Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 272344
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
443 PM MST Tue Jan 27 2015

.DISCUSSION...

Tonight through Thursday...Satellite imagery showing moisture
plume just getting into southwest Montana. Snow will develop over
the southwest but amounts do not look to be significant. Winter
Weather Desk analysis agrees with snow amounts of 1 to 2 inches in
the valleys with 3 to 5 inches in the mountains. The associated
shortwave moves rapidly across the area and this will also help
limit accumulation amounts. The snow gradually ends by afternoon
as high pressure begins to build back in over the area. Dry
conditions return on Thursday. Cooler air will move across the
area Wednesday as a weak Canadian cold front pushes through.
Temperatures, however, will remain above seasonal averages
Wednesday and Thursday.

Thursday night through Monday...Models are in agreement in
forecasting a return to colder and snowier conditions over the
weekend. The period will start off quiet with dry conditions and
relatively light downslope winds over the plains. A cold air mass
will spread southeast Friday night into Saturday and will be
accompanied by snow. The ECMWF model run is faster with the cold
air mass and snow than the GFS model run. Temperatures on the order
of 40 degrees in the early evening on Friday will fall to the
upper teens to lower 20s by early Saturday morning with
temperatures not recovering to freezing except over far southwest
Montana Saturday afternoon. Snow accumulations could range from 1
to 3 inches. Then another surge of cold air and snow will spread
south Sunday and Sunday night with the ECMWF model run again
faster than the GFS model run with the snow and cold. This latter
surge could bring an additional 1 to 3 inches of snow
accumulation. Note that timing of the snow and snow accumulations
will likely change over the course of the next few days. The
previous run of the GFS model started to moderate temperatures and
go drier early next week but the very latest run of the GFS is
more in line with the ECMWF which keeps most of the area in cold
air with periods of light snow. Blank

&&

.AVIATION...
UPDATED 2342Z.
A high pressure ridge over the western US is keeping most of Central
Montana warm and dry. A weak shortwave moving across Southwest
Montana will bring a chance of MVFR cigs south of a KDLN to KBZN
line during the night. Vsbys may also be reduced due to snow mainly
at higher elevations. A cold front will cross the Canadian border
early Wednesday morning and bring a chance of MVFR cigs across
Central Montana. Elsewhere VFR conditions will prevail through
Wednesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  38  47  29  44 /  10  10   0   0
CTB  36  46  26  44 /  10  10   0   0
HLN  31  46  24  41 /  20  10   0  10
BZN  29  44  23  40 /  50  30  10  10
WEY  31  38  20  34 /  80  50  10  10
DLN  34  49  27  44 /  40  20  10  10
HVR  33  43  25  41 /  10  10   0   0
LWT  34  40  23  42 /  10  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

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