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000
FXUS65 KTFX 291651
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
950 AM MST Fri Nov 29 2013

.UPDATE...
Latest analysis shows a weak upper-level disturbance coming across
the Rocky Mtn Front this morning, bringing mostly cloudy skies and a
few mountain snow showers from around Lincoln north to Glacier NP.
Some of the clouds will continue downstream, resulting in partly
cloudy skies for portions of central MT, but expect all the
precipitation to remain along the Front. Another day of above-normal
temperatures, with highs from the mid-40s to low 50s across the
region. No significant forecast adjustments this morning, just a few
minor tweaks to temps and sky cover.  Waranauskas

&&

.DISCUSSION...
Today through Sunday...Northwest mid/upper flow pattern will
continue across the region into the early part of the weekend. A
couple of weak embedded shortwave troughs will move through the
area bringing the potential for mountain snow showers. Fast moving
nature of these shortwave troughs combined with limited moisture
will limit accumulation but could see a few inches at the highest
elevations. Plains will remain primarily dry but have maintained
slight chance POPs for a few areas this afternoon and again on
Saturday. Afternoon temps through Sunday will generally be 5 to 15
degrees above normal. Winds Sunday afternoon will begin to
increase across central/north-central Montana as the pressure
gradient tightens ahead of the more potent system set to impact
the region early next week. Foltz

Sunday Night through Saturday...Medium range forecast models are
slowing down the progression of the strong cold front expected to
move through the area. As a result, have warmed temperatures for
Sunday night into Monday. Lows Sunday night will be well above
normal with gusty westerly downslope winds and cloudiness. Have kept
the introduction of the cooler air along the Rocky Mountain Front on
Monday, but am not expecting the cold front to move through the
remainder of the area until the overnight hours across north central
Montana and through Tuesday in the southwest. On Tuesday,
temperatures should only be in the the single digits in the north
and lower teens in the south. The cold airmass will remain over the
area through the remainder of the week, keeping highs mostly in the
single digits above zero and lows in the single digits below zero.
The GFS is an outlying model that wants to moderate the cold airmass
briefly Wednesday into Thursday, so will hold off on this slight
warming for now. Breezy northerly winds behind the cold front will
also cause wind chill temperatures to fall into the 20 to 30 below
zero range beginning late Monday night and continuing into the day
on Wednesday. Therefore, wind chill highlights may be needed. If
skies become partly cloudy overnight at times, these lows could even
reach teens below zero after the winds decrease. Confidence
regarding much colder temperatures remains high, but the forecast
models continue to disagree on the exact placement of the heaviest
precipitation, so confidence regarding heavy snow across the entire
area remains low. Have therefore gone with fairly widespread light
snow for lower elevations for now for Monday through Tuesday.
Confidence remains high that mountain locations will likely see
heavy snow. Therefore, eventual winter weather highlights for the
mountains appear more likely. The chance for precipitation will
decrease after Tuesday as the feed of Pacific moisture gets cut off
by a deepening upper level trough over the western United States.
Coulston

&&

.AVIATION...
UPDATED 1200Z.
VFR conditions are expected to continue across the area through at
least 12Z Saturday. Two separate weak disturbances in the
west-northwest flow aloft will bring increasing mid level
cloudiness, possibly with a few showers and some mountain
obscuration, to the area. A weak cold front will also move southeast
across north central and central Montana, shifting gusty southwest
winds more west-northwesterly there for a while during the day.
Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  51  31  51  32 /   0  20  20  10
CTB  45  28  45  27 /   0  10  10  10
HLN  46  31  46  32 /   0  20  20  20
BZN  45  26  45  28 /   0  10  30  20
WEY  34  18  32  19 /   0  20  40  40
DLN  47  27  45  29 /   0  10  20  20
HVR  41  22  42  24 /   0  10  10  20
LWT  50  29  49  28 /   0  10  10  20

&&

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

$$


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