Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 041954 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 254 PM EST Sun Dec 4 2016 .SYNOPSIS... Weak upper trough crosses this afternoon and tonight. A low pressure system crosses Monday night and Tuesday. Briefly milder in its wake mid week, then much colder late week. && .NEAR TERM /THROUGH TONIGHT/... As of 230 PM Sunday... Warm air advection aloft and weak isentropic lift is bringing light rain to Southwest Virginia this afternoon. The rain has been confined mostly to our south with just mid and upper level clouds currently across the forecast region. Fairly dry air in the low levels has mostly kept precip at bay and seeing just mid level clouds across much of the region for now. Low level southeast flow this afternoon and into the evening will likely produce upslope clouds and an isolated shower in the Eastern Mountains but not expecting widespread PoPs to enter the region until later this evening with approaching short wave. The weak shortwave moves through late tonight into tomorrow morning. Dewpoints are mostly in the mid to upper 20s and as precip moves in this drier air at the surface will likely allow for some evaporational cooling. Although confidence is still fairly low at this time, there is certainly still some potential for a wintry mix, including periods freezing rain overnight, mostly across the parts of Randolph and Pocahontas counties. Not expecting significant impacts, but a trace to a couple of hundredths of ice accumulation could make for slick travel. Have decided to leave current winter weather advisory as is for now. High pressure builds back in for a brief period tomorrow and conditions should improve late morning into the early afternoon. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... As of 420 AM Sunday... System pulls out first thing Monday morning. Low level westerly flow quickly takes out the CAD and, with a lack of cold air arriving in the wake of this system, temperatures climb quickly above freezing, and any lingering light precipitation Monday morning should be of the liquid variety. The next system, a closed upper level low over northwest Mexico this morning that loiters around there today before lifting out into TX tonight and Monday, opens up and dampens out as it lifts through the Ohio Valley Tuesday. This causes rain to rapidly overspread the area overnight Monday night, and then move through the area on Tuesday. With a stronger surface low pressure system compared with its predecessor, a stronger CAD wedge develops as the system approaches Monday night, and freezing rain is again possible on the higher eastern slopes and ridge lines of Pocahontas and Randolph counties. Warm advection should erode the CAD wedge on Tuesday. A bit of snow is possible over the higher terrain of the northern WV mountains on west to northwest upslope flow in the wake of the system Wednesday morning, but only slightly colder air moves in, as weak high pressure of Pacific origin approaches on Wednesday. Models continue to differ on weather the next cold front, a much stronger one, arrives Wednesday night. Temperatures close to guidance blends, which reflect a compromise that leans toward the lower side when models diverge Wednesday night. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 420 AM Sunday... A strong cold front crosses the area sometime Thursday. Models continue to differ on this, one factor being whether a wave forms along the front and slows it down. Per WPC and coordination with neighboring offices, the forecast continues to represent a compromise that leans toward the faster and colder side. This would have rain showers that mix with and change to snow showers in the west and over the higher terrain Thursday, followed by a transition to all snow showers as Thursday evening approaches. The cold air takes charge Thursday night, and remains in firm control into Saturday. This sets up the potential for frozen precipitation as the next weather system approaches Saturday night, which would then likely change to rain at least across much of the lowlands on Sunday given a track west of the area, at least initially. Temperatures close to a guidance blend, except leaning toward the lower side on Thursday. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... As of 1245 PM Sunday.... Mid to upper level clouds will lower this afternoon and evening as a weak system approaches from the west. Generally, VFR conditions should hold through about 00Z. Then more widespread rainfall arrives as well as MVFR conditions, with IFR conditions mostly in the mountains with southeasterly upslope flow. High pressure will start to build into the area Monday morning, but low level moisture could linger until Monday afternoon, especially in the mountains. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY... FORECAST CONFIDENCE: Medium to High. ALTERNATE SCENARIOS: Timing of precipitation and MVFR/IFR conditions tonight may vary. Ceilings may lift faster tomorrow morning than currently 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 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H H H L L L L M M M L HTS CONSISTENCY H H H H H M L H H H H L BKW CONSISTENCY H H M M M M H H L M M L EKN CONSISTENCY H H H H H H H H M L L L PKB CONSISTENCY H H H H H H L H H H H L CKB CONSISTENCY H H H H H H H H H M M L AFTER 18Z MONDAY... IFR possible in rain on Tuesday. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Winter Weather Advisory until 6 AM EST Monday for WVZ523-524- 526. OH...None. KY...None. VA...None. && $$ SYNOPSIS...MPK/26 NEAR TERM...MPK SHORT TERM...TRM LONG TERM...TRM AVIATION...MPK is the U.S. government's official web portal to all federal, state and local government web resources and services.