Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 200138 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 938 PM EDT Sat May 19 2018 .SYNOPSIS... Upper system exits tonight. Weak disturbances cross early next week. Cold front crosses mid week, followed by high pressure to end the work week. Unsettled to start the Memorial Day weekend. && .NEAR TERM /THROUGH SUNDAY/...
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As of 935 PM Saturday... Went faster putting an end to pcpn from west to east this evening. Adjusted PoPs, and winds using the latest radar images and sfc obs. The rest of forecast remains on track. As of 1245 PM Saturday... Upper trough will swing through the CWA this evening, with increasing chances for showers and thunderstorms as it does so. Still overall expecting a low chance for anything to become severe, with overall lack of significant wind shear and strong dynamics, but will continue to highlight the potential in the HWO with SPC placing much of the CWA in a marginal risk for today. There are some breaks in the clouds noted on satellite, which of course will aid in thunderstorm development. Any storms that do develop will be capable of brief heavy downpours, with the anomalously high PW air mass in place. However, storms should overall move well, so widespread flooding risk is not expected, but could see issues in low lying spots/poor drainage areas. Trough pushes to the east of the CWA late tonight. Much of the area will start out quite cloudy on Sunday, particularly across northern/eastern zones where low stratus is expected to develop. Some clearing possible towards morning across extreme western zones. Otherwise, weather on Sunday looks to be drier, with a more stable pattern setting up, but can`t completely rule out a pop up shower or storm, so maintained the slight chance during the afternoon hours. Models hinting at the possibility of increasingly unsettled weather late Sunday night, into the short term period.
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&& .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... As of 335 PM Saturday... NAM12 and HIRESWnmm develop a convective complex over southwest Ohio Sunday afternoon, in response to a low level jet max and moisture feed out of the SSW, intersecting with a west to east oriented front sagging down from the north, possibly enhanced by an outflow boundary from upstream convection tonight. They then prog this complex to move ESEWD across the forecast area Sunday night, with rainfall totals up to two inches from the NAM12, and a much more confined axis of up to 1.5 inches off the HIRESWnmm. HIRESWarw shows this to a lesser extent, and faster, more of a late day event than a nocturnal one. Other models are not so bullish on this scenario, but show smaller pockets of convection to the south, and to the north, and central guidance reflects the smoothing resulting from a blended solution. The details of the forecast remain fuzzy through Tuesday, beneath zonal upper level flow, with the surface boundary remaining north of the area. Ripples in the zonal flow, and left over outflow boundaries will focus convection, which will be diurnally enhanced during the afternoon and evening hours. A cold front is forecast to cross or at least approach Tuesday night, from northwest to southeast, but most of the forcing and the better bulk shear is is progged to pass north of the forecast area, and the day 3 SPC marginal outlook for severe looks good. Above normal temperatures continue. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 335 PM Saturday... Models continue to differ on the timing of a cold front crossing Tuesday night into Wednesday, and central guidance reflects this with the chance for showers and thunderstorms south on Wednesday. Models do concur on dry weather Thursday and Friday, with high pressure beneath upper level ridging. A mid stream short wave trough approaching from the northwest, a southern stream low approaching from the south, and low level southerly flow of increasingly warm and moist air, will all conspire to bring unsettled weather back into the area in time for the start of the Memorial Day weekend. Temperatures remain above normal in the wake of the cold front. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... As of 745 PM Saturday... Radar images show lines of convection moving across the area northeast. These lines of showers and thunderstorms are producing brief periods of IFR conditions along their path. PWATS are around 1.7 inches tonight. This could produce localized downpours and IFR/LIFR conditions. Convection should decrease in coverage after 03Z, however, widespread MVFR cigs are expected to develop, particularly across the mountains and across areas that received rainfall. Southwesterly winds, with occasional gusts 15-20kts through 03Z. Gradual improvement to VFR after 15Z Sunday. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY... FORECAST CONFIDENCE: Medium ALTERNATE SCENARIOS: Development and extent of low stratus or fog overnight may vary 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. DATE SUN 05/20/18 UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 CRW CONSISTENCY H H H H H H H H H H H L HTS CONSISTENCY H H H H H H H H H H H L BKW CONSISTENCY H H H H H H H H H H H L EKN CONSISTENCY M H H L H M M M H H H L PKB CONSISTENCY H H H H H H H H M M M L CKB CONSISTENCY H H H H H H H M M H M M AFTER 00Z MONDAY... Brief periods of IFR possible in showers and storms into the beginning of the work week. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/SL NEAR TERM...ARJ/SL SHORT TERM...TRM LONG TERM...TRM AVIATION...ARJ

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