Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 271730
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1030 AM MST Thu Nov 27 2014

...UPDATE TO AVIATION...

.UPDATE...

Observations reveal the threat for freezing rain has ended over
Hill and Blaine counties, so the Freezing Rain Advisory was
cancelled. Attention turned to observed winds along the Rocky
Mountain Front, and elsewhere around the region. Norris Hill in
Madison County and other locations adjacent to the Rocky Mountain
front report wind gusts over 50 mph this morning. Short term model
guidance, in particular the HRRR, combined with observed pressure
falls over the region provide adequate confidence to expand the
high wind warning to include Lewis and Clark and Cascade counties
along with Norris Hill. High winds will not occur everywhere in
these counties, but more likely at a few specific locations. Other
areas to watch closely include eastern Glacier county and adjacent
to the Sweet Grass Hills. Winds speeds are likely to decline below
warning criteria overnight, but could increase again Friday ahead
of the advancing Arctic Front. High temperatures in the lower 50s
today appears on track once winds mix down the 10C inversion
measured on the 12Z GTF sounding. Nutter

&&

.AVIATION...
UPDATED 1730Z.
A surface warm front will continue to move northeast through central
Montana this afternoon. Gusty southwest to westerly winds will
spread across the forecast area behind the front with very strong
winds possible along the Rocky Mountain Front and in other favored
locations. Mostly clear to partly cloudy skies today will give way
to increasing mid and high level clouds after 06Z Friday but VFR
conditions will prevail at all terminals. Looking ahead, a strong
Arctic cold front with widespread snow is expected Friday night and
Saturday. mpj

&&

.PREV DISCUSSION...
/ISSUED 445 AM MST Thu Nov 27 2014/

Today through Saturday....Very strong west flow ahead of an upper
level low pressure trof is moving across Central Montana. Winds
aloft will continue to strengthen this afternoon and evening. The
high wind warning for the Rockies will continue. Will not issue for
Eastern Glacier county although some concern here as well,
especially to the west near the slopes of the Rockies. However,
mixing level should remain quite low and do not expect upper levels
to mix down. But not real confident and quite possible for some
gusts to occur. Radar indicates light precip east. Forecast
soundings still show a warm layer at lower levels and will generally
include mention of freezing rain over the eastern zones where POPs
are above slight chance. A cold front will move from Canada across
the border late afternoon and move south through the zones during
the evening. Current timing shows low-level moisture crossing the
Canadian border as early as 2 in the afternoon, into Cut Bank by 5,
and into Great Falls during the evening. This front will have a
tight surface pressure with it and strong gusty winds are expected
north of the front. Temperatures will fall rapidly and Saturday
will see bitter cold temps across the north and central zones. Zelzer

Saturday night through Thursday...Very cold air will continue to
move into the region on Saturday night. With skies clearing out a
bit towards Sunday morning over North Central MT...morning
temperatures of 10 below to 20 below look good. The EC model
continues to forecast lows near 25 below...and depending on much
snow cover/how clear it actually gets could allow for temperatures
to fall this far. There will be some light snow Saturday night
through Sunday...but mainly in the mountains of Southwest MT. This
will be a short cold snap...with temperatures starting to warm back
up on Monday. For Tue thru Thursday...mainly I went close to climo
pops...as the GFS/EC have slightly different solutions...but with no
major storms expected...I did not want to go much above climo pops
at this time. Temperatures will begin to moderate...with highs
near/slightly above normal by the mid portions of next week. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  41  51   0 /  10  10  10  50
CTB  47  37  45  -7 /  10  10  30 100
HLN  49  35  49  20 /  10  10  20  40
BZN  47  31  48  29 /  10  20  20  40
WEY  38  28  38  23 /  20  30  30  60
DLN  49  35  48  33 /  10  20  20  30
HVR  45  31  43   1 /  50  10  20  80
LWT  52  37  51  10 /  20  10  10  40

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING until Midnight MST Friday Night Cascade...
Central and Southern Lewis and Clark...Northern Rocky Mountain
Front...Southern Rocky Mountain Front.

HIGH WIND WARNING until Midnight MST Friday Night For Route 287
over Norris Hill in Madison County.

&&

$$

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