Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 300928
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
328 AM MDT SAT JUL 30 2016

.DISCUSSION...

Today through Monday...Overall a warm and dry weekend with
elevated fire danger returning. Current WV imagery starting to
show dry air entering into SW MT with some limited moisture in
central MT...and the monsoonal moisture...that has been monitored
for days...stopping just short of the NV and ID border. Upper
level low will push into Canada today bringing warm SW flow to the
area. Today we find out if we are able tap into any of the
monsoonal moisture to our south. Current model runs are showing
the answer is probably not as much as we would like. Far SW MT may
see a few afternoon thunderstorms from the northern extend of this
moisture...with generally only a few isolated mountain storms
elsewhere. Northern MT may be the exception...as dry air attempts
to push out the not as dry air this afternoon a pseudo warm/dry
line type front may set up. With ample instability...shear from an
increasing jet...and some increased dewpoints from se flow...a few
isolated thunderstorms may develop across the Highline area this
afternoon and evening. All areas will see warm temperatures
today...with high temps across the lower elevations expected to
reach into the 90s. A weak cool front associated with the upper
low in Canada will then push across the region tonight through
Sunday. This looks to be a fairly dry front...with only a few
areas across the north and far south seeing chances for isolated
thunderstorms. The main story with this front will be the elevated
fire danger concerns for Sunday...as min RH values will drop into
the teens...and gusty westerly winds will be found. For a more
detailed discussion about the fire danger this weekend see the
Fire Weather Discussion below. The main take away is those with
outdoor plans should be mindful of errant sparks...attend and put
out all campfires...and hold off outdoor burning this weekend. Dry
air with some continued westerly breezes will continue into Monday
as brief ridging begins to approach the area. Temps for Sunday and
Monday will be slightly cooler then the 90s on Saturday...but
still could be near to slightly above climate normals. Anglin

Monday Night Through Saturday...Upper level ridging briefly shifts
east across the region Monday night through early Tuesday with
temperatures warming back to somewhat above average levels again by
Tuesday afternoon. A compact upper level low moves inland along the
WA/BC border Tuesday and continues east along the MT/AB border
Tuesday night. Diffluent SW flow aloft and incoming upper level jet
maximum ahead of the low will focus greatest large scale lift across
N-Central MT Tuesday afternoon and evening with a cold front also
looking to shift east across the region during the late afternoon
period. This could create a favorable set-up for potentially severe
convection Tuesday afternoon/evening if enough moisture can return,
which is appearing more likely with an inverted surface trough
setting up across S-central/central MT Tuesday and E/NE low level
flow ahead of the front across the N-central MT plains. Drier and
cooler air moves in behind the front late Tuesday night through
Wednesday as the upper low tracks east along the MT/SK border with
just a small chance for showers along the Canadian border. Thursday
through Saturday period looks to gradually warm as heights build
around an upper level ridge centered over the central CONUS with
weak troughing oriented along the West Coast. Hoenisch

&&

.AVIATION...Updated 0520Z.

VFR conditions will prevail through Saturday evening as dry
Northwest flow aloft backs to Southwesterly and gradually increases
as a broad upper level trough moves into BC. At the surface, a trough
of low pressure will shift east across the Northern Rockies and MT
Saturday with light east winds tonight becoming W to SW Saturday
and increasing during the afternoon period. Hoenisch

&&

.FIRE WEATHER...

Warm and dry conditions to bring elevated fire danger this
weekend. Southwest flow will bring very warm and drying
conditions today across the forecast area. Min RH values today
will begin to lower into the teens and 20s...with high temps expected
to return into the 90s. Widespread gusty winds are not expected
for today...although some increasing breezes will be found across
southern and western portions this afternoon and evening. Only
isolated thunderstorms are expected for today...mainly across the
north...far south...and in the higher terrain. A weak cool front
will then push across the region tonight through Sunday. This will
bring slightly cooler...but still warm...temperatures along with
very dry conditions...and only isolated thunderstorms in the far
south and north. Morning RH values will struggle to rebound
Sunday...and min RH values will be in the teens to low 20s. Gusty
westerly winds may also be found for Sunday...with gusts 20 to 25
mph possible. Despite these favorable fire weather
conditions...fuel status across local fire zones remains near to
slightly below critical values. Because of the uncertainty in fuel
status...and the desire to see slightly stronger sustained
winds...will hold off on fire weather highlights at this point.
However...those with outdoor plans should be mindful of errant
sparks...attend and put out all campfires...and hold off outdoor
burning until fire danger improves. Anglin

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  93  60  88  50 /  10   0  10  10
CTB  89  54  78  48 /  10   0  10  20
HLN  94  63  90  54 /  10  10  10  10
BZN  92  57  90  48 /  10  10  10  10
WEY  83  53  80  42 /  10  20  20  10
DLN  90  56  87  47 /  10  10  10  10
HVR  92  61  86  53 /  20  20  10  20
LWT  88  62  87  52 /  10  10  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
&&

$$

weather.gov/greatfalls



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