High Wind in Montana, December 26 to 27, 2019

Area Forecast Discussion
National Weather Service Great Falls MT
856 PM MST Thu Dec 26 2019

.SYNOPSIS...

Fair conditions with near normal temperatures will continue
through tonight. Breezy winds with mostly mountain snow showers
are then possible for Friday and Saturday. More light snow can be
expected Sunday into Monday, with a more widespread snowfall
possible by the middle of next week.

&&

.UPDATE...

Another relatively quiet evening across central and southwest
Montana. No major weather systems are expected in the next 24
hours, but some minor updates were required to the afternoon
forecast package. Biggest change was to add areas of dense fog in
some of the southwest valleys, but coverage is limited so do not
believe any dense fog highlights will be needed. Have also
increased wind speed and wind gusts, especially along the Rocky
Mountain Front, but they will stay well below high wind warning
criteria. Finally, with clear skies and a relatively dry airmass
in place, have lowered overnight minimum temperatures in some
areas. The coldest portions of the Great Falls CWA will be in the
valleys of southwest Montana and along the Canadian border. The
remainder of the forecast appears to be in fairly good shape so no
other changes are anticipated through the evening hours. mpj

&&

.AVIATION...
Updated 2325Z

Shortwave ridging aloft will keep skies mostly clear across a
majority of the Great Falls forecast area overnight through early
afternoon on Friday. Exception remains the KWYS terminal where low
clouds and fog are expected to persist through the forecast period.
Mid and lower level clouds west of the Continental Divide will also
cause mountain obscurations along the divide from the Canadian
border southward to the latitude roughly matching Augusta. Expect
increasing mid level clouds across the western half of the Great
Falls forecast area after 18Z Friday. mpj

&&

.PREV DISCUSSION...
/ISSUED 425 PM MST Thu Dec 26 2019/

Remainder of this afternoon through Sunday night...Generally fair
weather is expected through tonight as the flow aloft becomes
more zonal. West to southwesterly winds will increase along the
Rocky Mountain Front as the next shortwave approaches the region
form the northwest. This feature crosses the region within a
northwest flow aloft Friday into early Saturday and will produce
some periods of light, mainly mountain snow. After a brief break
Saturday night, more light snow returns on Sunday. Mountain areas
will be the primary recipient of this snow but lower elevations
may see a light dusting as well, mostly for locations southwest of
a Cut Bank to Lewistown line. Only minimal impacts are expected
from any snowfall this weekend. Temperatures will remain near
seasonal averages for North-central Montana, but colder air will
remain trapped in the colder southwest valleys, where overnight
lows will dip into the single digits above and below zero.

Monday through next Thursday...Drier conditions are expected to
move in by Monday afternoon, but it will be short lived as a
stronger system arrives some time Tuesday into Wednesday. This
will initially bring bringing a possibility for strong winds along
the Rocky Mountain Front and the north-central plains. Then a
more widespread precipitation event may follow, which may include
a potential for accumulating snow. There are some uncertainties
that need to be sorted out for this period but an overall turn to
unsettled weather is likely.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  37  21  34 /   0  10  10   0
CTB  18  34  17  32 /   0   0   0   0
HLN  12  31  17  31 /   0  10  10   0
BZN   9  30  12  29 /  10  10  20   0
WYS  -3  19  -1  18 /  20  20  20   0
DLN  -2  24   7  25 /   0  10  10   0
HVR  15  35  17  31 /   0   0  10   0
LWT  14  35  20  29 /   0  10  20  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

http://www.weather.gov/greatfalls