Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 222044
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
144 PM MST Wed Nov 22 2017

.SHORT TERM...for northeast Montana...tonight through Thu...

Surface analysis shows a cold front across the northeast zones and
drifting south this afternoon. Temperatures have reached the 50s
and 60s as far north as Highway 2 this afternoon. But much colder
air just to our north is moving south and will especially cool off
the northeast zones tonight.

But another push of a Pacific airmass will take place from the
west. A strong jet stream from the southwest will develop into
Alberta tonight with a surface low expected to move into Sask
Thanksgiving afternoon. This airmass overriding the cooler air at
the surface looks to create fog or low clouds over the northern
and some central zones. The warm air aloft should reach the
surface thanks to increasing sunshine and a downslope
compressional mechanics of a SW wind on Thanksgiving.
Temperatures will be tricky since the day begins a sharp
temperature inversion, similar to today. Record highs can expect
to be broken in most places.

Late in the day, strengthening mid-level winds approach the area
and with some mixing, strong winds may occur in SW Philips County.
A High Wind Watch has been issued. TFJ

.LONG TERM...Thu night through Wed...

Models are starting to agree with the system on Monday a bit. The
ECMWF has weakened the system a bit while the other models have
brought some energy to the area, but mainly keep most of the qpf
to our south. Precipitation type continues to show rain changing
to snow with any accumulations greatest in the SE zones.

Otherwise, cold front moves through late Thursday with 850 mb
winds 50-55 kts and another chance for high winds in SW Phillips
county. A High Wind Watch has been issued for Thursday afternoon
through Thursday Night. TFJ

Previous Discussion...
Shortwave trof moving across western Canada will break down the
ridge and drag a cold front across Montana Thursday night. Enough
cold air advection, pressure rises and winds aloft, to generate
some strong wind gusts across northeast Montana overnight. Could
also see some light rain with the frontal passage.

Temperatures behind the front will cool from the near record
values of Thanksgiving day, but will still be above normal with
the flatter zonal flow off the Pacific early in the weekend. Ridge
will slowly rebound with temperatures warming again into the 50s
or lower 60s by Sunday.

Ridge again breaks down early next week with trof moving into
western Canada. Models also bringing a portion of the trof through
the Great Basin. With the slight split in the trof, precipitation
chances are increased for northeast Montana. Canadian portion of
the trof is expected to pull cold air southward, then the southern
portion lifts moisture across the cold air. The EC is much more
agressive, and farther north, than either the GFS or CMC with the
precipitation, but expect to have temperatures drop closer to
normal. Ebert

&&

.AVIATION...

Flight Condition: VFR then MVFR/isold IFR late tonight.

Synopsis: Another warm front will move across the area late
tonight, this time developing fog for late tonight and early
Thursday. Visibilities may drop below 3sm. Conditions are expected
to improve by Thursday afternoon.

LLWS: With the strong winds at mid-levels and light winds at the
surface, LLWS will be a concern late tonight/early Thursday.

TFJ

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from Thursday afternoon through late Thursday
night for Southwest Phillips.

&&

$$

weather.gov/glasgow



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