brief
light shower this afternoon. Wind speeds are expected to increase
out of the south or southwest this morning with gusts to 40 mph at
PIH, IDA and BYI. Winds are likely to sustain through evening at PIH
and IDA and improve overnight. Winds at BYI are expected to improve
during the late afternoon hours. NP/MH

.HYDROLOGY...Rising snow levels were noted Tuesday evening
resulting in rain in the lower valley locations early this morning.
The NOHRSC Snow Melt model was showing modest liquid production
mainly in the Burley area today while the remaining valley locations
showed little significant risk. However, given the uncertainty of
the snow levels and minor ongoing drainage issues, we opted to
continue the Areal Flood Warning for the valley locations across SE
Idaho. In addition, ice jam and avalanche debris issues continued
near Challis and Hailey, respectively and thus the Flood Advisories
were continued in those areas as well. Drier conditions follow
tonight through the end of the week and we anticipate dropping the
Areal Flood Warnings later this afternoon. Huston

Winter Weather Advisory until 3 PM MST today for IDZ022-032.

Winter Storm Warning until 3 PM MST today for IDZ018-031.

Winter Storm Warning until 11 PM MST today for IDZ023-025.

Winter Storm Warning until 4 AM MST Thursday for IDZ019.

Winter Weather Advisory until 11 PM MST today for IDZ024.

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