Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 242155
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
255 PM MST Mon Nov 24 2014

.DISCUSSION...
Tonight through Wednesday night...A northwest flow aloft will
occur during the period. A weather disturbance will move into
eastern Montana Tuesday morning. Moisture will increase ahead of
it and snow over the Rocky Mountain Front this evening will spread
to southwest Montana after midnight. Meanwhile at least scattered
snow will develop over the eastern plains. Then Tuesday afternoon
a band of lift and a very moist air mass will develop from the
Rocky Mountain Front into southwest Montana. For lower elevations
in southwest Montana expect a mix of rain and snow during the day
Tuesday. This band of lift and a very moist air mass will spread
northeast Tuesday night and into early Wednesday. Meanwhile some
drying will develop over southwest Montana late Tuesday night then
spread to North Central Montana by late Wednesday night as a
Pacific upper ridge moves east. A cooler air mass will move into
the north Tuesday but there is some question just how cool it will
be. The cooler air mass will continue over the north into
Wednesday. Meanwhile southwest Montana will be in the warmer air
with highs in the mid 30s to mid 40s each day.

As for the high wind warning for tonight into Tuesday morning
will continue it and winds were picking up in the warning area
Monday afternoon. As for the winter weather highlights will go
with a winter storm warming from the Rocky Mountain Front into
central Montana for later tonight into Wednesday evening. The
Rocky Mountain Front will see the heaviest snow. For other areas
in the warning heavy snow should be confined mainly to the
mountains. Elsewhere will have a winter weather advisory for
tonight into Wednesday evening. Note that snow will likely be
diminishing over southwest Montana by late Tuesday night and that
snow will not become widespread over north central Montana until
Tuesday night. Blank

Wednesday night through Monday...Model guidance continues to come
towards a consensus on the weather pattern for the bulk of the
long term. Temperatures are expected to be near seasonal values
for into Friday as a weak ridge moves into the area behind an
exiting winter weather system. Another round of moisture appears
to be be on the way by Friday evening with the next surge of cold
air moving South along the Rocky Mountain Front. Widespread
snowfall looks to begin Friday evening, lasting into Sunday in
some locations. Temperatures look to drop dramatically with this
cold air intrusion and highs may be limited to the teens and
single digits across much of Central and North Central Montana.
The coldest day appears to be Saturday. Temperatures slowly warm
up by the start of next week but Monday high temperatures may
still be at or below freezing for most of the area.

&&

.AVIATION...
UPDATED 1740Z.
The main message to get across is there will be deteriorating
conditions as moisture increases over the area. For the mountains
there will be widespread obscurement over the Rocky Mountain Front
by late afternoon which will spread to southwest Montana after
midnight. Otherwise ceilings should be above 15000 feet by late
afternoon and ceilings will lower overnight as at least scattered
snow develops for the lower elevations. The problem is how low
ceilings and visibilities will go. Expect some areas of MVFR or even
IFR conditions for the lower elevations to develop and these
conditions could become widespread by early Tuesday morning. Have
fair confidence in forecast winds into the evening but have low
confidence on wind direction and speed after midnight and into
Tuesday morning. Also note that there will be wind gusts to 50 knots

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  30  40  24  39 /  30  50  90 100
CTB  30  38  23  32 /  20  20  90 100
HLN  31  40  30  46 /  40  70  90  40
BZN  22  37  26  43 /  50  80  80  40
WEY  16  32  25  35 /  80  80  80  40
DLN  23  40  33  45 /  20  50  40  30
HVR  28  38  20  30 /  30  20  60  90
LWT  27  37  22  35 /  40  50  80 100

&&

.TFX WATCHES/WARNINGS/ADVISORIES...

HIGH WIND WARNING from 9 PM this evening to 1 PM MST Tuesday
Central and Southern Lewis and Clark...Northern Rocky Mountain
Front...Southern Rocky Mountain Front.

WINTER WEATHER ADVISORY from 11 PM this evening to 11 PM MST
Tuesday Beaverhead...Jefferson...Madison.

WINTER STORM WARNING from 11 PM this evening to 11 PM MST
Wednesday Broadwater...Cascade...Central and Southern Lewis and
Clark...Eastern Glacier...Fergus...Gallatin...Judith Basin...
Meagher...Northern Rocky Mountain Front...Southern Rocky
Mountain Front.

WINTER WEATHER ADVISORY from 11 PM this evening to 11 PM MST
Wednesday Blaine...Chouteau...Eastern Pondera...Eastern Teton...
Hill...Liberty...Toole.

&&

$$

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