Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 291450

Area Forecast Discussion
National Weather Service GLASGOW MT
850 AM MDT THU SEP 29 2016

.SHORT TERM...for northeast through Sat...

Another quiet day expected and going forecast had things well in
hand. Did remove fog from Phillips County for this morning though.

Previous Discussion...
Upper ridge currently over Eastern Montana will move into Dakotas
today. This will turn flow aloft to the southwest for the
remainder of the week as upper trough in the Eastern Pacific digs
towards the west coast.

Warn and dry weather will prevail today as dry airmass remains
over the area. A shortwave trough in the SW flow aloft will move
through Eastern Montana tonight and into North Dakota on Friday.
Moisture will be limited to mainly south and east of the
Yellowstone River. Will mention chance/slight chance of showers
and thunderstorms in this area tonight and Friday morning.

Shortwave ridge in SW flow aloft will allow for dry weather Friday
Night and Saturday morning.

The upper trough/low will move inland across the Pacific NW on
Saturday. A wave from this system will move into Northern
Idaho/Western Montana during the day and bring a cold front into
Central Montana during the afternoon. Showers and thunderstorms
associated with this front could reach as far east as Phillips and
Petroleum Counties in the afternoon. Will mention a slight chance.
Otherwise, warm air will linger as highs approach 80. Forrester

.LONG TERM...Sat night through Thu...

Synoptic setup: long range begins with a ridge running northward
from the southern high Plains through the Dakotas and southern
Saskatchewan and Manitoba. A large trough sets over the coast of
northern California and The Pacific Northwest and moves inland
over British Columbia and western Alberta. An equal amplitude
ridge is directly behind that over the Gulf of Alaska moving up
through the state of Alaska and into the Arctic.

Saturday night through Sunday: a Shortwave will move through the
area bringing a brief burst of precipitation. Current best
guesses set around a couple hundredths to a quarter inch. directly
behind it will be a weak shortwave ridge with about 6 to 12 hours
of dry conditions before the next wave.

Sunday night through Tuesday: Trough to the west moves inland and
places northeast montana under a southern to southwest flow
pattern with multiple jet streaks and a tap on baja moisture. PoPs
are getting kicked up rapidly here as this system looks to produce
more moisture than the previous wave and may have a few
significant bursts similar to last week. temperatures will also
be reduced during this time with some models showing a canadian
tap late in the event.

Tuesday night onward: confidence in these periods has raised
slightly with the big three having a more fuzzy agreement than
previous. These periods will likely begin with colder temperatures
than those prior but weak ridging may move back in by late in the
week slowly ticking temps up. GAH


VFR conditions will continue today with high cloudiness moving
into the area this evening. East to southeast winds of 10 to 20
kts are expected today, especially in the afternoon. Maliawco




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