992 
FXUS65 KTFX 290500
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1000 PM MST Tue Nov 28 2017

...Updated Aviation Discussion...

.UPDATE...

Upper level trough continues to push east across WA/OR this 
evening with anticipated arrival into western MT around 06z 
tonight then continuing east across central and SW MT Wednesday 
morning. Little change from previous forecast with bulk of the 
precipitation expected to fall over the western and SW MT 
mountains tonight through tomorrow morning. Snow showers are also
possible across much of SW MT with the passage of the cold front 
later tonight and also across portions of north central MT 
Wednesday morning as a secondary piece of shortwave energy swings 
through, temporarily shifting mid-level for the northwest. 
Hoenisch

&&

.SYNOPSIS...

Weather system sweeps across the region tonight and Wednesday 
bringing snow to the western and southwest Montana mountains.
Scattered to numerous showers can be expected over the plains
Wednesday morning with only minor snow accumulations expected.
Breezy and seasonably cool conditions are expected Thursday and
Friday.

&&

.AVIATION...
Updated 0500Z. 

Increasing cloud-cover this evening ahead of an upper level trough 
and cold front approaching from the Pacific NW. Front crosses north 
central and SW MT overnight with a period of precipitation and 
terrain obscuration over the Mtns. A brief period of MVFR conditions 
is possible as this system moves across SW MT tonight accompanied by 
scattered snow showers. Winds shift from S/SW to more westerly 
behind the frontal passage tonight with breezy to locally windy 
conditions continuing on Wednesday as clouds decrease. CC/Hoenisch

&&

.PREV DISCUSSION...
/ISSUED 423 PM MST Tue Nov 28 2017/

Tonight through Thursday...Good agreement in short term models and
guidance so forecast confidence is fairly high. Upper level trough
currently along the West Coast moves eastward overnight with an
associated surface cold front moving east of the divide by
morning. This system is moderately moist but very quick moving so
am anticipating the greatest snow amounts will be confined to the
mountains along the Continental Divide, and especially near
Glacier National Park. Accumulation amounts through Marias Pass
are about 4 inches and areas of blowing snow are anticipated so
have issued a Winter Weather Advisory for elevations above 5000
feet along the Northern Rocky Mountain Front. Scattered to
numerous showers will also move out over the plains, mainly
between 6AM and 11AM MST Wednesday, but accumulations are expected
to be generally less than an inch. Skies are expected to clear out
across the entire forecast area Wednesday afternoon as the system
continues it's rapid eastward progression. Generally zonal flow
aloft develops over the region by Thursday so am anticipating
breezy conditions with variable clouds and seasonable temperatures
for Thursday. The only precipitation anticipated Wednesday night
and Thursday will be light high mountain snow near Glacier Park.
mpj

Thursday night through Monday...We return into a zonal upper-level 
flow pattern by late week with generally dry, cloudy and cool 
conditions likely. The next potential major storm system is due to 
arrive this upcoming weekend. At this time, large discrepancies 
exist in most long-range model guidance leading to a low-confidence 
weather forecast. However, the potential for widespread rain and/or 
snow, followed by much colder temperatures late weekend and into 
next week looks very possible and will continue to be closely 
monitored with more details as we get through the week ahead. KLG

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  38  42  29  44 /  10  20   0   0 
CTB  34  39  27  41 /  20  20   0   0 
HLN  31  40  22  40 /  20  20   0   0 
BZN  28  37  15  35 /  20  30   0   0 
WEY  19  30   9  29 /  60  50   0   0 
DLN  27  34  17  35 /  40  20   0   0 
HVR  37  46  24  44 /  20  70   0   0 
LWT  35  38  24  43 /  10  30   0   0 

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 8 AM MST Wednesday above 5000 feet 
for Northern Rocky Mountain Front.

&&

$$

http://www.weather.gov/greatfalls