312 FXUS61 KRLX 252014 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 414 PM EDT Fri Sep 25 2020 .SYNOPSIS... High pressure this weekend, followed by a strong cold front early next week. && .NEAR TERM /THROUGH SATURDAY/... As of 412 PM Friday... Speeded up the exodus of light pcpn east of our mountains during the late afternoon hours per latest radar imagery. Rest of forecast remains on track. As of 215 PM Friday... Upper trof axis pulls east this evening taking the steady rain that has affected southeastern WV and southwester VA with it. Dry air in the mid and upper levels will quickly advect into the region in the wake of departing system. However, an abundance of low level moisture will linger overnight even as surface high pressure builds overhead with patchy drizzle possible across the eastern slopes in the mountains. This will also allow for low stratus and areas of dense river valley fog to develop, following the initial clearing early this evening. I suspect the extent of dense fog expected will eventually warrant an SPS this evening or overnight, if not a dense fog advisory, especially across northeast KY and southeast OH. Low stratus and fog will be especially slow to lift and dissipate Saturday as inversion lingers. Eventually enough mixing and warming occur to weaken the inversion for sunshine to gradually make a return. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 230 PM Friday... Brief warming in the short term in ridging aloft, ahead of a filling upper low in the southern stream that will be pushing northeastward. This feature will become weaker as it moves into the area, with only a slight increase in moisture. Forecast will be conservative on the POPs, but might need to consider low end mountain chances for showers Sunday and Sunday night in future forecasts. Upper trough digs into the midwest, and southwesterly flow becomes more active, necessitating POP increases for the beginning of the work week ahead of the cold front. Temperatures above normal in lowland 80s for Sunday and Monday. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 230 PM Friday... Stout cold front plows through in the Monday night/Tuesday time frame. Details still coming together on the evolution of the broad upper level trough that will become dominant over the eastern CONUS, but showers can be expected with the front as well as a significant drop in the 850mb temperatures and 1000-500mb thicknesses. May see an upper low split from the main flow in its push southward, and then merge once again as the main trough amplifies. There may be a secondary cold front as a result reinforcing the cooler airmass near the end of the long term period. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... As of 220 PM Friday... System departs this evening taking the rainfall with it. In its wake, low stratus and areas of dense river valley fog will develop. This will impact all terminals with IFR, quickly dropping to VLIFR VSBY/CIGS by 06Z, if not sooner at some terminals. Conditions will be slow to improve Saturday...taking until late morning to lift out of IFR with MVFR BKN stratus likely lingering into early afternoon. Surface flow will generally be light and variable throughout. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY... FORECAST CONFIDENCE: High. ALTERNATE SCENARIOS: Timing onset and dissipation of low stratus/dense fog may vary an hour or two from forecast. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H H H M HTS CONSISTENCY L L M H H H H H H H H M BKW CONSISTENCY H H H H H H H H H H H M EKN CONSISTENCY H H H H H H H H H L H L PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H L AFTER 18Z SATURDAY... IFR conditions will be possible Sunday morning in dense river valley fog. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...26/30 NEAR TERM...ARJ/30 SHORT TERM...26 LONG TERM...26 AVIATION...30