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