Area Forecast Discussion
Issued by NWS Glasgow, MT

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936
FXUS65 KGGW 221523
AFDGGW

Area Forecast Discussion
National Weather Service Glasgow MT
923 AM MDT Fri Sep 22 2017

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

Just refreshed some grids, expecting rainshowers over SW Valley
County and south to weaken over the next few hours. Thunderstorms
over North Dakota is a sign that some jet energy is moving north
and this could touch off some showers over the eastern zones.
Overall, going forecast was in good shape. TFJ

Previous Discussion...
Synoptic Setup: Southwest flow aloft runs from southern
California, through Utah and eastern montana, and into southern
Manitoba. A Large trough runs from right behind this from Nevada
through western Montana and into Alberta and Saskatchewan. Farther
west a large ridge has developed over the Gulf of Alaska.

Today: Southwest flow aloft has brought a second wave of moisture
and precipitation across the area this morning that should last
through roughly noon. Locations over the Petroleum Phillips and
Garfield counties may experience between a half to a quarter of an
inch of precip with the passage while most other locations will
be lucky to get even a tenth of an inch out of it. Precipitation
should shrink out quickly during the afternoon hours as mid level
jet support moves into southern Saskatchewan.

Tonight through Saturday: Another jet with support for weak
showers may pass over the far southwestern zones tonight but
rainfall totals will be minimal. Persistent light northern wind
should advect cooler air into the CWA overnight as well. With
little to no precipitation around on Saturday temperatures should
be a few degrees higher. GAH


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

Deep upper trof/low over the Great Basin over the weekend will
slowly lift northeast toward Ontario through next week. By the end
of the week a ridge is expected to return to the western states.

Upper trof over the region will keep temperatures below normal but
will see a slight warming trend through the period as the trof
translates eastward. Unstable airmass will result in occasional
showers, with temperature profiles suggesting rain even with
temperatures dipping into the 30s at night over the weekend.

Dry and warmer weather expected by the end of next week with upper
ridge building across the northern Rockies. Ebert


&&

.AVIATION...
FLIGHT CAT: VFR - MVFR.

SYNOPSIS: Isolated Rain showers are anticipated for the TAF sites
through today and tonight. Chances of showers persists through
the TAF period. Many of these chances are below 50% and will
likely be represented as VCSH in the TAF. These showers will bring
lowering ceilings with MVFR conditions possible.

WIND: N to NE at less than 10 kts this morning... increasing to
10 to 15 kts this afternoon... and then reduce back to less than
10 kts tonight.

GAH


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

weather.gov/glasgow



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