Area Forecast Discussion
Issued by NWS Glasgow, MT

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748
FXUS65 KGGW 192102
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
302 PM MDT Tue Sep 19 2017

.SHORT TERM...for northeast Montana...tonight through Wed...
Isolated showers continue across the area this afternoon along
with breezy west winds. In fact, as winds have been a little more
persistent, a Lake Wind Advisory has been issued for Fort Peck
Lake through early this evening.

High pressure will make for dry weather conditions tonight across
northeast Montana with clearing skies. As Wednesday approaches,
the surface high will push downstream as an upper trough
developing over the western U.S. drives upper level southwest flow
across eastern Montana. This will once again bring a chance for
scattered showers into the area, though rainfall amounts look to
be light at this time. Maliawco

.LONG TERM...Wed night through Tue...

Blended current forecast with 12z model runs. Removed mention of
snow for Friday Night/Saturday morning. TFJ

Previous Discussion...
Synoptic Setup: Long range begins with a long strong of southwest
flow running from central California through Wyoming the Dakotas
and southern Manitoba. Directly behind it a large trough stretches
from northern California through the Pacific Northwest, Alberta,
and northern Saskatchewan. Behind that a large ridge resides south
of the Aleutians and moving into the Gulf of Alaska. The coldest
air of the northern hemisphere sets over the Arctic Ocean just
north of the Alaskan North Slope.

Wednesday night through Thursday: Frontal boundary across the
region will not move much as the trough behind it gains strength.
This should keep temperatures up in the 60s for highs. Skies
should also be mostly cloudy to overcast due to the pacific
moisture stream by aloft with only a slight chance for rain
showers.

Thursday night to Friday night: Surface boundary will begin to
move bringing colder air into the region form the north. This drop
in temperatures should squeeze out more QPF during these periods.
With overnight low continuing to drop would not be surprised if
by Friday night a mix of snow and rain is possible for any
showers.

Saturday through Sunday: Bulk of the trough will move through
during this time bringing the coldest temperatures. but with the
temps stabilized out showers should become progressively less.
Meanwhile, the Gulf of Alaska Ridge will move inland over British
Columbia.

Sunday night onward: RIdge will nose out over alberta spilling
over into a slight warming chinook that will press up against the
slow exiting trough. This should stabilize the atmosphere and
trend temperatures upwards during this time with current models
estimating the chinook to reach central Montana by Monday night.
GAH


&&

.AVIATION...
VFR conditions are expected tonight with diminishing shower
activity and winds decreasing to under 10 kts. Maliawco


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Lake Wind Advisory until 7 PM MDT this evening For Fort Peck
Lake for Central and Southeast Phillips...Central and Southern
Valley...Garfield...McCone...Petroleum.

&&

$$

weather.gov/glasgow



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