Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 060920 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 420 AM EST Tue Dec 6 2016 .SYNOPSIS... Low pressure crosses today and tonight, bringing freezing rain to very high terrain, and rain elsewhere. High pressure Wednesday. A cold front crosses early Thursday. Much colder into the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 420 AM Tuesday... Miller B type low pressure system crosses today, its primary center filling as it moves up the Ohio River Valley, giving way to a second center that tracks across the Carolinas to the east coast. Widespread rain moving into the area as a result early this morning will make for a wet day today. Models continue to paint a half inch to an inch of rain on average, with the highest amounts in the mountains, and west of the Ohio River, with the typical southeast downslope rain shadow resulting in the lower amounts over the WV lowlands. Cold air beneath frontal inversion will result in freezing rain across the very high terrain given the cold air damming wedge developing early this morning. Outside the radiation inversion northeast of the area, the air upstream (to the northeast) is not quite cold enough to support ice. However, upslope flow will result in sufficient cooling high along the eastern slopes for freezing rain across the very highest terrain. With the wedge developing this morning and then only gradually eroding later this afternoon, the 7 PM end time of the freezing rain advisory looks good, although the lower terrain within the advisory area may not experience much icing at all. The cold front moves through later tonight as the system pushes east, with the coastal low pressure center having taken over. This will finally take out the cold air damming wedge. However, colder air moving back in behind the system, coupled with the loss of all but low level moisture, may result in freezing rain or freezing drizzle, again across the very high terrain, early Wednesday morning. A blend of the NAM, MET and a short term consensus appeared to have the best handle on temperatures, a bit higher in the advisory area than the previous forecast. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... As of 420 AM Tuesday... Overall, brief break in the precipitation expected for Wednesday as high pressure briefly takes hold. Could still be some areas of -DZ early Wednesday morning behind departing low, but overall, expecting a drier, day, with some partial clearing in cloud cover. Precipitation will return to the area however by Thursday as a combination of an upper level trough, sags south into the area, allowing for colder air to infiltrate into the region, and favorable northwesterly flow to set up off the Great Lakes, allowing for some -shsn, and from a shortwave that will track northeast through the region early in the day Thursday. Expecting light snowfall accumulations, mainly across mountains in favored upslope regions, with little to no accumulations across the lowlands. In addition to the colder air/-shsn, expect breezy conditions on Thursday due to CAA. -shsn will continue on Friday, along with blustery conditions, as northwesterly flow remains in control. && .LONG TERM /SATURDAY THROUGH MONDAY/... As of 420 PM Tuesday... Milder air to take hold over the weekend as weak upper ridging builds in response to approaching sw trough/low pressure system, which will spread precipitation, mostly in the form of rain, except for across the higher terrain, back into the region by the end of the week, with a transition over to snow showers late Sunday night into Monday as the system departs and colder air infiltrates into the area. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... As of 100 AM Monday... A low pressure system crossing the area this period will bring MVFR to IFR conditions in rain. After a VFR overnight, the rain is expected to quickly overspread the area near dawn Tuesday. While a brief period of freezing rain is possible at EKN 12-14Z Tuesday, the best chance for freezing rain Tuesday morning will be east of there, along the higher eastern slopes of the mountians, and icing is possible aloft in that area below an inversion, which will be 3-4 kft MSL. The rain will exit Tuesday evening. Visibilities will improve, but low MVFR to IFR stratus will persist. Surface flow will be light east to northeast across the lowlands overnight and light southeast on Tuesday, and southeast and a bit gusty across the ridges overnight through Tuesday. Surface flow will shift to light west as the system exits Tuesday night. Light south flow aloft overnight will become moderate south to southeast Tuesday morning, and then moderate west to northwest as the system exits Tuesday night. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY... FORECAST CONFIDENCE: High becoming medium. ALTERNATE SCENARIOS: Timing of precipitation and associated MVFR to IFR conditions may 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. DATE TUE 12/06/16 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 M M L L L M M M M M M L HTS CONSISTENCY H H H M M M M H L H L L BKW CONSISTENCY H H H H H H H H H H H L EKN CONSISTENCY H H H H H M M M M M M L PKB CONSISTENCY H H H L L M M H H M M L CKB CONSISTENCY H H H H H H M M M M M L AFTER 06Z WEDNESDAY... IFR possible in stratus Tuesday night, and in possible snow showers Thursday through Thursday night. all mainly in the mountains, && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Freezing Rain Advisory until 7 PM EST this evening for WVZ523>526. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/SL NEAR TERM...TRM SHORT TERM...SL LONG TERM...SL AVIATION...TRM

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