Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 280350
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
950 PM MDT Tue Jun 27 2017

.UPDATE...
Updated forecast is out. Main changes this evening where to
freshen pops via current radar. Mostly scattered showers
left...with an isolated lightning strike. This will continue
overnight over Southwest MT and across southern Judith
Basin/Fergus counties. Otherwise, showers/thunderstorms move
across Southwest MT through the day on Wed while increase during
the afternoon hours over North Central MT. Afternoon temperatures
will be seasonable. The chances for rain showers continue Wed
night especially over North Central MT. The upper level trof exits
the region around mid day Thursday...so afternoon temperatures on
Thu could be a bit warmer than NAM numbers...rather closer to
warmer GFS numbers. Midnight shift will look at this closer.
Brusda

&&

.SYNOPSIS...
A cold front dropping south out of Canada will keep scattered
showers and thunderstorms going across much of the area through
early this evening. The strongest storms may produce gusty winds
and hail. Unsettled weather may linger into Wednesday before drier
air moves in late in the week. Temperatures will cool some
through Thursday, then increase once again over the weekend.

&&

.AVIATION...
Updated 2345Z.
Scattered thunderstorms will move through Central and Southwest MT
this evening. The main threat will be gusty winds, small hail, and
occasional lightning. Most storms will diminish by 08z. Generally
VFR conditions will prevail for most during the day Tue, but another
round of showers/potential thunderstorms are possible after 20z Tue
over Southwest MT. Brusda

&&

.PREV DISCUSSION...
/ISSUED 245 PM MDT Tue Jun 27 2017/

Rest of today through Thursday...Radar and satellite imagery
continues to light up with showers and thunderstorms across the
southern third of our CWA at this time. This activity is associated
with a s/w swinging through the area at this time. The atmosphere
remains weakly/moderately unstable, but shear continues to be
somewhat weaker and it still looks like the overall severe threat
today will be tampered by a lack of better shear. Still, the
strongest cores through this evening could produce gusty winds and
hail. A brief shot of drier air moves in tonight with a gradual
decreasing trend in showers/storms.

On Wednesday/Thursday, an upper low over central Alberta will
finally pivot SE and push into the NRN Plains. This will send
another strong cold front through the area as the upper level flow
turns NW. The front will move through Wednesday evening/night.
Lingering moisture in the NW flow will keep at least isolated
showers and t-storms going into Wednesday night, possibly
lingering into Thursday. Although, in general, the coverage should
begin to decrease by Thursday. In the wake of the front,
temperatures will fall back close to or below normal by Thursday.
MARTIN

Thursday night through Monday night...The upper level pattern
will remain very progressive in nature, with no one single trough
or ridge remaining in place for more than 24 to 36 hours at a
time. High temperatures will warm each consecutive day through
Monday, with readings generally rising above climatological norms
by the weekend, and well above normal highs for the day on Monday.
While sporadic chances for showers/thunderstorms will be possible
through the first half of the long term (through Saturday
evening), precipitation amounts look to be very light (with the
exception of those areas that see a thunderstorm, which could
produce some marginal QPF amounts). The biggest concern in the
long term (at this time) will be the day on Monday, as upper level
ridging breaks down, dry/breezy downsloping winds develop, and
high temperatures climb into the 80s to low 90s. The combination
of unseasonably warm temperature, low minimum RHs, breezy
west/southwest winds, and the ongoing curing of fuels...will
create at least some elevated fire weather concerns (at this time)
for the day and into the evening hours on Monday (especially
across North Central Montana). Given that Monday will be the eve
of Independence Day, felt it was prudent to mention my concerns
for fire weather conditions, despite it being at the end of the
long term period. - Moldan

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  77  49  70 /  10  20  40  30
CTB  49  75  48  69 /   0  30  30  20
HLN  54  79  51  75 /  10  20  30  20
BZN  50  73  45  72 /  30  30  20  20
WEY  42  64  37  65 /  30  70  40  10
DLN  48  72  44  71 /  30  40  20  10
HVR  53  81  52  72 /   0  20  20  30
LWT  52  75  47  68 /  10  20  20  30

&&

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

&&

$$

weather.gov/greatfalls



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