954 
FXUS65 KTFX 170528
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1125 PM MDT Wed Oct 16 2019

Aviation Section Updated.

.SYNOPSIS...

Seasonably warm and breezy conditions the remainder of today into
tonight. A series of disturbances will then bring cooling
temperatures and an increasing chance of mountain precipitation
Thursday into Friday, with even stronger winds for the plains.
Overall, winds should decrease over the weekend, but a low
pressure trough will bring below normal temperatures and a good
chance of precipitation to the entire region.

&&

.UPDATE...

High and mid- level clouds are streaming into the region as 
another Pacific system approaches from the west. This system and 
its attendant cold front will move through tomorrow, bringing 
breezy to windy conditions and rain/mountain snow for locations in
the southwest and along the Continental Divide. Only minor 
changes were made for the update as the current forecast remains 
on track.

&&

.AVIATION...
Updated 1125 PM MDT Wed Oct 16 2019 (18/06Z TAF Period) 

VFR conditions prevail overnight as scattered high clouds move 
across the Rocky Mountains. Clouds will gradually thicken and lower 
early Thursday as a cold front advances toward Western Montana. MVFR 
conditions are likely for the southwest terminals later Thursday 
afternoon with showers, then periods of rain or rain/snow mix 
Thursday evening. Expect mountain wave turbulence and scattered low-
level wind shear across the region.

&&

.PREV DISCUSSION...
/ISSUED 217 PM MDT Wed Oct 16 2019/

Remainder of this Afternoon through Friday Night...

Upper-level ridge axis over central Montana will speed up as it
moves east the next 24 hours. Lifting upper-level disturbance with
attendant surface cold front moves from west to east across the 
region Thursday, bringing clouds and a chance of rain and high-
elevation snow to southwest Montana. The front will represent the
leading edge of stronger westerly winds that will persist into
Friday, while for southwest Montana the front will help to focus a
short-lived period of moderate to heavy snow over parts of 
southwest Montana (mainly Madison and Gallatin mountain ranges) 
given the progressive nature of the front, very low stability, and
high moisture. By Thursday night, another digging upper shortwave
will bring increased high-elevation snow along the Continental 
Divide and strong to high winds to the Rocky Mountain Front. Given
the increased likelihood of what appears to be shaping up for a 
low- end high wind event, we have issued a High Wind Watch from 
midnight Thursday night to midnight Friday night along the Rocky 
Mountain Front, with the watch extending out onto parts of the 
adjacent plains near the Canadian border. Breezy conditions 
continue through the remainder of the late Friday night as brief 
and transitory shortwave ridging moves through ahead of the next 
disturbance. 

Saturday through next Wednesday...

Low pressure over the Gulf of Alaska will help deepen a broad 
upper level low pressure trough over the western and central 
United States for the weekend. This will help spread a good chance
of precipitation over the entire forecast area, mainly measurable
snow in the mountains and rain possibly mixing with snow at times
at lower elevations, as temperatures stay 10 to 15 degrees below 
normal. A weak high pressure ridge will move into the area from 
the west Monday, which will keep the main chance for 
precipitation in the mountains, bring a return to gusty westerly 
downslope winds, and help warm temperatures closer to normal. 
However, this less active period will be short-lived, as another 
low from the Gulf of Alaska re-establishes the low pressure 
trough over the central United States Tuesday into Wednesday. This
will bring a another widespread chance of precipitation with 
cooler than normal temperatures. These disturbances will need to 
be monitored for potential winter weather highlights. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  45  60  39  53 /   0  10  20   0 
CTB  41  52  35  47 /   0   0   0   0 
HLN  41  58  36  52 /   0  30  40  10 
BZN  38  62  32  52 /   0  40  80  40 
WEY  25  52  22  40 /   0  40  70  60 
DLN  40  56  31  47 /   0  50  70  20 
HVR  41  62  36  56 /   0   0   0  10 
LWT  45  62  36  51 /   0  10  50   0 

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from late Thursday night through Friday evening 
Eastern Glacier...Eastern Pondera...Liberty...Northern Rocky 
Mountain Front...Southern Rocky Mountain Front...Toole.

&&

$$

http://www.weather.gov/greatfalls