889 FXUS65 KTFX 092212 AFDTFX Area Forecast Discussion National Weather Service Great Falls MT 412 PM MDT Sun Jun 9 2019 .UPDATE... Increased POPs to have at least a slight chance of isolated showers and thunderstorms over much of north-central MT, especially for areas north through east of Great Falls. This change was based on latest radar, lightning, and SPC mesoanalysis trends. Used WRF ARW POPs as a starting point and made manual adjustments to expand slight chance POPs over a larger area. Eventual stabilization of the boundary layer via nocturnal cooling should allow these showers and thunderstorms to end by late this evening. - Jaszka && .SYNOPSIS... A gradual warming trend occurs through Tuesday. Simultaneously, isolated showers and thunderstorms are possible, especially during the afternoon and early evening hours of each day. Noticeably warmer temperatures return this Wednesday through upcoming weekend. After a dry day on Wednesday, an overall increase in shower and thunderstorm potential is expected Thursday through next weekend. && .DISCUSSION... /Issued at 244 PM MDT Sun Jun 9 2019/ Rest of today through Monday...Northwesterly flow aloft persists as high pressure aloft builds slowly from the west. Multiple shortwave disturbances embedded in the flow aloft traverse our CWA. Isolated showers and thunderstorms are possible, especially during the afternoon and early evening hours of today and tomorrow. Areas over and near higher terrain have the best chance of experiencing precipitation since daytime heating of our mountains will likely be the primary trigger of any shower or thunderstorm. Despite a gradual warming trend, temperatures will tend to be below-normal through Monday. - Jaszka Tuesday through Sunday...main forecast concerns and impacts to the region are primarily focused at the end of the work week and into the weekend when more widespread precipitation chances develop across portions of the CWA. H500 ridge axis generally orientated along the Western CONUS/Canadian coastlines Tuesday morning will slowly slide east towards the Northern Rockies through the day on Wednesday, before a shortwave moves ashore the Pacific Northwest/British Columbia Wednesday afternoon/evening and begins to breakdown and flatten out the aforementioned ridge. Moist and unstable northwest flow aloft will remain over the region for the day on Tuesday. This setup will promote chances for isolated to scattered showers, possibly a thunderstorm, Tuesday morning and afternoon over primarily Northern and Central Montana (especially over the mountains of Central Montana). As the ridge axis moves toward the region Tuesday night/Wednesday, expect dry and pleasant conditions to overspread most of the CWA for the day on Wednesday. High temperatures on Wednesday will finally return to normal or slightly above normal, which will be a nice sight after below normal temperatures this weekend and to start the upcoming work week. As the ridge flattens out Wednesday night, zonal flow will develop across the Northern Rockies and generally remain in place into the Father's Day Weekend. Models continue to hint at an extended period of precipitation chances from Thursday and into the weekend across portions of the CWA, however, timing and placement of the waves rippling through the zonal flow aloft still exist and have created uncertainty in the exact timing/duration/location of precipitation over this timeframe. At this time, areas along/near the Continental Divide and mountains of Southwest Montana have the best opportunities for showers/thunderstorms to end the work week and into the weekend. - Moldan && .AVIATION... Updated 1038 AM MDT Sun Jun 9 2019 (18Z/Sun TAFs) A NW flow aloft will persist over the region through Monday with VFR conditions prevailing under mainly scattered cloud-cover. A few isolated showers are possible this afternoon and early evening, mostly across north-central MT and the central MT mountain ranges such as the Little Belts, which could bring some very localized MVFR and mtn obscuration. Breezy west winds will develop this afternoon then diminish this evening. && .PRELIMINARY POINT TEMPS/POPS... GTF 44 70 48 68 / 0 10 30 10 CTB 41 70 45 69 / 0 10 10 0 HLN 45 72 48 73 / 0 10 10 10 BZN 41 72 43 71 / 0 0 20 10 WEY 31 64 34 66 / 10 0 10 0 DLN 42 70 43 72 / 0 0 0 0 HVR 44 72 46 71 / 20 0 20 10 LWT 42 67 45 65 / 10 10 50 20 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$ http://www.weather.gov/greatfalls