Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 270732 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 332 AM EDT Thu Jul 27 2017 .SYNOPSIS... Low pressure system brings rounds of showers and thunderstorms, with heavy rain through Friday. High pressure with cooler and less humid air follows for the weekend into next week. && .NEAR TERM /THROUGH TONIGHT/... As of 300 AM Thursday... A cold front will slowly sink southeast across the Ohio River valley through tonight. This will increase the threat of showers and thunderstorms, particularly from afternoon on. Meanwhile, the atmosphere will rapidly moisten with precipitable water values quickly approaching 2 inches by this afternoon. Currently, the HRRR has a decent handle on the convection moving into Indiana. The trend will be weaker over the next several hours transitioning to a broken line of showers as it approaches the western part of the forecast area by mid-morning. From there, diurnal heating should help this increase in coverage and intensity as it pushes across West Virginia this afternoon. From there, it will depend on the timing and placement of weak waves of low pressure that develop and move along the frontal boundary to assist in shower and thunderstorm development. Overall, there doesn`t seem to be a whole lot of instability and available energy. This may limit the high end potential of storm strength and coverage. So, while I do expect most areas to see showers and thunderstorms, I do not expect any specific location to continually be impacted today. Better coverage may wait until later tonight or Friday as the surface cold front approaches to provide more widespread lift. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... As of 315 PM Wednesday... Models in general agreement with the overall progression of the cold front pushing through the area with sfc pressure riding up along it, then exits Saturday morning with the aid of a very progressive upper level low rotating through. Main concern where heaviest axis of rain sets up. Models still differ on exact placement through the period and will hold off on any FFA possibilities for now. Will still keep the mention of heavy rain potential in the HWO for Friday. A cool and dry high pressure system will build in behind the front later Saturday and Saturday night. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 335 PM Wednesday... A cool and dry period is on tap as cool Canadian high pressure will be in control for much of the work week. There will be a slow increase in high temperatures each day, but it will be dry with temperatures at or below normal. && .AVIATION /07Z THURSDAY THROUGH MONDAY/... As of 300 AM Thursday... Fog early this morning should be limited to the valleys of northeastern West Virginia, as a low pressure system approaching from the west brings increasing clouds. Have IFR only in the Tygart Valley and MVFR mist for CKB, PKB and possibly CRW /6SM coded there/. The likelihood for showers and thunderstorms increases as the day progresses today. Clouds and the near widespread coverage of the showers and thunderstorms limits the severe risk, but thunderstorms could still produce strong wind gusts, and any thunderstorm can bring IFR conditions in heavy downpours. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY... FORECAST CONFIDENCE: Medium to high. ALTERNATE SCENARIOS: Formation and timing and dissipation of fog could vary early this morning. Timing of showers and thunderstorms, and associated flight categories, could vary later today and tonight, with short term amendments likely needed. 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 THU 07/27/17 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 H H H H H H H H H M HTS CONSISTENCY H H H 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 M M L L L L M M H H H M PKB CONSISTENCY M M M M M L M H H H H M CKB CONSISTENCY H H H M M H H H H H H M AFTER 06Z FRIDAY... Brief periods of IFR conditions with thunderstorms likely tonight into Friday, perhaps more persistent in low clouds Friday morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...JS/99 NEAR TERM...99 SHORT TERM...JS LONG TERM...JS AVIATION...TRM/99 is the U.S. government's official web portal to all federal, state and local government web resources and services.