Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 210220 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 1020 PM EDT Sat May 20 2017 .SYNOPSIS... A farm front will drift slowly the north overnight. A cold front crosses from the west Sunday night. High pressure crosses Monday night, then low pressure for much of rest of work week. && .NEAR TERM /THROUGH SUNDAY/... As of 1020 PM Saturday... With convection in eastern Kentucky, and a long duration of rounds of showers and thunderstorms starting early Sunday and going well into Sunday night, opted to not let flash flood watch expire, and continued through Sunday night. Later shifts can determine if the flood watch needs expanded, but the current watch largely covers the intersection of lowest flash flood guidance and highest forecast rainfall amounts. The eastern kentucky convection was the result of late day recovery for the second straight day, along with a theta-e axis along a warm front, and outflow boundaries. As of 840 PM Saturday... A rather active evening of convection roughly along a theta-e axis along a warm front over the area was winding down with loss of heating. After a brief lull overnight, bands of convection along outflow boundaries and, eventually a cold front, will arrive from the west. The initial line of convection upstream will also weaken with the loss of heating. This could stiff arm arrival on our western flank until 09Z or so, if it dissipated altogether, but have chance pops well east after 06Z. Even a late arrival could create an 18-hour window of rounds of showers and thunderstorms, until the cold front finally crosses early Monday morning. The flood watch will expire at 10 PM, but will have to watch the potential for excessive rainfall Sunday through Sunday night. As of 305 PM Saturday... Frontal boundary will lift northward this afternoon and evening. With a moist airmass in place with afternoon heating will fire convection just about anywhere over the area. With weak flow aloft these storms will be slow movers. Any one of these storms could product upwards of an inch or two. With the saturated ground across the Southern Coalfields, went ahead an issued FFA for that area. Cold front to our west will continue to move eastward overnight and should be on our doorstep by 12z Sunday. Increased pops as front approaches. Generally went with a blend of guid for temps through out. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... As of 305 PM Saturday... Cold front pushes through Sunday night and exits early Monday morning. Pwats increase with limited sfc CAPE and deep layered shear. Therefore, expect an environment conducive to flash flooding and not severe for Sunday. WPC has most of WV under a Slight risk for excessive rainfall Sunday. A flash flood watch may be required. Behind the front, expect a period of cooler and drier air early Monday into Tuesday. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 305 PM Saturday... The chances for rain return by midweek with the next frontal system. Temperatures will return to a more seasonable level during this period. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... As of 840 PM Saturday... Showers and thunderstorms impacting an area mainly from CRW to EKN for few hours of forecast should dissipate with the loss of heating 02-03Z. Fog may start to form in the valleys in this area overnight on account of the rain, and back through the HTS area again, on account of the rain earlier there. Otherwise a cold front is expected to bring a long window of showers and thunderstorms all day Sunday, arriving as far east of the Ohio River before dawn, and lasting well into Sunday night. MVFR conditions will be common Sunday, with IFR possible in heavier rain. Light and variable winds will become south to southeast by Sunday morning, and be gusty on the ridges. Light to moderate south to southeast flow aloft will become moderate south to southwest overnight, and then light west to southwest Sunday afternoon. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY... FORECAST CONFIDENCE: Medium ALTERNATE SCENARIOS: Timing and placement of showers and thunderstorms early tonight may vary. Also, development and placement of fog may vary overnight. Conditions will vary in showers and thunderstorms on Sunday. 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 05/21/17 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 M HTS CONSISTENCY H H H H H H H H M L L L BKW CONSISTENCY M M M M M M M M M M M L EKN CONSISTENCY H H H M L M M M H H H M PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY H H H H H H H H H H H M AFTER 00Z MONDAY... IFR possible in showers and thunderstorms Sunday night, fog and stratus late overnight Sunday night into Monday, and in fog overnight Monday night into Tuesday morning.. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Flash Flood Watch through late Sunday night for WVZ005-013- 024>026-033-034-515-516. OH...None. KY...Flash Flood Watch through late Sunday night for KYZ105. VA...Flash Flood Watch through late Sunday night for VAZ003-004. && $$ SYNOPSIS...TRM NEAR TERM...JS/TRM SHORT TERM...JS/JW LONG TERM...JS/JW AVIATION...TRM is the U.S. government's official web portal to all federal, state and local government web resources and services.