Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 021800
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1100 AM MST Mon Mar 2 2015

.UPDATE...Canadian cold front has pushed through KCTB and most of
the western portion of central Montana with snow gradually
developing from north to south. Unfortunately, the immediate
passage of the front has resulted in slightly rising temperatures
as the colder air remains a hundred or so miles behind the
boundary. As a result, expect another hour or so of warming before
temperatures begin to fall so have updated today`s Max temperatures
to avoid having highs lower than current observations. Have also
made some minor tweaks to winds and to PoPs in the southern half
of the forecast area. System continues to look on-track for
advisory level snow amounts with blowing snow and below zero wind
chills. mpj

&&

.AVIATION...
UPDATED 1800Z.
Cold front pushed through KGTF just before 17z Monday and will
continue to push south through central and southwest Montana this
afternoon. Start of snow 1 to 2 hours behind front. MVFR/IFR
expected as -SN...occasional SN...and gusty north winds causing BLSN
continue into overnight hours. Short periods of LIFR conditions are
possible with any bands of moderate snow and in vicinity of
mountains. As system continues push south and east...-SN will begin
to taper off and conditions improve vcnty KCTB/KHVR 02Z-06A and
through the evening/overnight hours at remaining local airfields.

&&

.PREV DISCUSSION...
/ISSUED 435 AM MST Mon Mar 2 2015/
Monday through Wednesday...The cold front is expected to move into
the area late this morning and continue to progress south across
most of Central Montana by the early afternoon. Strong winds, snow
along with a dramatic temperature drop can be expected behind the
front. Expected snow amounts are not changing dramatically at this
point, however with gusty winds accompanying the precipitation
accurate measurements of snowfall are going to be tricky. Near
whiteout conditions will be possible at times through the day Monday
and into Tuesday Morning. Temperatures are expected to fall below
zero with no significant rebound by Tuesday Morning. After the snow
ends on Tuesday another round of winter weather advisories may
become necessary due to the threat of low wind chill values. The
coldest temperatures may occur Wednesday morning before southwest
winds begin to develop and warm temperatures back toward the 20s and
30s.

Wednesday Night through Monday...Extended forecast period currently
looking mostly uneventful, with broad ridge of high pressure over
the western states and Pacific coast bringing dry conditions and
warming temperatures.  With the center of the ridge only moving from
the coast to the Great Basin area during this period, Montana will
be under persistent northwesterly flow aloft, with most of the
available moisture being deflected more into eastern parts of the
state.  Latest forecast models are in good agreement overall, with a
slight exception Fri aftn to midday Sat.  The GEM, GFS and ECMWF all
depict some variation of a shortwave trof crossing through the top
of the ridge at that time, but only the EC shows a more developed
low pressure system with widespread light snow occurring mainly Fri
night. Have kept a mention of scattered snow showers for the Rocky
Mtn Front and the central/southwest mtn ranges to cover the EC`s
solution but have little/no snow for the lower elevations.  May see
windy conditions as well for the central and Hiline counties on
Thurs and Sat as leeside surface trofs develop, creating favorable
pressure gradients for stronger winds.  Finally, after warming back
into the low-mid 40s on Thurs, temps don`t change much each day,
perhaps making it to the upper 40s to around 50 degrees for the
weekend.   Waranauskas

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  -4   7  -5 / 100  90  20   0
CTB  30  -6   5  -7 / 100  30  10   0
HLN  33   3  14   0 /  80 100  30   0
BZN  37   1  14  -4 /  20 100  40  10
WEY  34  -2  15 -20 /  20  70  40   0
DLN  38   1  17  -4 /  20 100  30  10
HVR  33  -4   5  -9 /  80  30  20   0
LWT  35  -5   5  -8 / 100  90  30  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 5 PM this afternoon to 11 AM MST
Tuesday Beaverhead...Broadwater...Gallatin...Jefferson...
Madison...Meagher.

WINTER WEATHER ADVISORY until 5 AM MST Tuesday Cascade...Central
and Southern Lewis and Clark...Chouteau...Eastern Teton...
Fergus...Judith Basin...Southern Rocky Mountain Front.

WINTER WEATHER ADVISORY until 5 AM MST Tuesday Eastern Glacier...
Eastern Pondera...Northern Rocky Mountain Front...Toole.

&&

$$

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