Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 181311 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 911 AM EDT Fri Aug 18 2017 .SYNOPSIS... Cold front today. Upper trough Saturday. High pressure through Tuesday. Strong cold front mid week. && .NEAR TERM /THROUGH TONIGHT/...
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As of 910 AM Friday...Updated PoP and Sky cover based on current Radar, satellite and mesomodel trends. Decided to clear clouds out faster from west to east this afternoon with lingering clouds and showers in the mountains into this evening. As of 633 AM Friday... No significant changes. As of 255 AM Friday... Even though we have a significant upper trough crossing the Ohio Valley with a cold front today, timing of the front along with the strength and axis of QPF with this system is not that easy. First, this is still summer, so trying to time the cold front with the upper trough will be difficult, and models do have a good piece of its main energy lifting up across Ohio and Pennsylvania. Will adjust frontal movement a bit faster than the models today, aided by mixing with stronger west winds aloft with diurnal heating. Given this scenario, timing would have the front along the Ohio River around noon, central WV around 3 PM, and exiting the mountains early this evening. Convergence along the front is not impressive to be the main focus of activity. On the other hand, it looks like a well defined upper disturbance within this upper trough ahead of the front over south central KY will be the main focus for convection today, as it lifts northeast across our area. With PW`s above 2 inches and the atmosphere conditionally unstable, it wont take much to fire off convection. Indeed, models do paint significant convection, especially northwest two thirds of the area, with this upper feature. Some of the storms will have locally heavy rain, but no significant water problems or severe thunderstorms are expected today. So, we have pops starting out high along the Ohio River early this morning, then shifting east northeast across the area today. Note that much of southeast Ohio will escape convection with this feature, having already been affected by another disturbance last evening. Most of the convection will be over eastern WV by mid afternoon, but will still carry a small pop until the front passes. In any case, convection will exit the mountains this evening as drier high pressure and clearing skies move in for tonight. So we may have to evaluate for a good river valley fog later Friday night. Temperatures will be tempered today with the clouds and showers, but will be humid ahead of the front. Cooler tonight with the clearing and drier air.
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&& .SHORT TERM /SATURDAY 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 /13Z FRIDAY THROUGH TUESDAY/...
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12Z Friday thru 12Z Saturday... As of 633 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. Outside of convection, look for VFR ceilings. lowering to MVFR ceilings/vsby in convection, but IFR in the heaviest convection in the main band. Also IFR ceilings for about a 2 hour period in the west this morning following the main band of convection. Behind the front, becoming SCT-BKN 4000-6000 feet AGL. With drier high pressure building in, look for clearing from west to east this afternoon into this evening. With mostly clear skies setting in tonight, river valley IFR 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 to near calm tonight. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SATURDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing and coverage of showers and thunderstorms 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. UTC 1HRLY 12 13 14 15 16 17 18 19 20 21 22 23 EDT 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 CRW CONSISTENCY M M L H M H H H H H H M HTS CONSISTENCY L L H M H H H H H H H M BKW CONSISTENCY H H H H H M H H H H H M EKN CONSISTENCY H H H M L M H H H H H M PKB CONSISTENCY L M H M L H H H H H H M CKB CONSISTENCY L L M M H L H H H H H M AFTER 12Z SATURDAY... Dense river valley fog possible each morning.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...JMV/26 NEAR TERM...JMV/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.