Area Forecast Discussion
Issued by NWS Glasgow, MT

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247
FXUS65 KGGW 202202
AFDGGW

Area Forecast Discussion
National Weather Service GLASGOW MT
302 PM MST Mon Feb 20 2017

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

A short-wave ridge of high pressure now prevails across the region
bringing mostly sunny skies, warmer temperatures, and light winds
to northeast Montana.

Next chance of rain showers will move into our western CWA tonight
with a subtle short-wave disturbance. Should be only light
accumulations if any at all, primarily north of the Missouri
River.

By Tuesday night, the flow aloft turns more from the SW and begins
to pull down colder air from Canada. As the latest model consensus
shows, a rain/snow mix seems likely Tuesday night through
Wednesday morning with an inch or less of accumulation possible.

Some left over lingering precip on Wed is expected to change back
over to rain for the last day above freezing before northeast
Montana is thrown back into another cold spell to round out the
week with additional snow accumulations possible.

BMickelson


.LONG TERM...Wed night through Mon...
With the main surface low still expected to move across Colorado
and Kansas Wednesday night through Thursday, much of the
precipitation is still anticipated to remain south of our area.
Temperatures will likely be warm enough for precipitation from
the northern stream Wed night-Thursday to start as rain or a
rain- snow mix before transitioning to entirely snow throughout
the area Thursday.

There is model disagreement beyond this point, but a chance still
exists of a weak shortwave to move through the area Friday, which
could bring a chance of snow to portions of the area.

Models are hinting at another weak shortwave potentially moving
through the area by the end of the weekend, bringing a slight
chance of snow to the area. This is too weak of a signal to have
any real confidence in, however.

Hickford
Previous Discussion...

Upper trough moves through the Central and Northern Rockies
Wednesday Night and Thursday. The surface low tracks well to the
south across Colorado and Kansas which will keep most of the
precipitation to the south of the forecast area with this system.
However, flow aloft becomes split with this system Wednesday Night
and models bring a northern stream wave across the region
Wednesday Night and Thursday that could bring a chance of snow
into Northeast Montana.

A weak wave on Friday could bring a slight chance of snow to the
southwest half of the forecast area.

NW flow aloft will prevail over the weekend and early next week
keeping temperatures near normal or slight below. Shortwave trough
on Saturday and again Sunday Night and Monday could bring slight
chances for snow into the area.

Forrester



&&

.AVIATION...

Flight Category: VFR conditions through tonight with mainly mid-
level clouds expected to move into the area. VFR and MVFR
conditions are expected Tuesday morning, with low and mid-level
clouds over the TAF sites.

Synopsis: A weak frontal system will move through the area late
tonight and Tuesday morning with some low clouds possible. Rain
chances return to the area Tuesday afternoon.

Winds: Mainly southwest winds at 5 to 10 knots tonight, becoming
westerly at 10 to 15 knots Tuesday.



&&

.HYDROLOGY...

Ice Jam was detected just south of Glendive on the Yellowstone
river Sunday afternoon and remains in place today. River levels
measured at Glendive show a steady, however slow, uptick in river
levels as the 6-mile long ice jam moves downstream into Glendive.
The river is still around 5 feet below flood stage this afternoon.

An ice jam at the Highway 24 bridge over the Milk River
downstream of Glasgow continues to remain in place today with the
water flowing through the ice for now. The Milk River is holding
steady around 21.7 feet or around 3.3 feet below flood stage. The
Milk River is beginning to crest in the Nashua area around 15.7
feet and is about 4 feet below flood stage today.

The Big Muddy river in Sheridan County near Antelope appears to
have crested today around 10.6 feet, which is around 1.4 feet
below flood stage.

The Frenchman Creek near the Canadian border in northern Phillips
County continues to hover around 11.5 feet today, or around a
half inch below flood stage.

The Beaver Creek near Saco (Guston Coulee) seems to have crested
around 10.3 feet today, or around three-quarters of a foot below
flood stage.

Continued warmer temperatures over the next few days will melt
more snow and break up more ice, keeping ice jam concerns
elevated through most of this week.

A flood watch continues for Prairie, Dawson, and Richland
Counties along the Yellowstone River for ice jam flooding through
Tuesday afternoon.

A flood watch continues for Sheridan County for the Big Muddy
River through Tuesday afternoon.

A flood watch continues for Valley County for areas along the
Milk River downstream of Hinsdale to the confluence with the
Missouri River through Tuesday afternoon.


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Tuesday afternoon for Central and Southern
Valley...Dawson...Prairie...Richland...Sheridan.

&&

$$

weather.gov/glasgow



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