Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 132105
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
205 PM MST Mon Nov 13 2017

.SYNOPSIS...

A weather disturbance and accompanying cold front from the Pacific
Northwest will sweep eastward over our region this evening into
Tuesday morning. The result will be gusty winds, especially along
and near the Rocky Mountain Front. In addition, periods of
accumulating and blowing snow will impact the Continental Divide and
Southwest Montana mountains. At lower elevations, just a few rain
and/or snow showers are possible this evening into Tuesday morning.
An overall improvement in weather conditions is then expected later
Tuesday into Wednesday as high pressure overspreads our area in the
wake of the disturbance.

&&

.DISCUSSION...

Rest of today through Tuesday...A shortwave trough continues to
approach our region from the Pac NW. The axis of this disturbance
will near the Continental Divide in southern BC/AB and the divide in
MT by this early evening. Thereafter, the disturbance will continue
moving east-northeastward and exit our CWA by early Tuesday
afternoon. Accordingly, the Pacific cold front accompanying this
disturbance will sweep eastward over the region this evening through
Tuesday morning. Atmospheric profiles still look to support a period
of strong winds along the Rocky Mountain Front and in eastern
Glacier County this evening into the predawn hours of Tuesday, so
will keep the high wind warning in place there. Otherwise, breezy
winds are expected at most other locations. In addition, this
pattern will yield periods of accumulating and blowing snow along
the Continental Divide and the SW MT mountains through Tuesday. The
winter weather advisory for Marias Pass also remains in effect due
to the expectation of difficult travel conditions this evening into
Tuesday morning. Otherwise, the aforementioned cold front may
generate isolated rain and/or snow showers at lower elevations this
evening into Tuesday morning. Above-normal highs this afternoon and
warmer than normal lows tonight will be followed by near or slightly
below-normal highs Tuesday.

Tuesday night through Wednesday...Overall, fair weather and lighter
winds are expected during this period as a high pressure ridge aloft
builds-in from the Pac NW. Temperatures will be near or slightly
below-normal.
Jaszka

Wednesday night through Sunday...The next in a series of Pacific
cold fronts will cross the area late WED/THU. This one looks very
similar to the front expected to cross the area later today/tonight,
bringing a quick round of precip and gusty winds. Given the
progressive nature of the front, widespread/significant impacts are
not expected. That said, Marias Pass/GNP may once again be a
candidate for at least minor travel impacts due to snow/blowing
snow. Of note, too, there may be a period of moderate to heavy snow
showers across parts of SW MT Thursday morning/afternoon with some
impacts, especially passes along the MT/ID border and in the W.
Yellowstone area.

In the wake of that front, the main focus through the weekend will
be wind and temps. The models continue to struggle with what will
likely be another large, upper low sitting off the West Coast. The
question is whether is sits off the coast leading to mild and
breezy/windy conditions or whether it quickly moves onshore, also
leading to breezy/windy conditions, but a shorter-lived period of
milder temps. For now, the forecast didn`t sway too much from the
previous forecast in order to keep from flip-flopping too much. The
main takeaway here is confidence is lower over the weekend and we`ll
hold off on getting too specific on temps/wind/precip chances for
now. That said, the potential still exists for above to well-above
normal temps and, for some, strong winds. MARTIN

&&

.AVIATION...
Updated 1737Z.

Westerly flow aloft and primarily VFR expected next 24-hours. A
weather disturbance aloft and accompanying Pacific cold front will
advance eastward over the region this evening through early Tuesday
morning. This frontal passage will be accompanied by surface winds
shifting from southwesterly to westerly at many locations. In
addition, a period of gusty winds is expected ahead of and behind
this front. This will especially be the case along the Rocky
Mountain Front and across the North-Central MT plains. Lastly,
periods of snow and mountain obscuration are expected along the
Continental Divide and SW MT mountains during the TAF period, while
isolated rain and/or snow showers are possible over the plains and
valleys this evening into Tuesday morning.
Jaszka

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  35  42  26  43 /  20  10   0   0
CTB  33  39  20  37 /  10  10   0   0
HLN  30  41  22  40 /  30  20   0   0
BZN  30  40  18  41 /  30  30   0   0
WEY  28  35  17  37 /  50  60  10  10
DLN  31  39  20  41 /  20  20   0   0
HVR  33  43  17  38 /  10  10   0   0
LWT  33  41  22  43 /  10  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning from 6 PM this evening to 6 AM MST Tuesday
Eastern Glacier...Northern Rocky Mountain Front...Southern Rocky
Mountain Front.

Winter Weather Advisory from 6 PM this evening to 9 AM MST
Tuesday above 5000 feet for Northern Rocky Mountain Front.

&&

$$

http://www.weather.gov/greatfalls



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