Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 212203
AFDGGW

Area Forecast Discussion
National Weather Service GLASGOW MT
303 PM MST Tue Feb 21 2017

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

Surface pressure gradients are tightening up across eastern
Montana this afternoon as low pressure has developed north of
Billings. High pressure over Alberta continues to nose south. A
polar front this afternoon over southern Sask is drifting south.

Conditions will return to a winter feel for many tonight as the
low moves east through the Dakotas and more cold air spills in
from Canada. Sub-freezing temperatures at around 850 mb should
support precipitation changing over to snow first over the
northern zones. Precipitation should not be heavy enough through
Wednesday for an accumulation except in SW Phillips county where
several inches are expected from tonight through Wednesday Night.
The Winter Storm Watch has been downgraded to an Advisory here.

The cloudy and cool conditions Wednesday continue into Thursday as
an upper trough moves in from the Gulf of Alaska. The coldest air
stays to our northeast but temperatures will be cooler and close
to normal the next couple of days. TFJ

.LONG TERM...Thu night through Tue...
The main story will the a broad upper trough with disturbances
that will bring cooler conditions and period of snow showers. Main
grid edits were to only refresh with the latest guidance through
Saturday, except went all the way out for temperatures. Highs and
lows can be expected to be more seasonal than of late.

Templer

Previous discussion -
The long range period begins Thursday night into Friday with
departing storm system. However, a broad upper level trough will
remain centered across the region for much of the second half of
the week. This will maintain relatively cold temperatures and at
least some chances for light snow due to the upper level forcing
for ascent.

Current 00z model runs show that the trough eventually pushes out
of the area while an upper level ridge develops over the northern
Rockies. Expect drier weather conditions to result though 500mb
heights still low enough to drive high temperatures mainly below
freezing. Maliawco


&&

.AVIATION...

An upper-level trough off the Pacific Coast is sending moisture
into the Pacific Northwest, including Northeast Montana. A
frontal boundary has initiated rain showers. Cooling temperatures
tonight will transition rain to snow through Wednesday morning.

Expect lowering ceilings late today or this evening as rain
moves northeast. Reduced visibility in precipitation as well as
lowering stratus may result in MVFR and IFR conditions tonight.

Winds: Light west to southwest today at 5 to 10 kts, becoming
northerly tonight, possibly increasing to around 15kt by morning
in the east.

Templer


&&

.HYDROLOGY...

Ice jams continue at some of the sites this afternoon.

The Milk River near Glasgow continues to rise today, but still a
ways from flooding, so the Flood Watch seems appropriate here.

THe Yellowstone River near Glendive is steady or slowly falling.
The Flood Watch remains in effect for Dawson and Richland
counties.

The level on the Big Muddy River is leveling off near Antelope.
Plugged culverts in the area appear to have been cleared. A Flood
Watch remains in effect here.

The Frenchman River in northeast Phillips county continues to
rise. A Flood warning is in effect here. TFJ

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from midnight tonight to midnight MST
Wednesday night for Southwest Phillips.

Flood Watch through Wednesday afternoon for Central and Southern
Valley...Dawson...Richland...Sheridan.

&&

$$

weather.gov/glasgow


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