Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 270525
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1025 PM MST Mon Jan 26 2015

.UPDATE...
Overall...a fairly quiet weather night expected over Montana
tonight...as an upper level ridge of high pressure continues to
reside over the region. A Chinook Arch is developing along the
front range of the Rockies...with mid/high level clouds expected
over North Central MT tonight. Gusty winds continue along the east
slopes...but wind speeds should remain below warning criteria.
Temperatures will be a few degrees cooler on Tuesday when compared
to today...but still well above normal.

The main concern over the next few days will be the increased
chances for rain/snow over Southwest MT late tomorrow afternoon
and tomorrow night. The latest NAM has precip as far north as
Bozeman. Then for the weekend the GFS/EC have different solutions.
The GFS is mostly dry/warm...and the EC is colder with some snow.
For now we have mostly split the difference...but changes are
possible for this weekend. Brusda

&&

.AVIATION...
UPDATED 0525Z.
An upper level high pressure ridge will remain over the region
through Tuesday and keep the region dry. Strong west winds aloft
will continue and keep strong and gusty winds across the Rockies.
VFR conditions will prevail through the next 24 hours.

&&

.PREV DISCUSSION...
/ISSUED 437 PM MST Mon Jan 26 2015/

Tonight through Wednesday...Upper ridge axis will cross the Divide
overnight resulting in continued dry and stable conditions.
Satellite imagery shows some mid and high clouds over eastern
portions of the state but they continue to slowly erode away.
Gusty surface winds along the Rocky Mountain Front and adjacent
plains will also decrease during the evening. Dry and mild
conditions on tap for the area again Tuesday along with breezy
afternoon winds. By Tuesday night, moisture and instability will
move into southwest Montana. Snow showers will develop over the
mountains with the valleys seeing a rain/snow mix. Precipitation
will continue over southwest Montana Wednesday before moving east
by late in the afternoon. Temperatures will be mild again on
Tuesday with readings well above seasonal averages. Afternoon
readings on Wednesday will be cooler but still above average.

Wednesday night through Monday...The main message with the period is
the latest ECMWF model run has flip-flopped with their solution over
the weekend and now has a cooler and wetter pattern than what it
forecast yesterday. The evening run of the GFS sticks with a milder
and drier pattern. Both the ECMWF and GFS model runs bring in colder
air Friday and Friday night. The latest ECMWF model run holds on to
the cold air over the weekend but the evening run of the GFS moves
out the cold air over the weekend. This leads to big temperature
differences between the two models with the ECMWF forecasting
highs mostly in the 20s Saturday and Sunday while the GFS has
highs mostly in the mid 30s to mid 40s. Did not want to jump on
the ECMWF bandwagon due to their flip-flopping so have only gone a
little cooler with forecast highs on Saturday. Did add a slight
chance of snow to the plains for Friday night and Saturday. For
the Wednesday night through Friday time frame went with the
inherited forecast of mostly dry conditions with highs in the mid
30s to mid 40s range. Blank

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  44  59  35  47 /   0   0  10  10
CTB  40  57  33  46 /   0   0   0  10
HLN  31  50  31  46 /   0   0  20  10
BZN  29  51  30  45 /   0   0  30  20
WEY  19  43  29  39 /   0   0  60  40
DLN  35  57  33  49 /   0   0  30  20
HVR  36  54  33  44 /   0   0  10  10
LWT  39  60  32  42 /   0   0  10  10

&&

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

&&

$$

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