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Area forecast discussion 
National Weather Service Pocatello Idaho
213 am MST Wednesday Nov 25 2015

Short through Friday night. WV/infrared imagery showing
upper low has shifted southeast and is currently over northwestern
Nevada. Significant forcing is causing rain/snow over southwestern
Idaho. Models are suggesting a cold front will strengthen as it
crosses from Nevada into Utah later this morning with a band of heavy
snow directed right at the eastern Magic Valley and south Central
Highlands. NAM intensifies precipitation along a band further north along
the Montana border late this morning...also suggested by our local WRF
model. Expecting snow amounts of 4 to 6 inches across the southern
half of the central mountains across to Island Park. Main brunt of
system will impact the southern half of our forecast area
beginning with Burley and Shoshone early this morning...shifting
east across zones 22 and into zone 23...24 and 25 later this
afternoon. Accumulations above 6000 feet could see 10 to 14 inches
through tomorrow afternoon. Concern is also for strong down-valley
winds developing across the snake plain this morning...further
complicating things with the potential for blowing snow. Models
push cold front eastward throughout the day...but it seems to
stall along the Wasatch Range while moisture continues to wrap
around the middle-level low through Friday. Models suggest tapering
off the precipitation as much of the dynamics shift to the east.

Long term...Friday night through Wednesday. Models again having a very
difficult time through the extended. Upper low lingers then meanders
around the Great Basin before lifting toward the northern plains
Sunday. GFS and European model (ecmwf) differ on timing and placement of the low with
resulting differences in quantitative precipitation forecast and temperature expectations. GFS further
north and slower than the European model (ecmwf) thus warmer and wetter. Solutions
further complicated by handling of energy coming into Pacific coast
Monday. GFS again further north/faster and much wetter than the
European model (ecmwf) with hints at an atmospheric river type event pushing into the
coastal states and reaching east Idaho by Wednesday. Opted toward a
blend of both solutions through the extended which remains close to
previous forecast. Dmh

Aviation...even in the short term there is still quite a bit of
uncertainty with the unfolding of this event over east Idaho. Quite
a bit of model spread on the start of the precipitation at each of
the terminal sites though they are seeming to favor onset shortly
after sunrise at kbyi/ksun and a middle-afternoon start for kpih/kida.
Temperature profiles close to the surface will be tricky for determining
snow/rain for kpih but still favor snow at all terminals through the
event. Northerly gradient continues to strengthen through the day so
blowing snow remains a possibility especially kida through the
afternoon/evening. Overall trend favors conditions lowering through
the day to at least MVFR but likely IFR at all sites once the snow
does settle in. Do not expect to make significant changes to current
terminals other than adjusting for latest timing expectations. Dmh

Pih watches/warnings/advisories...
Winter Weather Advisory from 5 am early this morning to 11 am
MST Thursday for idz019>021-023>025-031-032.

Winter Storm Warning from 5 am early this morning to 11 am MST
Thursday for idz017-022.



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