Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 222023
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
223 PM MDT Sun Oct 22 2017

.SYNOPSIS...

Strong winds will ease tonight but remain breezy through Tuesday,
especially over the plains. Simultaneously, precipitation along and
near the Continental Divide, and the Southwest Montana mountains,
will become scattered tonight and then end on Monday. Dry weather is
then expected through Tuesday, as are moderating temperatures.

&&

.DISCUSSION...

Rest of today through Tuesday...A weather disturbance will exit our
CWA to the east this afternoon and evening. In its wake, a high
pressure ridge builds-in from the west through Tuesday. This pattern
will allow surface winds to ease this evening as flow aloft weakens
and the MSLP gradient relaxes in response to the aforementioned
ridge. Will keep the high wind warning in place for now and let
the evening shift reevaluate the situation later today. Upslope
precipitation along/near the Continental Divide and across the
Southwest MT mountains will become more intermittent this evening
before tapering-off on Monday. Elsewhere, just a few showers are
possible through this evening, while even a stray thunderstorm or
two cannot be completely ruled-out over Hill and Blaine Counties.
Dry weather is then expected area-wide Monday night and Tuesday
as stabilizing high pressure gains firm control. Low temperatures
will be near or slightly-above normal through the short term
period. Highs will be near-normal today and Monday before
moderating to about 10 degrees above-normal on Tuesday.
Jaszka

Tuesday Night through Sunday...A fast moving shortwave trough
embedded in the northwest flow aloft will drag a cold front
through the region Wednesday evening. A period of strong southwest
winds appears likely to develop in advance of the frontal
passage, possibly reaching high-wind criteria. Models are
beginning to converge on the timing for this system, but
confidence remains low regarding temperatures as winds shift to
the north and produce upslope- enhanced precipitation across much
of N-central MT. A blend of model solutions does bring temperature
below freezing Wednesday night, with snow levels lowering to the
plains/valleys. The trough moves quickly, limiting potential snow
amounts to around 1 inch at lower elevations. High amplitude
ridging over the western U.S. will provide a dry northerly flow
over Montana to end the week, with temperatures returning to near
seasonal averages.
PN

&&

.AVIATION...
Updated 1700Z.

VFR expected at TAF sites next 24-hours. Strong westerly flow aloft
will shift to northwesterly and ease somewhat after 00Z/Mon as a
weather disturbance exits to the east and high pressure aloft builds-
in from the west. Strong and gusty southwesterly to westerly surface
winds are expected through this early evening, especially over North-
Central MT. Areas of mountain wave turbulence and low-level wind
shear are forecast. Rain and/or snow is expected along/near the
Continental Divide and across the mountains of Southwest MT.
Mountains will be obscured at times. Expect slowly improving
conditions after 06Z/Mon.
Brusda/Jaszka

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  39  57  39  66 /  10   0   0   0
CTB  36  54  37  65 /   0   0   0   0
HLN  39  57  34  65 /  20   0   0   0
BZN  34  57  30  63 /  20   0   0   0
WEY  26  46  22  53 /  50   0   0   0
DLN  32  55  30  62 /  20   0   0   0
HVR  36  58  33  65 /  10   0   0   0
LWT  35  52  33  66 /  20   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 10 PM MDT this evening Blaine...
Broadwater...Cascade...Central and Southern Lewis and Clark...
Chouteau...Eastern Glacier...Eastern Pondera...Eastern Teton...
Fergus...Hill...Jefferson...Judith Basin...Liberty...Meagher...
Northern Rocky Mountain Front...Southern Rocky Mountain Front...
Toole.

High Wind Warning until 10 PM MDT this evening Madison.

&&

$$

weather.gov/greatfalls



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