Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 251800

Area Forecast Discussion
National Weather Service Great Falls MT
1200 PM MDT Tue Apr 25 2017


Numerous light showers and areas of rain continue to drift east
across N-central MT. Low clouds are producing areas of dense fog,
especially at elevations above around 3500 feet. Snow continues
over far southwest Montana, generally at and above mountain pass
level. Web cams indicate roads remain wet. The winter weather
advisory in effect for this are remains in effect, but remains set
to expire at noon. Short term model guidance indicates another
band of rain showers expected to develop later this afternoon
across N-central MT, associated with the shortwave trough
presently located upstream over the Canadian Rockies. Updated the
forecast to add widespread mid-elevation fog, and raised POPs/QPF
over N-central MT this afternoon. PN


Updated 1800Z.

Abundant moisture for widespread cloudiness through the period as
several waves ripple through the area. CIGS should tend toward VFR
or MVFR, but lower CIGS are possible at times. In addition, periods
of rain showers, mountain snow showers, and mountain obscuration are
expected. Isolated thunderstorms are possible this afternoon and
early evening, but confidence in a storm impacting an aerodrome is
low. Britton


/ISSUED 535 AM MDT Tue Apr 25 2017/

Today through Wednesday...Mostly cloudy skies will persist across
the CWA and snow levels should continue to fluctuate between roughly
5000 and 6000 feet MSL. As one shortwave trough exits Southwest MT
to the south and east this morning, bands of steadier snow should
diminish over that area by late morning. The winter weather advisory
until noon today for southern Gallatin County was expanded to
include southern Madison and Beaverhead counties, including Raynolds
Pass and Monida Pass. Slick, snow-covered roadways should linger in
these areas this morning. Another shortwave trough will skirt the
international border and Hi-Line today as it also moves generally
southward and eastward. Accordingly, scattered showers are expected
with the passage of this disturbance, especially over North-Central
MT. In addition, isolated thunderstorms are possible late this
morning through early evening and may move slowly once again,
resulting in localized swaths of heavier rainfall. Subtle shortwave
high pressure ridging and boundary layer stabilization via nocturnal
cooling should result in drier weather later this evening into
Wednesday morning. Thereafter, the potential for scattered showers
and isolated thunderstorms will increase late Wednesday morning
through afternoon as another disturbance overspreads the CWA from
the west. Near-normal lows and slightly below-normal highs are
expected through Wednesday.

Wednesday night through Tuesday...An overall unsettled weather
pattern will reside over the region during the extended period.
Light rain from Wednesday afternoon will continue through Wednesday
night. The rain could change to snow by Thursday morning at lower
elevations. However, the latest models indicate some precipitation
to continue into the day on Thursday, but some breaks in the
precipitation are possible, especially along/west of I-15.
Scattered/likely areas of precipitation will then continue Thursday
night through Monday, with the lowest chance for precipitation being
Sat/Saturday night. By Tuesday of next week, the GFS model progs a
fairly deep upper level trof of low pressure to develop over the
region, resulting in a fairly good spring snowstorm over Central MT.
However, it is too early to feel confident in this storm at this
time. Otherwise cool afternoon temperatures on Thursday and Friday
will warm a touch over the weekend, only to cool a bit by next


GTF  48  33  54  36 /  30  30  40  60
CTB  44  31  51  35 /  60  40  50  60
HLN  53  35  55  36 /  30  20  40  70
BZN  48  31  53  34 /  80  20  50  90
WEY  39  21  40  27 /  90  30  60  90
DLN  48  33  51  32 /  40  10  50  80
HVR  49  32  54  36 /  20  30  40  50
LWT  45  30  50  33 /  40  50  60  70


Winter Weather Advisory until noon MDT today Beaverhead...


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