Area Forecast Discussion
Issued by NWS Great Falls, MT
FXUS65 KTFX 172053
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
253 PM MDT Mon Mar 17 2014
Tonight through Wednesday...Satellite imagery this afternoon shows
a vigorous upper level trough moving through the western
US with a mid-level circulation center noted just south of
Yellowstone Park. Widespread snow/snow showers will continue into
early this evening in the wake of the upper trough with drying
spreading south from the Canadian border later this evening and
allowing snow to diminish from north to south tonight. Potential
for brief periods of heavy/convective snow will diminish after 6pm
this evening as the airmass become more stable and best lift
associated with the upper trough move away from the region,
however snow showers will likely continue over the mountains
through much of tonight. Winter weather highlights continue
through tonight with main impact being over Mtn passes. Warm
ground/road surfaces have largely limited accumulations to grassy
surfaces at low elevations, however as temperatures fall into the
20s late this evening expect additional road surfaces at lower
elevations to become icy. Area remains under a NW flow aloft on
Tuesday with a very weak upper level disturbance moving through
early in the day, resulting in a slight chance for snow showers.
Temperatures will remain below seasonal averages on Tuesday with
warmer and drier conditions expected Wednesday as weak upper level
ridging builds in aloft from the west. Hoenisch
Wednesday night through Monday...A return to cooler and wetter
conditions is expected as the next shortwave trough moves into the
area Wednesday night and Thursday morning. While the system does not
look too impressive right now it will usher in a pattern change to
wetter conditions and temperatures below seasonal averages. This
will likely produce rain snow mixtures over the lower elevations as
temperatures peak near freezing through the weekend and then drop
back into the 20s and teens overnight. There continues to be some
timing differences of subsequent shortwaves across the area through
the weekend, however a general northwest flow aloft will allow for
showers to develop under the moist flow aloft. This will create a
generally wet and cool outlook through the bulk of the long
term...however by Sunday afternoon and evening a shortwave ridge of
high pressure will begin to move into the area and could provide
some temporary drying.
Upper level wave and associated surface cold front are currently
moving southeast through Central Montana. Band of heavy snow
accompanies the front for LIFR/IFR conditions for a short period.
Ahead of and behind the front weak convection is fueling scattered
showers with areas of rain and snow bringing temporary IFR/MVFR
conditions. Conditions will improve after 00Z Tuesday but low clouds
will linger across much of the forecast area through Tuesday morning
causing mountain obscurations. mpj
.PRELIMINARY POINT TEMPS/POPS...
GTF 24 40 24 47 / 40 30 0 0
CTB 21 38 24 44 / 10 20 0 0
HLN 26 40 24 48 / 80 20 0 10
BZN 24 38 17 44 / 80 30 10 10
WEY 15 34 7 37 / 60 20 10 10
DLN 20 35 18 44 / 50 10 0 0
HVR 27 44 25 51 / 20 30 10 0
LWT 23 38 22 45 / 90 40 20 10
WINTER WEATHER ADVISORY until 6 AM MDT Tuesday Blaine...
Broadwater...Cascade...Central and Southern Lewis and Clark...
Chouteau...Eastern Glacier...Eastern Pondera...Eastern Teton...
Madison...Meagher...Northern Rocky Mountain Front...Southern
Rocky Mountain Front...Toole.
WINTER STORM WARNING until 6 AM MDT Tuesday FOR ELEVATIONS ABOVE
5000 FEET FOR Cascade...Central and Southern Lewis and Clark...
Judith Basin...Meagher...Northern Rocky Mountain Front...
Southern Rocky Mountain Front.