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000
FXUS65 KTFX 311754
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1055 AM MST Sat Jan 31 2015

.UPDATE...

Cold front has passed completely through North-central Montana,
with light to locally moderate snowfall developing behind the
front. North winds up to around 25 mph are helping a broad area of
upslope snow develop across Teton, Cascade, Chouteau, and Hill
counties. Snow is expected to continue in these areas through mid
afternoon before tapering. Snowfall rates have already slowed
along western portions of the Hi-line as temperatures turn colder.
Areas of blowing snow and snow covered roadways will slow travel
through the afternoon. Fair weather continues in southwest
Montana. Updated the forecast to strengthen winds per observations
across North-central Montana and raised QPF/snow slightly to the
west in Cascade and Teton counties. Overall forecast package with
Winter Weather Advisory remain in generally good shape. Nutter

&&

.AVIATION...
UPDATED 1755Z.
This is a low confidence forecast as guidance indicates conditions
ranging from VFR to IFR into Sunday morning. The period starts off
with widespread MVFR/IFR ceilings and visibilities in snow over the
plains with mountains generally obscured. Snow will diminish late
this afternoon and evening with visibilities generally improving.
The big forecast problem is what will happen overnight as some
guidance develops VFR conditions while other guidance lowers
ceilings to IFR and also develops IFR visibilities in freezing fog.
Do not have a strong feeling as to which way to go. For southwest
Montana for early this afternoon expect conditions to range from VFR
over Beaverhead County to periods of MVFR/IFR ceilings and
visibilities and mountain obscurement in snow for northern portions
of southwest Montana. Here snow will diminish later this afternoon
and early evening with conditions becoming generally VFR. Like with
the plains conditions Sunday morning could range anywhere from VFR
to IFR in freezing fog. Blank

&&

.PREV DISCUSSION...
/ISSUED 441 AM MST Sat Jan 31 2015/
Today through Monday...A Canadian cold front continues to push
southward through the region. As of 3 AM...the cold front was
along a line from just south of Great Falls to just north of
Lewistown. The cold front will continue to move southward through
the day...and should be in the Helena area by mid morning...and in
the Bozeman area around mid day. The cold front will likely slowly
back into the Dillon area by late afternoon. Temperatures will
slowly fall behind the cold front...thus morning high temperatures
expected in many areas. Light snow is slow to develop over North
Central MT...but as of 3 AM...it is slowly developing north of
Highway 2. The previous forecast for snowfall looks on track. I
did add Judith Basin to the advisory...as some blowing snow will
affect that region as well. Most of the accumulating snowfall will
end this evening...so I did end the advisory at Midnight tonight.
For Sunday...the cold air will start to retreat a bit...especially
for areas west of I-15 and south of Great Falls.
Additionally...precipitation will develop during the afternoon
hours mainly west of I-15...and spread eastward overnight.
Temperatures will be near freezing...so some rain will mix in. At
this time...I held off on freezing rain and will monitor that
closely. For Monday...snow is likely to continue up in the Havre
area...as the warm front stalls out in that region. Scattered
rain/snow showers will be possible elsewhere. Snowfall amounts on
Monday will generally be in the 2 to 3 inch range over the western
mountains and in the Havre area...with lesser snowfall amounts
elsewhere. Brusda

Monday night through Saturday...Models remain in good agreement
bringing another batch of cold Canadian air southward with snow
developing behind the front. This system will continue to move
southward through the state with precipitation moving into southwest
Montana Tuesday night. For the remainder of the period, models
continue to be somewhat in agreement attempting to build an upper
level ridge over the region. However, tonights model runs suggest
that multiple shortwaves in the flow aloft will suppress ridge
development and bring a few periods of showers to the state.
Temperatures will likely warm back toward seasonal averages by
Thursday with highs expected to climb above average Friday and
Saturday. Breezy to windy conditions will prevail over the plains
and there appears to be a good chance the high winds will affect the
Rocky Mountain Front at times from Thursday night through Saturday.
mpj

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  30   9  34  30 / 100  30  20  30
CTB  25   5  28  20 / 100  20  20  30
HLN  33  11  34  28 /  30  10  10  20
BZN  36  12  32  26 /  10  10  10  30
WEY  27   8  28  22 /  10  10  20  40
DLN  31  18  38  28 /  10   0  10  30
HVR  25   4  25  19 / 100  40  10  30
LWT  25   6  30  25 / 100  40  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 11 PM MST this evening Cascade...
Fergus...Judith Basin.

WINTER WEATHER ADVISORY until 11 PM MST this evening Blaine...
Chouteau...Hill.

&&

$$

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