200 FXUS61 KRLX 161041 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 641 AM EDT Sun Oct 16 2022 .SYNOPSIS... Showers/thunderstorms spread across the south this afternoon. Cold front tonight ushers in the coldest air of the season so far for the early portion of the work week. && .NEAR TERM /THROUGH TONIGHT/... As of 640 AM Sunday... Forecast on track, with mid level cloud increasing across the area in response to cold front approaching from the northwest, and flat wave approaching from the southwest. As of 220 AM Sunday... High pressure exits early this morning, giving way to a mid level flat wave approaching from the southwest, and an initially dry cold front approaching from the northwest. Moisture increases on low to mid level west to southwest flow today, which still remains a bit strong ahead of the flat wave. Now nearer the event, central guidance PoPs have tightened the probability of rain gradient across central portions of the area, with rain showers moving into southeast portions of the forecast area early this afternoon, and then shifting off to the east overnight tonight, as the wave exits. However, showers may develop over the northern mountains overnight tonight, as the cold front crosses, and upslope west to northwest flow develops in its wake. Southeast portions of the area will also be in an overlap of the southwestern extent of bulk shear and the northeastern extent of surface based instability. The strong flow atop the deep mixing layer backing and slackening off beneath may be enough for strong thunderstorm wind gusts, prompting SPC to upgrade to a marginal risk for severe thunderstorm wind gusts across southeastern portions of the area, about as far north and west as a Williamson to Beckley line. With the clouds and rain across southeast portions of the area today, central guidance has flattened the northwest to southeast temperature gradient seen across the area Saturday as a cold front crossed, but still a bit above normal overall. The cold front starts to re-establish the gradient tonight, with lows straddling normals across the gradient. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... As of 230 AM Sunday... Area will begin to dry out on Monday as quick moving disturbance to the south gradually pushes off to the east. Much cooler air will then filter into the region on Monday as frontal boundary pushes east of CWA, and upper trough/low over Great Lakes region gradually starts to deepen across the CWA. Although temps on Monday won't be extremely cold, the cooler temperatures combined with gusty winds from tight pressure gradient and winds aloft mixing down to at least ridge tops, will be a bit of a shock to the system so to speak. In addition, with the cooler air gradually making its way into the area, widespread freezing temperatures are looking to be a good bet Tuesday morning, and expect a freeze watch to be issued on subsequent shifts. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 235 AM Sunday... Upper low/trough over Great Lakes will gradually deepen over the area, with a strong NWLY fetch setting up, transporting moisture from the Great Lakes into our CWA. This will create showers, mainly across the north and east, with light snow showers anticipated across the northern mountains. Some lowland locations could even see a few flakes at times, particularly in the overnight period Tuesday night into Wednesday. Expecting the potential for generally an inch or less of accumulation across the higher terrain of the northern mountains, with no accumulation expected elsewhere. Upper trough will eventually kick off to the east Wednesday into Thursday, with drier conditions, and milder conditions taking hold. The dry conditions linger for the remainder of the period, with the potential for a nice warm up by next weekend as southerly flow increases. && .AVIATION /10Z SUNDAY THROUGH THURSDAY/... As of 640 AM Sunday... River Valley fog, most notably along the Tygart Valley and Elk rivers, will dissipate by 14Z, with not much if any impact at CRW, but LIFR to start at EKN as implied by the ceiling there. AMD NOT SKED continued at EKN on account of the visibility outage there. Otherwise altocumulus ahead of a cold front approaching from the northwest, and a flat wave approaching from the southwest, will lower this afternoon across southern portions of the area, where rain showers are likely this afternoon and evening. These showers should, for the most part, stay south of HTS and CRW, where VCSH mention is continued. Showers are likely to impact BKW with MVFR conditions this afternoon into this evening, that are then likely to continue tonight, with a lingering stratocu deck, and possible mist, even as the rain ends. The ceiling at BKW may even lower to IFR overnight tonight. MVFR ceilings, and possible MVFR visibility in a rain shower or two, may impact CKB and EKN overnight tonight, as the cold front crosses there. Light south to southwest/variable surface flow early this morning will become light southwest today, except possibly a bit gusty up at PKB this afternoon. Light to moderate west to southwest flow aloft this period may strengthen a bit from the southwest across southern WV this afternoon, coincident with steep low level lapse rates associated with daytime heating. This could lead to thunderstorms there that could then bring down strong wind gusts this afternoon, even into this evening. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY... FORECAST CONFIDENCE: Medium to high. ALTERNATE SCENARIOS: A thunderstorm may impact BKW later this afternoon into this evening, with IFR or worse conditions, and possibly strong wind gusts. Extent of MVFR conditions overnight tonight may vary, especially in and near the mountains. 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. DATE SUN 10/16/22 UTC 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20 EDT 1HRLY 05 06 07 08 09 10 11 12 13 14 15 16 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY L L L L M H H H H H H H 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 H AFTER 12Z MONDAY... IFR possible in snow showers in the higher mountainous terrain Tuesday night into Wednesday. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Freeze Watch from Monday evening through Tuesday morning for WVZ005>011-013>020-024>031-033-034. OH...Freeze Watch from Monday evening through Tuesday morning for OHZ066-067-075-076-083>087. KY...Freeze Watch from Monday evening through Tuesday morning for KYZ101>103-105. VA...Freeze Watch from Monday evening through Tuesday morning for VAZ003-004. && $$ SYNOPSIS...TRM/SL NEAR TERM...TRM SHORT TERM...SL LONG TERM...SL AVIATION...TRM