810 FXUS65 KTFX 110238 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 838 PM MDT Wed Oct 10 2018 .SYNOPSIS... Low clouds persist across the region this evening. Skies will begin to clear overnight, with temperatures dropping into the teens along the Rocky Mountain Front. Areas of dense fog are likely across western portions of North-central Montana. Drier conditions move into the region Thursday and Friday. Temperatures warm back to near seasonal averages Friday afternoon along with increasing winds. && .Update... Although light, precipitation has been more widespread at lower elevations, than originally forecast. Issued a short-term forecast to cover this. Lingering clouds will reduce the chances of morning dense fog; however, areas of reduced visibility in mist will still be expected. - Fogleman && .AVIATION... Updated 0000Z. Expect predominantly MVFR conditions, with persistent IFR conditions at KCTB. Throughout the area, a widespread low cloud deck, mountain obscurations are forecast. Reduced visibility is likely in mist and fog, particularly overnight and into the morning hours. Light snowfall can also be expected at KEKS. - Fogleman && .PREV DISCUSSION... /ISSUED 600 PM MDT Wed Oct 10 2018/ A cold and moist airmass remains in place over the region, associated with widespread low clouds. The upper level low responsible for snowfall the last two days is finally rotating away into the central plains. A subtle shortwave trough presently moving south through southern Alberta will cross the area tonight. This wave has little available moisture, but will be sufficient to produce light snow over mountain areas. The best chances for snow with this feature develop late tonight over the southwest Montana, where a few inches of new snow are possible over the higher mountains. Light winds and clearing skies create ripe conditions for areas of fog across western portions of North-central Montana. This fog could be dense in areas, and may impact travel along I15 early Thursday. If skies can clear enough late tonight over western portions of Glacier county, temperatures there could dip into the teens or lower by Thursday morning. Skies clear quickly on Thursday as the final trough axis passes, followed by strong subsidence and warming aloft. Winds begin to increase along the Rocky Mtn Front late Thursday night as NW flow aloft increases under weak upper level ridging with surface low pressure developing east of the Canadian Rockies. The upper level shortwave and surface low move SE through BC/AB Friday with strong gusty winds likely to develop across much of the area along with temperatures warming to near seasonal averages. Friday Night through Wednesday...A northeast-to-southwest oriented positively-tilted low pressure trough will deepen as it moves southeast over Montana Friday night through Saturday. The main jet/energy associated with this trough will move more so over the western and southwest Montana mountains, focusing the best chance for measurable snowfall there. This appears to be a fairly fast- moving system, so accumulations do not seem to be very heavy. The mountain snowfall forecast is in the 3 to 6 inch range, with an inch or two possible along the favored east-facing slopes of the Rockies. Of course, these amounts may need further adjustment as the event draws closer. Temperatures for most areas will struggle to get warmer than the 20s and mid 30s on Saturday as the passage of a strong Canadian cold front brings gusty northerly winds. As this system exits the area Saturday night through Monday, drier and warmer conditions are expected as a weak high pressure ridge spreads into western Montana; highs in the 40s to lower 50s are likely by Monday. However, another low pressure system will move southeast over the forecast area Monday afternoon through Monday night, but forecast models disagree on the strength of this system. Have therefore continued to broad-brush a chance of precipitation across the area. Not as much cooling is expected with this quick-moving system either. However, if the models deepen this shortwave similar to the one Friday night into Saturday, temperatures may need to be decreased and precipitation chances may need to be increased with subsequent forecasts. Drier and warming conditions return for Tuesday through Wednesday. Coulston && .PRELIMINARY POINT TEMPS/POPS... GTF 26 45 33 56 / 10 10 0 0 CTB 21 43 31 53 / 10 10 0 0 HLN 29 47 32 56 / 20 10 0 0 BZN 25 45 25 55 / 10 10 0 0 WEY 23 42 19 42 / 80 70 0 0 DLN 24 43 26 54 / 20 10 0 0 HVR 28 45 31 56 / 10 10 0 10 LWT 26 40 29 55 / 10 10 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls