Weather Service Report


944 
FXUS65 KTFX 211146
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
446 AM MST Sat Jan 21 2017

UPDATE AVIATION

.DISCUSSION...

Today through Monday...Current water vapor imagery showing nicely
our weather setup for today. With a weak cut off low in the
Dakotas...and a large upper level low spinning just off the coast
of the Pacific NW...we find ourselves stuck in the middle of
weather systems. The overall result will be light winds and near
normal temperatures for today. A ridge of high pressure to our
south slowly builds northward throughout the day. As that
happens...moist southwest flow enters the state from southwest to
northeast. This could bring a few scattered light snow showers 
across the southwest during the day...with snow chances moving 
northeast tonight into Sunday morning. By Sunday afternoon the 
mentioned high pressure ridge enters into the state...and 
diminishes chances for snow...except across the southwest where 
moist and breezy southwest flow continues through the day. The 
mentioned low off the coast of the western US then sends a 
disturbance with surges of moisture to the state Sunday night 
into Monday. Then a weak push of cold Canadian air could be 
experienced later in the day Monday. These disturbances will 
return widespread chances for light to scattered moderate snow 
during this time period. At least light snow accumulations are 
possible by Monday evening...mainly across northern...western...and
southern portions of the CWA. No highlights issued yet with this 
storm...as models still trying to pinpoint the track of the upper 
level disturbances...and intensity. And although most areas will 
have at least a slight chance of snow...right now looks like 
southern areas will have the better chances. Stay tuned for 
updates. Winds remain light for today. The southwest flow could 
bring some increase winds...especially across the southwest...on 
Sunday. With no major airmass changes...near normal temps are 
expected today into Sunday. Colder air from Canada may bring 
slightly below normal temps for Monday. Anglin

Monday night through Saturday...A broad upper level trough with axis 
from Central Canada SW into the Western US will bring cool and 
unsettled conditions early next week, followed by dry northerly flow 
aloft as the trough progresses east into the central US with a ridge 
amplifying along the west coast and pushing inland by the end of 
next week. Shortwave energy tracking east from southern ID into WY 
Monday night will bring widespread light snow to southern portions 
of the forecast area while a northerly flow with embedded energy 
also spreads light snow showers across areas to the north Monday 
night through Tuesday night. Amplifying ridge to the west will bring 
dry conditions from late Wednesday into next weekend with 
temperatures moderating from somewhat below seasonal averages early 
next week to slightly above average by next weekend. Surface high 
pressure will also strengthen over the interior western US late next 
week and will likely lead to the redevelopment of temperature 
inversions in the SW MT valleys, likely leading to lingering cold 
temperatures and potential air quality issues in some SW MT valleys. 
Hoenisch

&&

.AVIATION...
Updated 1200Z.

VFR conditions mainly expected during the forecast period...with
periods of patchy morning fog...and scattered light snow possible.
Light winds and limited cloud cover will bring some patchy fog to
a few sites this morning. MVFR to brief IFR conditions are 
possible. Much of the state will then see VFR conditions through 
the day...although some light snow showers may develop across the 
southwest...perhaps bringing MVFR to brief IFR conditions at 
times. Scattered light snow may push north and east tonight into 
early Sunday morning...perhaps bringing brief snow showers to area
sites. Once again MVFR to brief IFR conditions are possible. 
Isolated snow showers could linger late in the period...with some 
patchy fog possible to areas that can clear out. Anglin

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  34  20  34  19 /  10  20  10  20 
CTB  33  18  32  17 /  10  20  10  50 
HLN  29   9  26  11 /  20  20  10  30 
BZN  28   7  28   9 /  20  30  10  30 
WEY  25   6  22  12 /  30  40  40  50 
DLN  31  12  32  15 /  20  20  20  30 
HVR  33  18  30  18 /   0  10  20  20 
LWT  35  19  35  18 /  10  10  10  20 

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

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Western Regional Climate Center, wrcc@dri.edu