281 FXUS65 KRIW 071738 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 1038 AM MST Sun Nov 7 2021 .SHORT TERM...(Today through Monday) Issued at 310 AM MST Sun Nov 7 2021 Strong southwesterly flow aloft is currently bringing abundant mid- level moisture to the region. As this moisture is forced over the high terrain, abundant orographic snowfall is occurring, with snow levels around 6500 to 7000 ft. A Winter Weather Advisory remains in effect for Yellowstone National Park through the morning hours, as a few more inches of snow are possible there before the jet stream shifts southward and begins to force snow showers over mountain ranges further south (such as the southern Absaroka, Salt, Wyoming, and Wind River Mountains). No highlights are planned as the intensity of moisture transport will wane throughout the day. Nevertheless, those traveling over mountain passes in western Wyoming will want to plan for winter driving conditions as a light accumulations are likely for the higher elevation roads. Temperatures today will be 5 to 10 degrees cooler than those experienced Saturday, as cooler air pushes in from the north. Those in the Bighorn and Powder River Basins will note a shift to northerly winds mid-day as a weak cold front ushers in a cooler air mass. Winds will again be breezy this afternoon for those in the wind corridor from Rock Springs to Casper, but not as windy as yesterday. Increased mid-level cloud cover and light precipitation is possible for basins overnight into Monday, but rain/snow accumulations will be minimal. Snow levels are forecast to be in the 6000 to 6500 where precipitation is occurring. The atmosphere dries out Monday afternoon, leaving only isolated lingering showers. Monday's highs will be another 5 degrees cooler than Sunday, which leaves them close to seasonal averages. .LONG TERM...(Tuesday through Saturday) Issued at 310 AM MST Sun Nov 7 2021 Tuesday will feature a lull in activity as the forecast area will be sandwiched between two systems. A brief ridge will build into the area Tuesday morning and rapidly break down through the day as southwesterly flow ahead of the next system moves overhead. A subtle shortwave will move into the western mountains Tuesday afternoon bringing increased PoP. East of the Divide will remain dry for the time being but increased surface winds can be expected in the wind prone areas. Presently surface winds look to be below High Wind Warning criteria, but highlights could eventually be needed for portions of Natrona, Fremont and Sweetwater counties. Widespread precipitation expands east of the Divide late Tuesday night as a front moves through the area. Timing and temperatures look to be favorable for snow in the eastern areas. Mountain snow will continue overnight. Widespread PoP continues through the day Wednesday before the system exits late Wednesday night. Temperatures look to increase through the day Wednesday favoring a shift to rain before tapering off. Presently snow accumulations look to be on the lighter side for the eastern areas due to relatively warm temperatures. However, the finer details are still uncertain. Potent northwesterly flow develops post-front Thursday into Friday. This will keep the snow machine going in the western mountains into the weekend. Models remain in agreement into next weekend with upper-level ridging drying the region out after an active week. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) Issued at 1036 AM MST Sun Nov 7 2021 Precipitation continues to end this afternoon across the west, and as a result, all sites should remain VFR through the period. KJAC could see occasional MVFR ceilings through 21Z this afternoon as some low clouds could stream across the site briefly at times as the showers end. Mountain obscurations will continue through 09Z Monday across the far west. KBPI and KPNA could see some showers or late tonight before showers completely end by Monday morning. Gusty winds across KCPR and KRIW will continue this afternoon. KCPR could see breezy winds gusting 20 to 25 kt this afternoon while KRIW should not see gusts over 20kts. Winds will diminish by sunset. && .FIRE WEATHER... Issued AT 310 AM MST Sun Nov 7 2021 Temperatures today will be about 5 to 8 degrees below readings seen yesterday. Winds are again breezy this afternoon for the mid-slopes and those in the wind corridor from Rock Springs to Casper, but not as windy as yesterday. Mountain ranges continue to see snow today into tonight, with snow levels around 6500 ft. Precipitation will be light for basins and valleys, with only trace accumulations today through Monday afternoon. Active weather continues through the week with breezy afternoon. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...VandenBoogart LONG TERM...Vorst AVIATION...Hensley FIRE WEATHER...VandenBoogart