Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 230413
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
913 PM MST Thu Jan 22 2015

.UPDATE...
Current forecast is on track...with just a few minor adjustments.
I have increased winds a bit this evening over the Rocky Mountain
Front and adjacent Plains. A few wind gusts in the 40 to 50 mph
range out over the Plains to the I-15 corridor. Also with the
breezy winds and clouds...temperatures will not cool off too much
more over Central and North Central MT...thus a slight upward
adjustment there for a few areas. In SW MT near the MT/ID
border...some clearing skies and a deep snow pack have allowed
temperatures to cool nicely...so I have lowered them a touch in
this region. Precipitation continues to fall over near the divide
and mainly in the mountains of SW MT. That trend should continue
through the overnight hours.

Looking ahead...the main weather concerns over the next few days
will be the periods of strong winds continuing over the Rocky
Mountain Front through much of the weekend...and the nice January
thaw that many areas will see by late in the weekend...with
widespread temperatures in the 40s and 50s by Sunday. Brusda

&&

.AVIATION...
UPDATED 0000Z.
Gusty westerly surfaces winds will gradually decrease with gusts to
20 to 30kts this evening as the pressure gradient weakens and a weak
upper-level weather system moves into southwest Montana. Clouds will
continue to increase with scattered rain/snow showers over higher
terrain, however an isolated shower or sprinkle is possible at
KBZN/KHLN/KLWT. Confidence is low regarding whether precip will fall
at the TAF sites so have added VCSH. VFR conditions are expected
across the area, however widespread mountain obscuration is
expected. MLV

&&

.PREV DISCUSSION...
/ISSUED 455 PM MST Thu Jan 22 2015/

Tonight through Saturday...A weak upper level disturbance moving
through the large scale upper level ridge over the Western US will
spread clouds across the region tonight with precipitation mainly
limited to some light snow showers along the Continental Divide
and a few isolated sprinkles/flurries over the Central/SW MT Mtns
tonight. Otherwise, dry conditions will prevail through Friday
across most of the forecast area. Windy conditions on the plains
will continue to diminish slightly through tonight though breezy
west to southwest winds will continue. Along the Rocky Mtn Front and
adjacent plains, wind speeds have diminished below critical
thresholds, but are expected to redevelop late Friday afternoon and
continue through Saturday as another upper level system moves over
the top of the longwave ridge across Western Canada. This system
will bring increasing winds again to areas further east across the
remainder of north-central MT as well on Saturday. Moisture with the
second weather system is also a little more robust and looks to
produce a period of steadier snow across the mountains, particularly
along the Continental Divide north of Rogers Pass. Valleys and
Plains could see some light rain showers with snow levels primarily
above 5000 ft Friday night and Saturday. Snow accumulations at/above
pass levels look to range up to 2 inches with 2-5 inches at
elevations above 7000 feet along the Continental divide north of
Rogers Pass. Hoenisch

Saturday Night through Thursday...A trough moves across Central
Montana and the Continental Divide during Saturday. Precipitation
chances climb across Central Montana but the system moves through
fairly quickly suggesting most places will not see much in quantity.
Precipitation looks to be rain at lower elevations and snow in the
mountains. Summer-like high pressure over the west coast builds
north late Sunday helping push most moisture out of the region for
Monday and Tuesday. The pattern holds into Wednesday as moisture
from a low pressure system in Mexico moves north through the Western
U.S. and into Southwest Montana Wednesday afternoon. Most moisture
from this system exits the region Thursday. West southwest winds
across much of the region look to remain in the 10 to 20 MPH range
throughout the period. High temperatures remain well above seasonal
averages with some locations in the low 50s this coming weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  34  43  37  48 /  10   0  10  20
CTB  33  42  35  46 /  10   0  10  10
HLN  33  36  27  42 /  10  10  10  20
BZN  24  33  23  44 /  10  10  10  20
WEY   4  30  13  29 /  20  20  20  30
DLN  25  39  27  47 /  10  10  10  20
HVR  29  39  33  46 /  10   0  20  20
LWT  31  42  31  46 /  10  10  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING until 5 AM MST Sunday Eastern Glacier...
Northern Rocky Mountain Front...Southern Rocky Mountain Front.

&&

$$

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