Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 191718
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1118 AM MDT Sun Oct 19 2014

.UPDATE...

Satellite reveals high clouds along northern portions of the Rocky
Mountain Front associated with strong upper level winds. Surface
observations indicate wind gusts of 25 to 35 mph in this area as
lee troughing begins to develop. Other than these minor points of
interest, the forecast remains on track for a warm and mostly sunny
day. No changes were made to the forecast with this update. Nutter

&&

.AVIATION...
UPDATED 1718Z.
High pressure aloft will provide dry and stable conditions. Winds
will be generally light. VFR conditions prevail.

&&

.PREV DISCUSSION...
/ISSUED 520 AM MDT Sun Oct 19 2014/
Today through Tuesday...Ridging aloft will continue to provide dry
and stable conditions across the area today. Surface winds will be
generally light. The ridge axis shifts east to the Dakotas Monday
leaving behind an increasing southwest flow aloft over the area.
Moisture will be limited with this southwest flow aloft, the main
effect will be an increase in high clouds. An upper trof will move
over the Pacific Northwest Monday night/early Tuesday resulting in
isolated showers over the Rocky Mountain Front and over the
mountains of southwest Montana. Tuesday will find the upper trof
axis moving to the Continental Divide and a surface cold front will
push across the area. Showers will develop over the mountains and
become scattered as they move east and over the plains. Snow levels
will drop to around 7k feet with light accumulating snows possible
over the Rocky Mountains and over some of the higher peaks of
southwest Montana. Temperatures will be well above seasonal averages
today and Monday. Monday afternoon readings may reach record values
at some locations. Temperatures will drop to near seasonal averages
Tuesday as cooler air moves across the area.

Tuesday Night through Sunday...Forecast models differ on the timing
of a shortwave trough that is expected to move across Montana
Tuesday night. The ECMWF is the faster solution with the trough
exiting Tuesday night, while the GFS and Canadian solutions push the
trough across the Treasure State Tuesday night. Have gone with a
model blend and increased POPs to high chance for the mountains
across central/southwest Montana and slight chance to chance POPs
elsewhere. Snow levels will lower to around 6500 feet Tuesday night
with an inch or two of wet snow possible in the mountains along the
Continental Divide and southwest/central Montana. Precipitation will
be all rain for elevations below 6500 feet.

Drier and seasonal conditions will return for the middle to latter
part of the week under weak upper-level ridging. As the flow aloft
becomes more westerly, breezy conditions will develop along the
Rocky Mountain Front. In addition, increasing Pacific moisture will
keep chances for showers in the higher terrain along the Rocky
Mountain Front and Continental Divide. By late next week, some
forecast models hint at a chance for precipitation in the
plains/valleys associated with another trough of low pressure, but
there remains several differences between the forecast models.
Temperatures will be near to above seasonal averages through the
forecast period. MLV

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  71  47  76  46 /   0   0   0   0
CTB  70  41  77  45 /   0   0   0  10
HLN  71  42  73  45 /   0   0   0  10
BZN  68  35  71  39 /   0   0   0  10
WEY  59  27  61  32 /   0   0   0  20
DLN  69  39  72  44 /   0   0   0  10
HVR  69  39  74  42 /   0   0   0   0
LWT  71  43  76  47 /   0   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

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