Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 201716
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1015 AM MST Sat Jan 20 2018

Updated Aviation Discussion

.UPDATE...

No significant changes this morning. Recent satellite imagery
shows clear skies over much central Montana with some mid level
cloud-cover lingering over SW MT and mid to high level clouds
also along the Continental Divide to the north. Shortwave ridge
progresses east into western and central MT for generally dry
conditions except for some light snow showers in the Glacier Park
area near the divide. Additional drying aloft with the incoming
weak ridge should result in decreasing cloud-cover over SW MT
later today. After a cold start in SW MT, where fresh snowcover
exits, temperatures there may be slower to warm today while areas
to the north reach afternoon temperatures near climatological
averages. Hoenisch

&&

.SYNOPSIS...

High pressure over the Great Basin and a low pressure trough in
Alberta will combine for breezy to windy conditions over North
Central Montana through the weekend. Mostly dry conditions and
seasonable temperatures are expected at lower elevations. However,
the mountains near Glacier National Park will see periods of high
mountain snow today through Sunday.

&&

.AVIATION...
Updated 1715Z.

Upper level ridge moving across the Northern Rockies Today/Tonight
will maintain NW to W flow aloft with generally dry conditions. A
few snow showers and Mtn obscurations are possible along the
continental divide, otherwise VFR conditions will prevail at area
terminals. Some moisture entrained within flow aloft will bring
varying amounts of mid to high level cloud-cover with breezy SW wind
continuing on the plains. Hoenisch

&&

.PREV DISCUSSION...
/ISSUED 431 AM MST Sat Jan 20 2018/

Today through Monday...Montana will remain beneath a shortwave
ridge aloft this weekend while energy associated with a broad
upper trough moves through the southwestern USA. Downslope
pressure gradients along the Rocky Mountain Front will cause
breezy to windy conditions to prevail across North Central
Montana and temperatures will remain near seasonable averages.
Additionally, mostly dry conditions will prevail at lower
elevations through the weekend. The only exception to this will be
the higher mountains in and around Glacier National Park where
periods of snow can be anticipated today through Sunday.
Conditions are expected to change Sunday night into Monday as a
progressive westerly flow aloft brings shortwave energy through
the region. Widespread mountain snows will develop along the
Continental Divide and there will be an increasing chance for
precipitation for much of Southwest Montana. At this time, it
appears that snow amounts will remain generally light and I do not
anticipate the need for any winter weather highlights. mpj

Monday night through Saturday...Shortwave energy moves east of the
forecast area Monday night into Tuesday with precipitation
decreasing over the region. Medium range models are in good
agreement that a progressive flow aloft will move a broad upper
level ridge over the state Tuesday evening through Wednesday
morning for mostly dry conditions at lower elevations and slightly
warmer temperatures. However, the prevailing westerly flow aloft
will continue to bring a chance for light mountain snows along the
Continental Divide. By Wednesday evening a broad upper level
trough moves inland across the western USA, with the bulk of
associated energy and precipitation remaining mainly south of
Montana. Despite this, Montana is still expected to see a general
cool down in temperatures with unsettled conditions associated
with the upper trough bringing a chance for snow showers off and
on from Wednesday night through Saturday. mpj

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  38  24  34  25 /   0  10   0  10
CTB  37  20  34  22 /  10  10   0  20
HLN  30  12  27  13 /   0  10   0  20
BZN  23   6  24   4 /   0  10  10  20
WEY  23  -5  22   7 /  10   0   0  30
DLN  25  12  26  15 /   0  10   0  30
HVR  32  17  27  13 /   0  10   0  10
LWT  34  18  32  18 /   0  10   0   0

&&

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

$$

http://www.weather.gov/greatfalls


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