Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 180649 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 249 AM EDT Fri Aug 18 2017 .SYNOPSIS... Cold front Friday. Upper trough Saturday. High pressure through Tuesday. Strong cold front mid week. && .NEAR TERM /THROUGH TODAY/... As of 840 PM Thursday... Updated the forecast to better handle the showers/thunderstorms moving across northern WV this evening. As of 540 PM Thursday... Line of thunderstorms is moving into western portions of the area faster than models indicated. Have updated the forcast for early this evening to reflect this faster timing. As of 225 PM Thursday... QLCS across Eastern Ohio associated with a prefrontal trough will push into the Ohio Valley later this evening. Well out ahead of this line we are currently seeing isolated to scattered showers and storms across our area. Despite moist and unstable low level profiles, drier air in the mid level has kept these cells in check, and the severe threat with these cells is extremely low, however they do contain brief downpours. Any severe storm threat will be associated with the main convective line later this evening, but this threat is still quite low, with our Northern Ohio Counties most at risk. Here, 0-6km bulk shear will be strongest at about 30 to 35 knots and although instability will drops off by the time it arrives later this evening, there may still be enough there to produce borderline severe storms. Also, with the high PWATs, torrential rainfall will be possible into the overnight hours. The actual cold front will not pass the area until later tomorrow afternoon and some weak showers and storms are possible. Behind the front drier air moves in with high pressure. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... As of 240 AM Friday... Upper level trough brings another batch of showers/storms through primarily the northern half of the forecast area Saturday before the long wave pattern goes back to ridge dominant over the southeastern US. This ridge will bring higher heights over the region, with temperatures back into the upper 80s to lower 90s for the lowlands through the weekend and into the beginning of next week. Expecting mainly dry weather after Saturday && .LONG TERM /TUESDAY THROUGH THURSDAY/... As of 240 AM Friday... Long term operational models showing some consistency in the development of a closed low over the Canadian prairies that will drop into the Great Lakes for the middle of next week. Associated cold front will bring the Ohio Valley and central Appalachians back into a cooler and drier airmass in a more amplified ridge/trough pattern from west to east across the CONUS. CPC outlook is supportive of the operational model solutions as of this point with chances for below normal temps embedded in the northeast quadrant of the lower 48. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... 06Z Friday thru 06Z Saturday... As of 145 AM Friday... An upper disturbance and cold front will move east across the area today, bringing showers and TSTMS. Most of the convection will be in an organized band ahead of the front itself with the upper disturbance, lasting about a 3 to 4 hour period in any location. The front will lag behind this band, so continue scattered convection until the front actually passes. The front will likely reach the Ohio River around 16Z, a CKB-CRW line around 20Z, and exiting the mountains around 00Z. Fog early this morning will be limited mostly to the protected valleys of the mountains, affecting EKN til around 10Z when the clouds move in. Outside of convection, look for VFR ceilings, lowering to MVFR ceilings/vsby in convection, but locally IFR in the heaviest convection in the main band. Behind the front, becoming SCT-BKN 4000-6000 feet AGL thru the afternoon. With loss of heating and high pressure building in, look for rapid clearing from west to east early this evening. With mostly clear skies setting in tonight, fog appears likely after 06Z Saturday at the major TAF sites. Generally south to southwest winds 5 to 10 KTS ahead of the front today, becoming westerly at the same speeds behind the front, then light and variable tonight. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing and coverage of showers and thunderstorms could vary. Some fog can not be ruled out in the mountain valleys early this morning. 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 FRI 08/18/17 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 M M L HTS CONSISTENCY H H M M H M H M H L L L BKW CONSISTENCY H H H H H H H H H L H L EKN CONSISTENCY H H H L M M M L H M M L PKB CONSISTENCY M M M L M M M M M H H L CKB CONSISTENCY M H H H H H M H H M M L AFTER 06Z SATURDAY... Dense river valley fog possible each morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...JMV/26 NEAR TERM...RPY/MPK 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.