Area Forecast Discussion
Issued by NWS Great Falls, MT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS65 KTFX 211041

Area Forecast Discussion
National Weather Service Great Falls MT
341 AM MST Sun Jan 21 2018


A progressive westerly flow aloft will bring a series of weak
weather disturbances through the region this week. These systems
will bring areas of light precipitation to the mountains with
valleys and plains remaining mostly dry. Temperatures will remain
near or slightly below seasonal averages through much of this
week. However, forecast models suggest that a turn toward cooler
and unsettled conditions is possible toward next weekend.



Today through Tuesday...Dry and breezy conditions with seasonable
afternoon temperatures will prevail across the forecast area
today as shortwave ridging persists over the region. However,
progressive westerly flow aloft brings shortwave energy through
the region tonight and Monday. Widespread mountain snows are
expected along the Continental Divide with periods of light snow
developing over Southwest Montana on Monday. Models continue to
indicate that the heaviest snow accumulations will be in the
high mountains with only a few inches expected in the valleys. As
such, continue to feel that no winter weather highlights will be
required. Surface winds will increase across North Central Montana
and along the Rocky Mountain Front on Monday as an associated
surface low pressure system develops in southern Alberta, then
departs eastward with a weak Pacific cold front sweeping through
the region. The upper level shortwave continues moving eastward
Monday night with ridging aloft developing on Tuesday for mostly
dry and breezy conditions over the plains. However, westerly flow
aloft will continue to bring Pacific moisture inland for light
orographic snows over the northern Continental Divide. mpj

Tuesday night through Sunday...Medium range models remain in very
good agreement that a progressive flow aloft will move a broad
upper level ridge over the state Tuesday evening through Wednesday
for continued mostly dry and breezy conditions. Guidance suggests
that the warmest temperatures of the week can be expected on
Wednesday. From Wednesday night through Friday, a broad upper
level trough moves inland across the western USA, with the bulk of
associated energy and precipitation remaining south of Montana.
However, abundant Pacific moisture entrained in the upper trough
will bring widespread precipitation to Western Montana and the
mountains of the Continental Divide. Additionally, unsettled
conditions due to lower pressure aloft will allow a chance for
some light precipitation to move out over the plains at times
Wednesday night and Thursday. On Thursday night, models indicate
that a moderately strong surface cold front will sweep through the
region leaving a cooler airmass and unsettled condtions in place
Friday and Saturday. By next Sunday the progressive flow aloft
will usher in another upper level ridge allowing temperatures to
rebound once again. mpj


Updated 0600Z.

VFR conditions are generally expected for the next 24-hours as
high pressure builds across the region. Sites across southwest
MT...including KEKS and KBZN...may briefly see fog Sunday
morning...bringing some MVFR to IFR conditons. Breezy
southwesterly to westerly surface winds will persist on the North-
Central MT plains through much of the period...although gusts
should remain below any high wind criteria. Lastly, upslope snow
and mountain obscuration along the Rocky Mountain Front should end
between 12Z and 18Z/Sun. Anglin


GTF  36  29  37  22 /   0   0  10  10
CTB  35  24  36  20 /   0  10  10   0
HLN  29  11  29  11 /   0  10  20  10
BZN  25   4  26   9 /   0  10  40  20
WEY  23   3  23   4 /   0  20  70  40
DLN  27  19  28  11 /   0  20  40  10
HVR  29  15  33  13 /   0   0  10   0
LWT  32  21  34  18 /   0   0  20  10



$$ is the U.S. government's official web portal to all federal, state and local government web resources and services.