Area Forecast Discussion
Issued by NWS Pocatello, ID

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094
FXUS65 KPIH 200925
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
325 AM MDT Wed Sep 20 2017

.DISCUSSION...This morning, SE Idaho is starting out cold but
relatively quiet. Some cloudiness is noted over the mountains, but
the radar is clear. As the day progresses, this will change and
precip is expected to develop over the Central Mountains and
advance eastwards. At the same time, another windy day is in store
for today with winds forecast in the 25 to 35 mph range across the
Snake Plain (an upper Snake Highlands). A Wind Advisory has been
issued as a result. A mix of rain and snow is expected in the
Central Mountains, with the snow line around 8000 to 8500 ft. This
will drop going into Thursday with the snow levels dropping to
6000 ft. Attention turns to a developing line of expected showers
(both rain and snow) extending from Burley to Driggs later today
and meandering in this general vicinity through late Thursday. As
a result, decent precip amounts are probable in these areas. It
would be worth paying attention to forecasts in these areas if you
are invested in any outdoor activities or will be traveling.
Temperatures Friday, Saturday and Sunday mornings will be at the
freezing mark across the Snake Plain, and freeze warnings may be
issued. Looking at the weather pattern over the weekend and early
next week, there are no significant changes to the overall trend.
An upper closed low is forecast to meander over Idaho late in the
week and over the early half of the weekend before progressing
eastward. This will bring precip to the area before exiting. NP/KB

&&

.AVIATION...Another upper-level disturbance pivoting around a large
low pressure system will impact the area today, driving the next
cold front through the region. As a result, precipitation will be on
the increase through the day, first at KSUN, but expanding to the
other terminals with time. MVFR conditions expected in the
precipitation, which is expected to fall as -RA at the terminals,
although some -SN will be possible initially this morning at KSUN.
Other concern will be increasing west/southwest winds with the
frontal passage. Strongest winds will impact KPIH and KIDA, with
sustained speeds around 25-28 KTS and gusts of 35-40 KTS anticipated
late this morning and afternoon. KB

&&

.FIRE WEATHER...An expansive upper-level low pressure system will
continue to dominate the weather pattern for the remainder of the
week into the weekend. A disturbance pivoting around the broader low
pressure system will approach the area from the PacNW today, driving
another cold front through. This will bring a return of mountain
snow and valley rain today, following the brief break in
precipitation over much of the area overnight. West/southwest winds
will also crank up today with the frontal passage, with speeds
expected to reach 25-35 mph with gusts around 45 mph over portions
of the Snake Plain, Upper Snake Highlands, and higher ridgetops in
the Central Mountains. Relative humidity levels will remain elevated
as temperatures remain well below normal, precluding any critical
fire weather conditions despite the gusty winds. Intermittent
precipitation chances will continue across the area through Friday
as the upper-level low pressure system lumbers across the area.
Winds will be notably lighter after today. Precipitation chances
will decrease by this weekend and mainly be confined to shower
activity over the higher elevations as the the low pressure system
begins to open and shift east. Mainly dry conditions are then
anticipated early next week as high pressure builds along the West
Coast. Temperatures remain very cool by late September standards
through the weekend. We will see some moderation early next week,
but still remaining below normal. KB

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 10 AM this morning to 7 PM MDT this evening
for IDZ019>021.

&&

$$



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