826 FXUS65 KTFX 111047 AFDTFX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 347 AM MST Tue Nov 11 2014 .DISCUSSION... Today through Thursday...Light snow and flurries continue to affect much of the region this morning. However...most of the snowfall is very light...and not even showing up on radar. Thus any new snow accumulations today will generally be less than a quarter of an inch. Drier air will start to move into the region by late afternoon...thus mostly dry conditions are then expected tonight through Thursday morning. The next storm system will move into the region late Thursday afternoon. This storm system should mainly affect areas south of Great Falls to Lewistown line. The main concern for today through Thursday though will be the very cold temperatures and wind chills. Overnight lows will continue to average between 5 below and 15 below over the next few nights. If we do happen to clear out a bit towards sunrise...temperatures could be a few degrees colder. Wind chills are running close to 20 below this morning in many areas...thus the wind chill advisory will remain in effect. There is the potential that another wind chill highlight might be needed tonight...but winds will be a bit lighter. Thus we will continue to look at that closely today. Brusda Thursday night through Tuesday...The wet and cold pattern persists to start the medium range period. A strong shortwave swings across the area Thursday night and Friday bringing with it a large tap of Pacific moisture. Models place central Montana under the greatest threat for accumulating snow. By Friday night, the shortwave has moved rapidly to the east with snow lingering over the mountains of southwest Montana and over eastern portions of the county warning area. Saturday will be dry but the northerly flow aloft will keep cold air in place over the area. 500mb heights rise on Sunday as a shortwave ridge develops over western Montana. Warmer air returns with afternoon readings approaching the freezing mark. Upper ridging continues Monday though moisture moving through the ridge axis will allow isolated snow showers to develop over the Rocky Mountains and over the mountains of southwest Montana. Monday night and Tuesday will see an increasing chance for scattered snow showers as the next shortwave begins to approach the area from the west. Temperatures will remain well below seasonal averages to start the period. Afternoon readings will moderate Sunday as temperatures approach the 30 degree mark. Temperatures will be mostly in the 30s to start the week though these values continue to be below seasonal averages. The exception being southwest Montana where some areas will see readings in the 40s on Tuesday. && .AVIATION... UPDATED 0535Z. Areas of MVFR/IFR conditions in snow along with mountain obscurement will affect the forecast area except for north central Montana early in the period. Snow will mostly end by 12z. The main forecast problem late tonight through Tuesday evening will be what the sky condition will be. Guidance ranges anywhere from MVFR ceilings to no ceilings. Hence have low confidence in sky forecasts in the tafs. Also IFR visibilities in freezing fog will be possible Tuesday morning over portions of southwest Montana and central Montana. Blank && .PRELIMINARY POINT TEMPS/POPS... GTF 5 -15 8 -9 / 20 10 0 0 CTB 6 -15 8 -12 / 20 10 0 0 HLN 10 -8 12 -6 / 20 10 0 0 BZN 9 -17 10 -15 / 30 10 0 0 WEY 8 -17 13 -10 / 20 0 0 0 DLN 10 -13 12 -7 / 20 10 0 0 HVR 9 -17 8 -16 / 50 10 0 0 LWT 5 -13 10 -9 / 20 10 10 0 && .TFX WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY until Noon MST today for all of North Central and Southwest Montana. && $$ weather.gov/greatfalls www.twitter.com/NWSGreatFalls www.facebook.com/NWSGreatFalls