Area Forecast Discussion
Issued by NWS Glasgow, MT
FXUS65 KGGW 091604 AAA
Area Forecast Discussion...UPDATED
National Weather Service GLASGOW MT
904 AM MST Fri Dec 9 2016
.SHORT TERM...for northeast Montana...today through Sun...
Quite a spread in temperatures this morning at 8 AM, with 16 below
at SDY to 5 below at GGW to 0 at QWT. Have a hazard this morning
of wind chills but winds are light and only approaching 10mph in
GGW. Will leave the wind chill advsry up this morning while
temperatures remain frigid. Combined radar imagery shows a wide,
solid band of weak echoes that are producing light snow from GTF
to BIL. This band is now moving into our southwest zones and
should spread southeast today. This may keep our northeastern
zones dry. Otherwise, low clouds have brought low ceilings across
the area, much of the cloud cover being generated by very cold air
over a relatively warm Fort Peck Lake.
No significant edits. Main update was to include latest 12Z
Previous Discussion -
Wind Chill Advisory is has been expanded eastward for this morning
as the temperatures have fallen in the river valleys. This is
resulting in wind chills down to 30 below zero.
Arctic high pressure will continue to drift eastward today. While
the cold trof will maintain its influence over the northern
plains, moist westerly flow off the Pacific will spread across the
Rockies over the weekend. As the moisture rides over the cold air
in northeast Montana, snow is expected to develop late tonight
into Saturday. Amounts look to be around 1 to 2 inches focusing
along the Missouri River.
Weak high pressure and moist jet shifting south should shut off
the snow by Sunday. Ebert
.LONG TERM...Sun night through Fri...
Synoptic Setup: long range begins with zonal flow over most of the
CONUS. Coldest air over the northern hemisphere is centered over
northern Saskatchewan with the airmasses influence extending south
into central Montana. A second wave of extreme cold air has
jostledout of Siberia and is moving its way across the arctic
ocean just north of Alaska.
Sunday night through Monday: A little bit of pacific moisture
passing through from the zonal flow will override the new cold
airmass moving through the region to generate stratiform snow
showers during these periods. Total snow will be light with maybe
1 to 2 inches.
Monday Night through Thursday: center of the first airmass will
slide southeast and then movie into Quebec. Northeast Montana may
warm slightly moves west but slightly is a relative term with
maybe some highs in the teens rather than single digits. Meanwhile
the second wave of arctic air will roll down the high plains of
alberta and knock on the international doorstep.
Thursday night onward: Some models are taking the second wave of
cold air and rather than kicking it eastward, centering it over
montana. This will plunge temperatures when combined with any
previous snowfall into some of the lowest seen thus far this
year. Confidence here is moderate. GAH
SYNOPSIS: Solid patches of low stratus decks are floating around
the region this morning and periodically impacting the terminals.
These patches are big enough to hold for a couple hours and then
give way to clear skies. Will have to handle them with amends in
and out of BKN/SCT 015.
By the end of the cycle, snow showers will present themselves
with the entrance of a shortwave Saturday morning.
WINDS: Light Easterly winds will increase to 10-15 kts this
evening and sustaining through Saturday.
Wind Chill Advisory until noon MST today for Central and
Southern Valley...Dawson...Eastern Roosevelt...Garfield...