Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 190310 AAA

Area Forecast Discussion...UPDATED
National Weather Service Glasgow MT
810 PM MST Sat Nov 18 2017

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

Satellite imagery shows a shallow upper-level ridge moving east
across Montana. Yet the surface analysis places the stationary
boundary northwest to southeast across Northeast Montana. Moisture
aloft riding over the top of the ridge and along the stationary
boundary has found a focus for mostly high cloud development, and
broken skies tonight.

Low pressure over Hudson Bay will still influence our
temperatures. But, with increasing heights from the west, colder
temperature range across the northeast, then warmer in the
southwest. While temperatures reached normal today, these
increasing heights will drive Sunday highs 10-15 degrees above

Southwest wind is based on a broad surface low in the lee of the
Canadian Rockies and high pressure to our south. These mostly
light winds will amplify more after sunrise.


Previous discussion:
The short term is going to be dominated by high pressure. This
means conditions will be dry and skies will generally be mostly
clear to partly cloudy across the region. Some blustery winds on
the backside of the passing trough will diminish overnight, but
will return as southwest flow at the surface develops tomorrow
ahead of an approaching low pressure system expected on Monday.


.LONG TERM...Sun night through Sat...

Afternoon Update: The biggest story of the extended period remains
the cold front expected on Monday. Confidence is increasing that
this front will be strong enough and move through at the right
time to cause the daily high temperature to be relatively early in
the day, with falling temperatures through the afternoon and
overnight into Tuesday morning. Precipitation is still possible,
but is shifted a bit more towards the southwest. Winds seem to
remain strong enough overnight behind the front to warrant some
wind chill concerns early Tuesday morning in the northern zones.
Beyond that, the forecast still remains relatively intact from the
morning package.


PREVIOUS DISCUSSION: Surface low moves across Saskatchewan Sunday
Night as an upper trough moves through the Canadian Prairies
Sunday Night and Monday. Mild temperatures will continue to
prevail Sunday Night over the forecast area with warm air over the
area. However, a strong but mainly dry cold front drops southeast
across the forecast area Monday morning. The front will bring
gusty west to northwest winds which will likely be strong enough
for a Lake Wind Advisory for Fort Peck Lake. Cold air advection is
also expected to be strong enough for falling temperatures Monday

Much colder temperatures will prevail Monday Night as high
pressure builds into the area from Canada. The cold temperatures
will continue on Tuesday in NW flow aloft and the surface high
over the area.

Tuesday Night and Wednesday morning, flow aloft turns more WNW
and a warm front moves east across Eastern Montana. There may be
enough overrunning moisture for a slight chance of rain or snow
showers Wednesday morning in the east. Much warmer temperatures
move into the area on Wednesday with highs ranging from around 40
NE to near 60 SW.

Upper ridge moves through the area on Thursday which will allow
for a warm and dry Thanksgiving Day across the region.

A shortwave trough moves along the MT/Canada border Thursday Night
and Friday which will bring a cold front with somewhat cooler
temperatures on Friday. Another shortwave Friday Night will bring
another cold front through the area which will return temperatures
to near normal for Saturday. Forrester



Flight Category: VFR tonight and Sunday.

Synopsis: A high pressure ridge moves over the region tonight and
Sunday, spreading mid-to-high level clouds.

Wind: southwest 5-10kt tonight. Sunday, increasing to around
10-15 kts.





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