Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 211724
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1124 AM MDT Mon Aug 21 2017

Updated Aviation

.SYNOPSIS...

Areas of mid and high level clouds will mostly move east out of
the region by this afternoon. High pressure aloft will then keep
skies mostly clear into Wednesday. Smoke will also thin out
somewhat today due to light north winds, but it will linger
through mid week along the Continental Divide. Temperatures will
warm from near normal today to around 10 degrees above normal by
Wednesday. A disturbance may then bring a chance of thunderstorms
to southwest Montana Wednesday afternoon and evening.

&&

.UPDATED DISCUSSION...

Mainly clear to partly cloudy skies and areas of smoke are
anticipated today. Winds will generally be light and variable with
high temperatures this afternoon in the upper 70s to low 80s. The
current forecast is on track so no changes were made. MLS

&&

.AVIATION...
Updated 1720Z.

VFR conditions will persist through the next forecast period. Winds
will also be light and variable shifting northeasterly. There will
be mid to high-level clouds moving across the northern half of the
state today, but clear conditions will prevail tonight through
Tuesday. Wildfire smoke will continue to impact areas across
southwest Montana including KBZN, KHLN and KEKS. Visibility may
lower to MVFR at times as a result of the smoke. MLS

&&

.PREV DISCUSSION...
/ISSUED 430 AM MDT Mon Aug 21 2017/

Today through Wednesday...Mid level clouds associated with a broad
shortwave trough will exit the area to the east this morning. The
likely mostly sunny/partly cloudy skies will make for good viewing
of today`s solar eclipse. However, there is a chance that another
batch of mid level cloudiness could move southeast out of British
Columbia and Alberta over north central Montana. A shift to light
northerly winds should also help move some of the smoke out of
the area today, keeping it closer to the Continental Divide in
the vicinity of the wildfires. A high pressure ridge will also
move into the forecast area tonight through Tuesday night, which
will help keep skies mostly clear. The ridge will also help warm
temperatures from near normal today to around 10 degrees above
normal by Wednesday. A disturbance will then move through the
ridge Wednesday afternoon, which will bring a chance of mainly
weak thunderstorms to southwest Montana.
Coulston

Wednesday Night through Monday...Period begins with an upper-
level trough digging southward and eastward from British Columbia
Wednesday night into Thursday. In addition, a Pacific cold front
accompanying this trough should sweep eastward over the CWA on
Thursday. Isolated to scattered showers and thunderstorms are
expected, especially Thursday afternoon and evening, when some
storms may be strong. The aforementioned upper trough looks to
continue digging over our region through Friday morning.
Thereafter, the trough should begin lifting northeastward Friday
afternoon as high pressure aloft builds-in from the south and
west. Accordingly, the potential and coverage of showers and
thunderstorms should dwindle on Friday. Drier weather is then
expected during the upcoming weekend and next week Monday as the
aforementioned high pressure ridge aloft continues building over
the area. Sightly above- normal temperatures on Thursday (e.g.
highs in the mid to upper 80`s for most) will be followed by a
cooler day on Friday, when the CWA will reside in a post-frontal
environment. On Friday, readings are expected to be several
degrees below-normal (e.g. highs generally in the mid 70`s to
near 80 degrees). Temperatures are then expected to rebound to
near or slightly above-normal this weekend through Monday of next
week.  Jaszka

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  81  50  90  55 /   0   0   0   0
CTB  78  47  88  50 /   0   0   0   0
HLN  82  51  92  57 /   0   0   0   0
BZN  83  47  89  51 /   0   0   0   0
WEY  76  36  80  40 /   0   0   0   0
DLN  80  46  88  50 /   0   0   0   0
HVR  80  50  89  53 /   0   0   0   0
LWT  78  50  86  53 /   0   0   0   0

&&

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

$$

weather.gov/greatfalls



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