Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 261533
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
933 AM MDT Wed Apr 26 2017

.UPDATE...

Satellite imagery this morning shows a strong Pacific Jet and
moist plume oriented along roughly 45N nosing into northern CA
with several embedded shortwave features to its north including
one moving quickly east across WA/OR. This feature will move into
the Northern Rockies and Western MT this afternoon and evening,
triggering another round of showers and thunderstorms as the
airmass destabilizes. Instability and shear are rather weak vs
vs the storm environment yesterday afternoon but low level
convergence along a N-S surface trough bisecting MT and plenty of
of low- level moisture in place along with a cold pool of temps
aloft should provide an environment for a fairly widespread
coverage of showers and weak thunderstorms this afternoon with
brief heavy rain and small hail (possibly in large quantities)
being the main threats. Hoenisch

&&

.AVIATION...
Updated 1155Z.
Another upper level disturbance will move through the region today.
Expect isolated rain/snow showers this morning to become more
widespread this afternoon. Areas of low clouds/fog will affect areas
may north of Great Falls this morning. Mountains will be obscured at
times through tonight. Brusda

&&

.PREV DISCUSSION...
/ISSUED 555 AM MDT Wed Apr 26 2017/
Today through Thursday...The next in a series of upper level
disturbances is beginning to approach western MT this morning. A
few showers will affect areas east of the divide this morning, but
precipitation is expected to become more widespread this
afternoon, especially west of I15. A few thunderstorms are
possible, but most storms should not be as strong as Tuesdays
storms. Areas of morning fog will also affect mainly North
Central MT this morning, while afternoon highs generally remain
about 4 to 8 degrees below normal. For later tonight/Thursday,
precipitation will try to move east slowly, but with the heating
of the day on Thursday, another round of mostly showers is
expected. Afternoon temperatures will continue the cooling trend,
with highs mostly in the 40s. Brusda

Thursday Night through Next Wednesday...A shortwave trough embedded
within broader longwave troughing will advance eastward over the CWA
Thursday night into Friday. Accordingly, mountain snow showers and a
rain/snow mix at lower elevations are expected during that period.
Even most locations on the plains and in the valleys may receive a
coating to inch or two of wet snow Friday morning. This includes Cut
Bank, Great Falls, Helena, and Bozeman. Somewhat drier weather is
expected Saturday as upper ridging builds eastward into the CWA.
However, unsettled weather looks to become more widespread again
Sunday through Tuesday of next week as a series of shortwave troughs
break-down the aforementioned ridging. Thereafter, Wednesday looks
to be primarily dry and warmer as another upper ridge builds-in from
the west. Near-normal lows are expected during the period, while
highs should remain below-normal through next week Tuesday. By next
Wednesday, highs should be closer to normal.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  36  47  32 /  80  50  60  50
CTB  48  34  44  31 /  80  50  70  50
HLN  56  36  50  33 /  70  40  40  30
BZN  53  35  46  30 /  60  70  60  40
WEY  43  29  37  21 /  80  80  60  40
DLN  52  32  46  28 /  50  80  50  30
HVR  54  36  48  33 /  30  50  70  50
LWT  49  34  43  31 /  60  70  70  50

&&

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

$$

weather.gov/greatfalls


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