Wind Advisory 11, NWS Missoula, MT

921 
WWUS75 KMSO 172354
NPWMSO

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE MISSOULA MT
454 PM MST MON FEB 17 2014

IDZ007-180100-
/O.EXP.KMSO.WI.Y.0011.000000T0000Z-140218T0000Z/
OROFINO/GRANGEVILLE REGION-
354 PM PST MON FEB 17 2014

...WIND ADVISORY WILL EXPIRE AT 4 PM PST THIS AFTERNOON...

THE WIND ADVISORY WILL EXPIRE AT 4 PM PST THIS AFTERNOON. 

* LOCATIONS IMPACTED INCLUDE...CAMAS PRAIRIE...GRANGEVILLE AND 
  VICINITY...GREER GRADE

$$

Area Forecast Discussion...UPDATED
National Weather Service Missoula MT
829 AM MST Mon Feb 17 2014

.UPDATE...Upgraded the Lower Clark Fork Region to a winter storm
warning, specifically for Lookout Pass.

&&

.DISCUSSION...Very heavy snow has been observed on the camera up
at Lookout Pass. Snowfall rates up to 2 inches per hour are
possible through this afternoon, which will cause dangerous
driving from Haugan to Lookout Pass. Therefore the winter weather
advisory for this area has been upgraded to a winter storm
warning. Across northwest Montana, both mountains and valleys will
continue to receive accumulating snow through the morning. As a
cold front approaches this afternoon, widespread snow showers will
develop and cause periods of reduced visibility due to blowing
snow area wide. Winds could become quite gusty with any showers.
Additional winter weather headlines may be necessary, so please
stay tuned.

&&

.AVIATION...KGPI can expect to see ceilings and visibility
significantly affected by snow starting at around 17/1600z and
continuing through much of today. Showers will be in the vicinity
of KMSO, KSMN and KBTM throughout much of the day with obscured
terrain becoming common across the region today and tonight. Gusty
winds will develop this afternoon at KBTM with a northwesterly
wind shift forecast to occur this evening due to a frontal
passage. Gusts to 30kts can be expected.

&&

.PREV DISCUSSION... /ISSUED 351 AM MST Mon Feb 17 2014/

DISCUSSION...Snow has developed across northern portions of the
Idaho Panhandle and if satellite signatures are to be believed,
likely also across far northwest Montana early this morning.
This precipitation will gradually work its way across the
Northern Rockies today with widespread mountain snowfall expected
to impact travel over area passes, while valley snow is to affect
commerce and transportation throughout northwest Montana. A wide
swath of Winter Weather Advisories are in effect for much of
Montana and Idaho which further detail the potential impacts.
Northwest Montana valleys are likely to be the hardest hit today
and tonight with generally 2 to 5 inches new snow accumulation
by Tuesday morning. Local areas (Yaak, Heron & Plains for example)
may see upwards of 8 inches during this time frame. Meanwhile
Lookout and Marias Passes will be the most significantly affected
passes as periods of heavy snow develop throughout the day,
falling at rates of 1 to 2 inches per hour at times and total
between 10 and 15 inches by Tuesday morning. Poor visibility will
also become an issue later this afternoon and tonight as a strong
cold front pushes through the area and produces some blowing snow
over the higher terrain and passes.

There will likely be a lull in the activity on Tuesday morning
with perhaps even a few breaks in the clouds lasting into Tuesday
afternoon. However this will be short lived as yet another storm
system is set to affect the region Tuesday night into Wednesday
morning. This next storm bears some similarities in trajectory to
the current system but it is also a bit faster to move through
the region and possess significantly less moisture so for right
now is expected to produce far less snowfall. Showery, northwest
flow aloft will be left in its wake with colder air remaining in
place.

The weather pattern is still on track to transition to a cooler,
northwesterly flow for Thursday. The weather system forecast to
pass on Thursday will be cooler with lower snow levels than the
disturbances lately, so snow is possible down to most valley
locations on Thursday.

High pressure will build over the west coast during the end of the
week and through the weekend. The high pressure placement will keep
a northwesterly flow over Idaho and western Montana with on and off
chances for snow through the weekend.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY until 8 PM MST this evening
     Bitterroot/Sapphire Mountains.

     WINTER STORM WARNING until 5 PM MST this afternoon Lower Clark
     Fork Region.

     WINTER WEATHER ADVISORY until 5 PM MST this afternoon
     Flathead/Mission Valleys.

     WINTER WEATHER ADVISORY until 5 PM MST this afternoon West
     Glacier Region.

     WINTER WEATHER ADVISORY until 5 PM MST this afternoon
     Kootenai/Cabinet Region.

     WINTER WEATHER ADVISORY until 5 PM MST this afternoon
     Potomac/Seeley Lake Region.

ID...WINTER WEATHER ADVISORY until 7 PM PST this evening Northern
     Clearwater Mountains...Southern Clearwater Mountains.

&&

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