Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 231606
AFDGGW

Area Forecast Discussion
National Weather Service GLASGOW MT
906 AM MST Thu Feb 23 2017

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

Radar imagery this morning is showing snow showers mostly along
and north of the Hi-Line. Also all airport observation sites are
showing visibility reduced by fog/mist (BR) and light snow. This
is generally well covered by the ongoing forecast. However did add
fog to the southeast where it has also developed.

Templer

Previous discussion -
Synoptic Setup: short term begins with northeast Montana sitting
under zonal flow and embedded firmly within a pacific Airmass. To
the west this airmass expands out over the Pacific Northwest and
off the coast in a large trough. To the north the airmass gains a
more arctic value to it over central Alberta and Saskatchewan.
The PACNW trough connects to this arctic airmass over central
Albert a through southern British Columbia.

Today thought Saturday: Zonal flow maintains over the next 48
hours with small meso-scale perturbations in the flow and weak
frontal boundaries drifting across the area that become the focus
for isolated to scattered snow showers. Each model is playing
large county wide differences in placement of these narrow zones
as well as timing differences of nearly 6 hours when stronger
features do show up. Because of this confidence in any particular
12 hour period being impacted by snow is low. However, Friday
through Friday night do appear to have a higher chance as the
front of the incoming trough should provide larger baroclinic
zones to form with weak lift and subsequent snow showers. GAH


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

Upper trof will dominate over North America through most of next
week. Several shortwaves are expected to move through the
northwest flow across the region producing occasional light snow
but no major event is anticipated. Overall temperatures will
return to near normal values for late February. Ebert

&&

.AVIATION...

Patchy fog and light snow will lift a bit today with MVFR
conditions becoming VFR from north to south.

Lowering ceilings return later tonight into Friday. TFJ

&&

.HYDROLOGY...

Ice jams and high water levels continue at some of the sites.

The Milk River in Valley County stream levels have generally
stabilized. However, a flood watch continues mainly for the Milk
River, although the reading this morning at Glasgow brought the
river below action stage. The reading at Nashua has also stabilized
below action stage.

Ice break-up and ice jams are causing water levels to fluctuate
on the Yellowstone River near Glendive and further downstream,
although a report this morning had the Yellowstone wide open at
Sidney. No flooding of concern has been reported. The Flood Watch
remains in effect for Dawson and Richland counties.

The water level on the Big Muddy River near Antelope crested at
11.35 feet or 0.65 feet below flood stage and is now slowly
falling. Plugged culverts in the area appear to have been
cleared. A Flood Watch remains in effect here.

Some county controlled low water crossings over the area do have
water running across them.

The Frenchman Creek in northeast Phillips county seems to have
crested at 13.45 feet or 1.45 feet above flood stage and is now
falling. A Flood Warning is in effect for this creek system.
BMickelson/sct


&&

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

&&

$$

weather.gov/glasgow


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