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000
FXUS65 KTFX 050459
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
959 PM MST Wed Dec 4 2013

.UPDATE...

Extended the Wind Chill Advisory for areas along the Hi-Line and
eastern portions of the forecast area. Wind chills of -20 to -35
are expected with wind speeds at or greater than 10 mph. Also
lowered cloud cover and min temps from Great Falls to Cut Bank and
Havre based on current observations. Winds have decreased over
southwest Montana and along the Rocky Mountain Front, thus have
expired the Wind Chill Advisory for these areas. Even though no
accumulating snow or measurable precipitation is expected tonight,
there may be a few flurries. The remainder of the forecast is on
track so made no further changes. MLV

&&

.AVIATION...
UPDATED 0459Z.
A broad upper level low pressure trof will remain across Montana and
cold air will bring very cold temperatures to the region. VFR
conditions will generally prevail through the next 24 hours.
However, very cold temperatures and low level moisture could cause
local freezing fog and restricted visibilities in low lying areas.

&&

.PREV DISCUSSION...
/ISSUED 358 PM MST Wed Dec 4 2013/
Today through Friday...Moisture continues to move out of the
region today as the previous system exits the region. Breezy
northerly surface winds across North-Central Montana with single
digit temperatures are causing quite cold wind chills of 20 below
to 30 below zero at times. The Wind Chill Advisory for portions of
the area continue as a result. Winds should decrease over the
region overnight and wind chill will thus be less of a factor as
the night goes on. A secondary weak shortwave will come down out
of Canada Friday but any precipitation will likely be only over the
Southwest Montana Mountains. Expect very cold temperatures to
continue both during the day and at night with overnight lows
dropping below -20 degrees in many locations.

Friday Night through Wednesday...Cold temperatures will persist
into the early part of the coming weekend as a deep upper level
trough remains over the western USA. Latest medium range model
runs are in good agreement that a reinforcing shot of cold air
will push into Montana during the weekend so have kept the going
forecast for this period relatively unchanged. However, these
models are now coming into better agreement that the upper trough
will shift eastward Monday through Wednesday with westerly winds
developing across the region. This scenario suggests that
temperatures should begin to warm early next week. I have trended
a bit warmer than the previous forecast package but have not gone
as warm as guidance in case later model runs return to a colder
solution. mpj

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF -20   1 -19  -7 /   0  10  10  20
CTB -24  -3 -24  -8 /   0  10  10  20
HLN -13   4 -14  -3 /   0  10  10  20
BZN -16   4 -14   1 /  10  10  10  20
WEY -22   3 -15   9 /  10  10  20  40
DLN -12   7  -5   6 /   0  10  20  30
HVR -25  -5 -26  -8 /  10  10  10  10
LWT -18  -2 -22  -6 /  10  10  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until 11 AM MST Thursday Blaine...Chouteau...
Eastern Glacier...Eastern Pondera...Fergus...Hill...Judith
Basin...Liberty...Toole.

&&

$$


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