Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 200725 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 325 AM EDT Sun Aug 20 2017 .SYNOPSIS... High pressure Sunday through Tuesday. Strong cold front late Tuesday/Tuesday night. Cooler and drier for the end of the week. && .NEAR TERM /THROUGH TONIGHT/...
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As of 255 AM Sunday... Weakening east to west surface boundary across southeast OH and central WV at 06Z will dissipate Sunday morning as weak high pressure takes over. Isolated convection continues to diminish overnight as drier air aloft spreads over the area, and should be gone before dawn. However, mostly clear skies and calm winds early this morning will lead to some dense valley fog, especially where it rained earlier. Fog will burn off shortly after dawn, leaving abundant sunshine under the weak high pressure for Sunday. The high pressure center itself shifts just far enough east this afternoon to turn low level winds to a southwesterly component, but with a more southerly component east of the mountains. This will lead to modest low level convergent flow east of our mountain ridges with modest pooling of low level moisture. However, it looks like models keep this zone just east of our forecast area, so that any isolated afternoon convection is expected to stay just east of our mountain counties over western VA. So, no pops in the forecast today. It will be very warm and just a bit more humid with a slight increase in low level moisture, with highs near 90 degrees under abundant sunshine. Tonight looks to be tranquil and mild as the weak high pressure system still controls our weather.
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&& .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 230 AM Sunday... Accounting for the eclipse in the temperature grids on Monday afternoon by using modest hourly temperature reductions from 18-20Z given the sky cover in the 20-35 percent range. Digging trough aloft into the Great Lakes will drive an airmass changing cold front late Tuesday and Tuesday night, with increasing flow out ahead of the system. Better dynamics will be further northeast of the area, but thunderstorms are possible upon entrance into the CWA late Tuesday, but will erode as the front moves through in the late evening/overnight time frame. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 230 AM Sunday... Should run 10-15 degrees cooler in both temperature and dewpoint in the wake of the front as Canadian high pressure brings pressure rises back into the middle Ohio Valley and central Appalachians. The western CONUS ridge/eastern CONUS trough setup will persist, with high pressure holding through the weekend. The long term will be largely dry, with temperatures very gradually ticking upwards. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... 06Z Sunday thru 06Z Monday... As of 145 AM Sunday... A weakening east to west surface boundary across southeast Ohio and central WV will continue to weaken overnight, and dissipate Sunday morning. Isolated convection along this boundary will gradually dissipate by Sunday morning. Thru 12Z Sunday... SCT-BKN clouds 4000-6000 feet AGL along aforementioned surface boundary with an isolated shower. River valley fog between 07Z and 12Z, especially in areas that received rain earlier. Expect PKB, EKN and CRW to be the most prone for IFR fog. Light south to calm valley winds. After 12Z Sunday... Fog burns off by 13Z, then VFR conditions can be expected with mainly SCT clouds 4000-6000 feet AGL. Will keep mention of any showers out of WV mountains for now. Winds becoming west to southwest 3 to 8 KTS by afternoon. After 00Z Monday...VFR mostly clear. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY... FORECAST CONFIDENCE: High, except low to medium with fog. ALTERNATE SCENARIOS: Timing, density, and location of fog overnight could vary. 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 08/20/17 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 CRW CONSISTENCY H H M M L L L M H H H M HTS CONSISTENCY H H M M L L L M H H H M BKW CONSISTENCY H H M M M M M M H H H M EKN CONSISTENCY M L L L L L L M H H H M PKB CONSISTENCY H M M M M L L M H H H M CKB CONSISTENCY H H M M L L L M H H H M AFTER 06Z MONDAY... Dense river valley fog possible each morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...JMV/26 NEAR TERM...JMV SHORT TERM...26 LONG TERM...26 AVIATION...JMV is the U.S. government's official web portal to all federal, state and local government web resources and services.