Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Glasgow Montana
308 am MST sun Dec 11 2016
Short term...for northeast Montana...today through Tue...
Synoptic setup: zonal flow resides over the majority of the
Continental U.S.. a large polar airmass has dropped south and is centered
over eastern portions of the northwest territories with influence
stretched out east to west across majority of Canada and dipping
as far south as South Dakota. A large shortwave sets at the edges
of this airmass over souther British Columbia and Washington
Today through monday: center of the polar airmass to the north
will shift south into Saskatchewan which should push cold air advection through
the area. Meanwhile the shortwave over British Columbia will move
into central Montana and start generating over-running
precipitation. This should start generating a few weak bands of
snow showers across the far western zones during the alter
afternoon that will expand south and east across Garfield,
prairie, and Petroleum counties. By Monday morning the effects of
the shortwave should be exiting and snow across southern zones
should be diminishing. Snow totals may be about 1 to 3 inches
across a 30 hour time span. Windchills also appear to be of some
concern with winds occasionally rising above 10 mph and wind chill
reaching 25 below.
Monday night through tuesday: as cold high surface pressure
settles into central Montana and stabilizes out the atmosphere
conditions should become dry with partially clearing skies. The
strong inversion that develops will still call for hanging stratus
clouds at random. Gah
Long term...Tue night through sun...
Arctic high pressure and northwest flow aloft will be over eastern
Montana Tuesday night and Wednesday with cold and dry weather.
A shortwave ridge moves through the forecast area Wednesday night
and Thursday morning.
Then, a storm system moves inland from the Pacific on Thursday
and moisture ahead of the system moves into eastern Montana
Thursday afternoon and evening. Northeast Montana will be on the
northern edge of the moisture with this system.
A reinforcing Arctic cold front drops south out of Canada Thursday
night and Friday morning. Highs will struggle to make it to zero
on Friday. Meanwhile, the main part of the storm system is
forecasted to move through the central rockies and Wyoming. Will
mention a chance of snow as models differ somewhat as to how far
north the moisture will be with this system.
Arctic high pressure builds into eastern Montana Friday night and
Saturday with dry and bitter cold weather. The bitter cold will
continue on Sunday with northwest flow aloft. Forrester
Synopsis: a cold front is expected this afternoon and tonight.
The front could bring light snow to the taf sites tonight followed
by gusty northwest winds on Monday.
Weather/cig/vis: a mix of low and mid level clouds are expected this
morning. Widespread low clouds are expected tonight behind the
Flight category: VFR with areas of MVFR today. Widespread MVFR
ceilings expected tonight and Monday.
Winter Weather Advisory from 11 am this morning to 11 am MST
Monday for central and southeast Phillips...Garfield...
Wind Chill Advisory from 11 PM this evening to 5 PM MST Monday
for central and southern valley...Daniels...Dawson...eastern
Roosevelt...McCone...northern Phillips...northern Valley...