Area Forecast Discussion
Issued by NWS Great Falls, MT

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061
FXUS65 KTFX 101550
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
850 AM MST Sun Dec 10 2017

.SYNOPSIS...

With an upper level ridge of high pressure to our west, expect
dry conditions across the region through Wednesday. Light winds
over Southwest MT will allow for cold temperatures to continue
along with patchy dense morning fog. Over North Central MT it will
be windy at times, allowing afternoon temperatures to climb into
the 40s and 50s for the next several days.

&&

.UPDATE...

Upper level ridging persists over the western USA. However,
variable mid- and high-level clouds will continue to move over
the top of the ridge and will advect over the region today and
tonight. Going forecast is in pretty good shape, but I have
updated to increase winds along the Rocky Mountain Front for
today through this evening. Also dded mention for areas of dense
freezing fog tonight and Monday night as there is no change in the
pattern that would rule out continued formation in the southwest
valleys each night. Finally, made minor tweaks to the diurnal
temperature curve and sky condition but wording in text products
remains the same. No further updates anticipated today. mpj

&&

.AVIATION...
Updated 1120z.
A northerly flow aloft will allow for some mid/high level clouds
to drift southward through the region through the period. Overall
VFR conditions will prevail, except for the Helena/Bozeman/West
Yellowstone areas where some fog could develop for a few hours
through 16z today. It could become as dense as it was on Saturday
morning in a few areas. Otherwise, gusty west winds will affect
much of North Central MT through this afternoon. Brusda

&&

.PREV DISCUSSION...
/ISSUED 425 AM MST Sun Dec 10 2017/
Today...Main concern today is patchy dense morning fog in the
valleys of Southwest MT. The fog should thin by late morning. Over
North Central MT gusty west winds are expected today. The winds
could create elevated fire weather concerns in the Havre/Fort
Belknap areas over the grass lands. However no highlights are
planned for at this time. Kept afternoon highs well below
guidance in the valleys of Southwest MT.

Tonight through Wednesday night...Dry conditions will prevail with
a ridge of high pressure just to our west. Again kept temperatures
below guidance over Southwest MT through the period. Held off on
mentioning fog, but it is possible at times over the Southwest.
It will remain mild over the north.

Thursday...The start of a changing weather pattern begins. Expect
more widespread westerly winds by late in the day across the
region. This will help mix out some of the colder air in the
Southwest valleys. A mix of rain/snow is possible over the western
mountains, especially by late in the day.

Friday into Sunday...Periods of rain/snow will move from west to
east through the region as weak upper level disturbances move
through. Precipitation amounts look light, but with the potential
for rain on top of snow covered roads, or wet daytime roads
freezing at night, some travel impacts are possible next weekend.
Afternoon temperatures are still progged to be a touch above
normal next weekend at this time. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  52  26  47  32 /   0   0   0   0
CTB  51  23  47  29 /   0   0   0   0
HLN  34  19  34  22 /   0   0   0   0
BZN  32  15  32  18 /   0   0   0   0
WEY  22   5  22   9 /   0   0   0   0
DLN  35  17  35  20 /   0   0   0   0
HVR  51  22  44  24 /   0   0   0   0
LWT  46  26  45  30 /   0   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

http://www.weather.gov/greatfalls



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