FXUS65 KGGW 202028

Area Forecast Discussion
National Weather Service Glasgow MT
228 PM MDT Fri Oct 20 2017

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

An upper-level trough and cold front sweep across the Northern
High Plains this evening. As the surface trough moves out ahead of
the front, the pressure gradient tightens to generate strong wind.
In addition, the colder air behind the front will produce
scattered rain showers, but not much QPF. Wind will be westerly
at around 20-30G40kt. Due to the wind a Lake Wind Advisory is in
effect for Fort Peck Lake.

Frontal timing places the front near US Hwy 191 around 3 PM today,
near Hwy 24 near 6 PM, Hwy 13 near 8 PM, and Hwy 16 near 10 PM.
The expected light rain showers should be around 6 hours past this
frontal timing. Accumulations will be light if any at all.
Overnight temperatures will run in the 40s & upper 30s.

Wind continues, veering more to the northwest, through Saturday,
as the main trough axis and energy moves over NE Montana, another
similar round of light rain showers is expected, mainly near and
north of Hwy 2. Wind strength is expected slacken by 00Z when the
Lake Wind Advisory ends. With the push of much cooler air, highs
Saturday should become very close to seasonal norms.


.LONG TERM...Sat night through Fri...

Sunday will be another windy day as a jet from an upper
disturbance reinforces a strong surface breeze. The GFS is showing
30kt surface wind with a 50kt 700mb wind above that could generate
strong gusts, especially over higher terrain. A Lake Wind
Advisory is certain, but other wind headlines are possible as we
get closer to Sunday. Wind may remain strong enough to keep the
Lake Wind Advisory going through Monday as wind becomes more
northwesterly. Also of note in the extended is the cold front
dropping south through Northeast Montana on Wednesday bringing a
cold north wind and a chance for precipitation. Whether it's rain
or frozen will depend on timing. Used FB through Wednesday.


Previous discussion -
Saturday night through Monday night, weak high pressure returns to
the area. Some isolated showers will be possible but will be of
little to no impact. Of greater concern will another period of
strong and gusty winds Sunday through Monday as the weather
pattern establishes a tight pressure gradient and strong jet
stream over our region. Another Lake Wind Advisory will likely be

Tuesday into Wednesday, a warming and drying trend returns to the
area thanks to high pressure from the southwest.

Wednesday night through Thursday night, a strong cold front pushes
through NE Montana from the Canadian Rockies, with freezing
temperatures returning to some locations.




Flight Category: VFR

Synopsis: The overall weather pattern changes this afternoon with
increasing clouds and a cold front. The vertical wind profile
will become strong with a rapidly changing pressure gradient. The
cooler temperature with the front will generate scattered light
rain showers for some terminal areas this evening.

Winds: Strong and gusty winds are expected behind the front and
will introduce crosswind concerns for north-south oriented runways
through Saturday. 10kt winds from the southeast today, will
gradually veer around and increase from the west later this
afternoon. The strongest winds of around 20-30G40kt of the TAF
cycle will be between 00Z this evening and 12Z Saturday morning.



Lake Wind Advisory until 6 PM MDT Saturday For Fort Peck Lake
for Central and Southeast Phillips...Central and Southern



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