Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 240423
AFDGGW

Area Forecast Discussion
National Weather Service GLASGOW MT
923 PM MST Thu Feb 23 2017

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

AFTERNOON UPDATE:
Changes to the forecast were very minor this evening. High
pressure has moved through at the surface sitting just above this
thin surface layer is a blanket of stratiform super cool water
clouds. Over this is a are occasional mid-clouds with ice crystals
that seed the lower layer to generate isolated to scatter snow
showers. Most models have not caught onto this dynamic and 1 hour
pop fields are practically clear across the broad majority of
northeast montana when radar shows they really are not. Have
switched language in WX grids from probability to coverage to try
to help more accurately describe the phenomenon. PoPs themselves
are unchanged. Most other grids were not touched either. GAH


PREVIOUS SHORT TERM DISCUSSION:
A long-wave upper level trough occupies the western half of
CONUS. This trough has spread cooler air from the north over most
of the West, including Montana. The trough will eventually spread
across all of CONUS, keeping the cooler air in place for our
region. Expect only isolated-to- scattered light precipitation,
mostly snow through the short-term period.

Tonight Northeast Montana will reside under an amorphous flow
aloft and at the surface. The existence of general low pressure
and micro disturbances will tend to produce low stratus and
isolated light snow showers. Patches of Sun today and snow on the
ground, along with weak winds and temperatures near the dew
points could also generate patches of fog or mist.

Friday through Saturday conditions don`t change much, but
thickness heights slowly go lower. So, expect temperatures to
hover around normal or slightly cooler. Saturday afternoon a
short-wave disturbance rotating around the Hudson Bay low will
swing through Northeast Montana to increase the chance for
possibly measurable snow, up to an inch or so. Winds from the
north will add to the CAA.

Templer


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

No big changes to forecast grids today. Models are in agreement
with ridge returning to Montana late in the period, so
temperatures will begin to modify. TFJ

PREVIOUS LONG TERM DISCUSSION:
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...

MVFR/IFR into Friday morning, then improving to VFR.

Low clouds and light snow showers with patchy fog will continue to
affect the TAF sites into Friday morning. Ceilings should lift
Friday. TFJ/Proton


&&

.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.

Cool temperatures have slowed down melting.
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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