FXUS65 KTFX 111810 AAA

Area Forecast Discussion...UPDATED
National Weather Service Great Falls MT
1110 AM MST Mon Dec 11 2023

Aviation Section Updated


A weak cold front moves south across the region today with areas
of snow affecting primarily north-central and central Montana
this morning. Drier conditions are expected Tuesday and Wednesday,
but breezy to windy southwesterly winds return.



As of 8 AM, radar imagery and surface observations show light
rain and snow across Central Montana moving southward into
Southwest Montana this morning. Rain/Snow should arrive in
locations from Helena to White Sulfur Springs within the next hour
as the cold front moves southward across our CWA this morning.
Please use caution while driving this morning as roadways could be
icy and/or slippery in locations that see precipitation and below
freezing surface temperatures as well as periods of reduced
visibility below 6 miles with falling snow. As the cold front
continues to move southward, precipitation should be ending by
late this morning and this afternoon from north to south across
Central and Southwest Montana. Fog has been periodically observed
on webcams and night fog satellite across Bozeman and Belgrade
this morning.

The Winter Weather Advisory for the Little Belt and Highwood
Mountains continues through 1 PM and was expanded to include the
Southern Rocky Mountain Front as snowfall can accumulate to
between 1 and 3 inches and winter weather impacts continues
through the morning hours such as slippery roadways and reduced
visibility with falling snow. Webb


1100 AM MST Mon Dec 11 2023 (11/18Z TAF Period)

From KGTF to KLWT, we have a band of light to moderate snowfall that
will continue through 20z and 21z bringing LIFR to IFR conditions.
Mountain obstruction continues for Central Montana mountains until
this evening. For KHLN, a mix of rain and snow can be observed
through at least 21z. VFR conditions for KHVR and KCTB continue
through the TAF period. Visibility will improve to VFR conditions
later this afternoon for Central Montana airfields. For KBZN and
KEKS, there is potential in the morning hours for low level clouds
and fog to develop. The chances for fog were too low to include in
the TAFs at this time, but the potential for low clouds tomorrow
morning is high to be included in the TAF. Webb

Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.


/ISSUED 354 AM MST Mon Dec 11 2023/

A weak cold front was moving south across north-central MT early
this morning, roughly from Choteau to Chester at 3am where winds
have shifted to the NW with some slight cooling. Radar across north-
central MT and upstream across southern AB shows mainly light
returns but increasing coverage behind the front early this morning.
Hi-resolution models seem to have a good handle on the frontal
position and upstream precipitation and expect the development of
areas of light snow or flurries across much of north-central MT
by 5am with a more concentrated area of light snow likely to
develop from the Rocky Mtn Front southeast across the northern
portions of the Big Belt and Little Belt mountains and roughly as
far north as areas from Choteau to Great Falls and Stanford. The
frontal boundary and areas of light snow will continue south
through this afternoon with coverage decreasing as the front
weakens while moving through SW MT. Snow amounts have changed
little from previous forecasts with north-central and central MT
mountains ranges likely to see around 1-3" of snow while adjacent
valleys and plains can expect Trace to 1" amounts while little or
no snow accumulation is expected in the valleys of SW MT.
Precipitation ends form N to S this afternoon with some low clouds
lingering across central MT into early this evening before all
areas see skies clear tonight.

A dry and relatively mild stretch of weather begins Tuesday as
upper level ridging becomes established across the western US and
is likely to persist through the upcoming weekend. There is some
potential for windy periods across north-central MT as shortwave
disturbances move over the ridge across western Canada around the
middle of this week and again this weekend. Temperatures look to
fluctuate 10-15 degrees above seasonal averages for mid-December.
In fact, today's seasonably cool conditions may be the coldest of
the next two weeks with global model ensembles strongly favoring
an extended period of mild zonal from from the Pacific across the
continent through late December. Hoenisch


GTF  37  23  41  27 /  90   0   0   0
CTB  33  17  38  22 /  60   0   0   0
HLN  39  23  41  19 /  80   0   0   0
BZN  39  19  37  12 /  40  20   0   0
WYS  31   8  33  -1 /  20  10   0   0
DLN  37  20  35  14 /  10  10   0   0
HVR  36  15  37  20 /  50   0   0   0
LWT  36  20  41  22 /  70   0   0   0


Winter Weather Advisory until 11 AM MST this morning for East
Glacier Park Region.

Winter Weather Advisory until 1 PM MST this afternoon for Little
Belt and Highwood Mountains-Southern Rocky Mountain Front.