Winter Storm Warning 12, NWS Pocatello, ID

993 
WWUS45 KPIH 080930
WSWPIH

URGENT - WINTER WEATHER MESSAGE
National Weather Service Pocatello ID
230 AM MST Wed Mar 8 2017


IDZ018-031-081030-
/O.CAN.KPIH.WS.W.0012.000000T0000Z-170308T1800Z/
Sawtooth Mountains-Big and Little Wood River Region-
Including the cities of Stanley, Clayton, Hailey, Ketchum, 
and Bellevue
230 AM MST Wed Mar 8 2017

...WINTER STORM WARNING IS CANCELLED...

The National Weather Service in Pocatello has cancelled the
Winter Storm Warning. 

Impacts to the regions are currently minimal this morning and are
expected to continue in this way therefore this warning is being 
allowed to expire. However, light snow with accumulations of 1 to 
3 inches are possible this morning across the Sawtooth Mountains 
and Big and Little Wood River areas. Blowing snow is also possible
throughout the day.

$$

IDZ019-082200-
/O.EXT.KPIH.WW.Y.0022.000000T0000Z-170310T2100Z/
Upper Snake Highlands-
Including the cities of St. Anthony, Ashton, Island Park, Driggs,
and Victor
230 AM MST Wed Mar 8 2017

...WINTER WEATHER ADVISORY NOW IN EFFECT UNTIL 2 PM MST FRIDAY...

* IMPACTS...Heavy snow, blowing snow and drifting snow will create
  reduced visibilities and difficult driving conditions,
  especially for those driving high profile vehicles.

* TIMING...Snow showers through Friday afternoon with heavy snow
  likely on Thursday. Winds increasing this afternoon and
  persisting through the evening. 

* SNOW ACCUMULATIONS...4 to 8 inches up to 12 inches above 6000 feet
  along and east of Highway 20, including Pine Creek Pass. 1 to 3
  inches in the lower valleys.
 
* CONFIDENCE...Medium confidence in snow amounts. High confidence
  in winds. Medium confidence in timing.

* LOCATIONS...Dubois, Pine Creek Pass, Targhee Pass, Island Park,
  Victor, Raynolds Pass, Tetonia, Spencer. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A winter weather advisory means that periods of snow and drifting
snow will cause primarily travel difficulties. Be prepared for
snow covered roads and limited visibilities, and use caution
while driving.

&&

$$

Area Forecast Discussion
National Weather Service Pocatello ID
236 AM MST Tue Mar 7 2017

.SHORT TERM...Today through Thursday night. Quasi-zonal flow
setting up with upper jet shifting northward into southeast Idaho.
There seems to be no distinct shortwaves, and models are generally
keeping precip in upslope-favored areas--mainly the Central
Mountains and Southeastern Highlands. Given the proximity of the
upper jet and strong mid-level flow, surface winds will be brisk,
though guidance keeps speeds just below advisory level. GFS MOS
nudges winds just above advisory tomorrow afternoon, but not
enough confidence to run with it just yet. Broad upper ridge
builds across the area Thursday and Thursday night which will help
bring warmer temperatures into the region, with highs in the 50s
reaching the Pocatello area. This will also lead to more rapid
melting of the snowpack and bring potential flooding concerns.
Hinsberger

.LONG TERM...Friday through Tuesday night. Once again...models are
at odds with each other. The ECMWF favors a drier extended period
while the GFS is wetter. Models start out in agreement with moist
zonal flow on Fri. This results in light precip across the area...
and favoring the upslope regions of the central mtns and eastern
highlands. The airmass is mild...so snow levels will be relatively
high. Both models build low amplitude upper ridging over the region
resulting in drier conditions Fri night and Sat. Sat night is where
things go south. The GFS maintains a moist zonal flow with minor
waves...thus precip. The ECMWF maintains ridging...and dry
conditions into Mon. The GFS eventually catches up...reducing precip
Sun night and Mon. They are both on board with a new trof moving
into the Pac NW on Tue for another round of precip. The problem
area is Sun. Since both models have been remaining firm on their
solutions...will have to go with middle ground and carry some
precip over the fcst area on Sun. Hedges

&&

.AVIATION...Strong westerly flow aloft will continue to pump Pac
moisture into the region thru tonight. This will result in periods
of light snow with ocnl low cigs/vis. Greatest impact will be at
KSUN and KDIJ...and mainly tonight. Features are nebulous...so
timing will be challenging. Strong southwest winds will continue in
the Snake River Plain thru tonight. Hedges

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&