Area Forecast Discussion
Issued by NWS Charleston, WV

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883 FXUS61 KRLX 190900 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 400 AM EST Sun Nov 19 2017 .SYNOPSIS... Much colder air arrives first thing this morning. High pressure Monday through Tuesday. Cold front crosses Tuesday night. High pressure again through Thanksgiving. Cold front crosses Saturday. && .NEAR TERM /THROUGH TONIGHT/... As of 240 AM Sunday... Cold frontal boundary to the east of the CWA, with -shra and gusty winds continuing behind the front. Behind the front, colder air filtering into the region, and expecting temperatures to fall throughout the morning and possibly early afternoon, before holding somewhat steady. The gusty winds will continue for most of the day with tight pressure gradient and caa occurring. As the colder air filters in, any lingering rain showers will gradually change over to either a mix or light upslope snow showers across the northern mountains. There still looks to be an uptick in the precipitation later this afternoon and evening, as a series of upper disturbances move across the north. This will lead to an increasing chance of accumulating snows across the mountains, with a rain/snow mix expected across much of southeast Ohio and northern WV zones, before transitioning to all snow overnight. Still looking at little to no snow accumulation across the northern WV lowland counties, with a general 1 to 4 inches across Randolph, Webster, and Pocahontas counties, with the higher amounts in favored upslope areas. Will continue the WSY across the higher terrain of these counties. Snow will gradually taper off towards morning as high pressure builds into the region from the west, and flow becomes less favorable. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... As of 240 AM Sunday... High pressure passes south of the area Monday, and then moves east, as upper level flow backs. This results in deep layer southwest flow Tuesday, and hence milder weather. A cold front reverses this trend, as it slips through Tuesday night into early Wednesday morning. The associated upper level short wave trough passes north of the area, leaving the area on the anticyclonic shear side of the jet stream. This, along with little inflow ahead of the front, spells little precipitation associated with this front. Continued the slight chance in the mountains for Tuesday night. High pressure builds in Wednesday and Wednesday night, bringing a return to the dry, chilly weather, although clouds associated with another upper level short wave trough approaching from the west, and low pressure passing south of the area, will limit radiative cooling somewhat Wednesday night. No deviations needed from central guidance temperatures, other than to lower a bit Monday morning. && .LONG TERM /THURSDAY THROUGH SATURDAY/... As of 240 AM Sunday... High pressure will dominate Thursday through friday, with more dry, chilly weather, even as an upper level short wave trough crosses. A stronger short wave trough deepens as it crosses the area Saturday, driving a cold front through. Despite the amplification of the trough, only the small chance for light precipitation is forecast for Saturday into Saturday night, with little inflow ahead of the front Saturday. Models continue in good agreement on this system, with faster timing compared with the previous forecast. No changes were needed to central guidance temperatures and dew points, which trended lower at the end, but still a little above deterministic guidance. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... As of 1245 AM Sunday... 06Z Sunday through 06Z Monday... Widespread MVFR conditions across the area, with winds gradually shifting to a more westerly/northwesterly direction behind a cold front, which at 06Z is entering mountainous areas. Along the front, brief wind gusts of 40 to 50 mph are possible, along with moderate to heavy rain showers, creating restrictions. Front will exit to the east of the mountains around 08Z, with gusty westerly/northwesterly winds continuing, with gusts in the 20 to 30 kt range across the lowlands, and the 30 to 40 kt range across the higher terrain. After 18-21Z on Sunday, some general improvement from west to east to VFR as surface high pressure builds into the region. Bulk of gustier winds will generally drop off after 22Z, but will continue across the higher terrain and parts of northern WV for the remainder of the TAF period. Rain will change to snow in the mountainous counties late tonight or during the day Sunday. Expect widespread MVFR and local IFR conditions in snow. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY... FORECAST CONFIDENCE: Medium ALTERNATE SCENARIOS: Timing of improvement to VFR on Sunday could vary from forecast. Conditions could be worse in mountainous counties than currently forecast, particularly in snow showers. 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 11/19/17 UTC 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20 EST 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15 CRW CONSISTENCY H M H H H H H H M M M L HTS CONSISTENCY H H M M M M H H H M H L BKW CONSISTENCY L H H L H H M M M M M L EKN CONSISTENCY M L L L M L L L L M L L PKB CONSISTENCY H H M M H H H M H H M L CKB CONSISTENCY H H H H H H H M H L L L AFTER 06Z MONDAY... Isolated IFR possible in upslope snow showers across mainly the northern mountain counties into early Monday morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Wind Advisory until noon EST today for WVZ520-522>524-526. Wind Advisory until 10 AM EST this morning for WVZ032-039-040- 521-525. Winter Weather Advisory until 3 AM EST Monday for WVZ522-523- 526. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/SL NEAR TERM...SL SHORT TERM...TRM LONG TERM...TRM AVIATION...SL is the U.S. government's official web portal to all federal, state and local government web resources and services.