Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 051846 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 146 PM EST Mon Dec 5 2016 .SYNOPSIS... High pressure crosses today. Low pressure crosses Tuesday. Weak high pressure crosses Wednesday. A cold front crosses early Thursday, followed by much colder weather into the weekend. && .NEAR TERM /THROUGH TUESDAY/... As of 1130 AM Monday... Clouds appear to be breaking up a little faster than expected with partly cloudy skies seen across a large part of the forecast area. with a little more sunshine than expected, decided to bump temperatures up a few degrees. Otherwise, no other major changes anticipated. Previous Discussion... As of 245 AM Monday... Deep layer moisture moved east of the forecast area overnight, as the causative upper level short wave trough and surface cold front push east of the area. Precipitation had diminished to very light rain and drizzle, which will taper off from west to east early this morning. Westerly flow behind the cold front, actually a bit gusty overnight, was eroding the CAD wedge, and any freezing rain or freezing drizzle over the very high terrain will be gone by daybreak, so the advisory could likely be allowed to expire at its 6 AM expiration time. Otherwise any lingering drizzle in the mountians after daybreak should be gone by late morning, and high pressure crossing this afternoon should break the clouds up as the inversion lowers. Higher clouds will lower and thicken tonight, as the next low pressure system approaches from the southwest. This system originates from a closed upper level low over northern Mexico early this morning. It ejects into TX today and then dampens into an open wave as it lifts through the lower MS and then TN valleys tonight. This will cause rain to quickly overspread the forecast area toward dawn Tuesday. Timing of the onset is slower compared with previous runs, so the forecast area remains dry into this evening and all but the far south probably dry through midnight. As the surface low pressure system approaches, a CAD wedge will develop toward dawn Tuesday. That raises the possibility of freezing rain over the higher terrain, just beneath the inversion, where temperatures drop to just below freezing by dawn Tuesday. Updated temperatures and dew points through tonight via a blend of near term guidance, with not much change from previous aside higher values early on. && .SHORT TERM /TUESDAY NIGHT/...
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As of 135 PM Monday... High pressure moves back into the region for Wednesday and brings back a brief period of dry weather before next cold front arrives Thursday. On Thursday, strong cold front pushes through the region and will bring snow showers and well below average temperatures with it. In the NW flow the favorable upslope regions will have the best chance to see accumulating snowfall, however even the lowlands may see a very light accumulation but moisture is limited. Thursday night is expected to be one of the coldest so far this season, with H850 falling to -15C will likely translate to widespread lows in the teens with single digits possible in the mountains. Wind chills could be an issue as well, with conditions reaching as low as minus 10 across parts of the Northern Mountains.
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&& .LONG TERM /WEDNESDAY THROUGH SUNDAY/...
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As of 145 PM Monday... The cold temperatures and NW flow will remain over the region for Friday and isolated snow showers could still be a possibility. Temperatures will remain slightly below average into the weekend. Overall the pattern looks to be zonal with several disturbances quickly moving through the flow into the early half of next week, but the lack of moisture and the fast moving nature of the systems should keep precipitation amounts fairly light.
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&& .AVIATION /19Z MONDAY THROUGH SATURDAY/...
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As of 620 AM Monday.... Conditions were improving somewhat early this morning, as the last of the light rain and drizzle associated with the passage of a cold front overnight was tapering off. Ceilings were generally following the mixing height beneath the post frontal inversion, which was deepening to near 4 kft early this morning. This deepening will be brief, as what becomes a subsidence inversion as high pressure builds in, lowers to 2-3 kft today. So, after brief VFR ceilings east of the Ohio River first thing this morning, MVFR ceilings should dominate much of today. This is because, even with high pressure, light flow and the low December sun angle spell difficulty in eradicating the low level moisture trapped beneath the inversion. Enough dry air may eventually push in below the inversion to break up the clouds late today or this evening, only to find higher clouds already in place. These clouds will lower and thicken tonight, as low pressure approaches from the southwest. Ceilings will lower back to MVFR 08Z to 11Z as rain overspreads the area from south to north. Visibility may drop to MVFR by 12Z south, in rain. West surface winds will diminish today, and then increase from the east to southeast tonight, as low pressure approaches. Southeast winds will become gusty on the ridges toward 12Z Tuesday. Light to moderate west to northwest flow aloft will diminish today, and then become light southeast tonight, and then light to moderate south overnight. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing and heights of mostly MVFR ceilings 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. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H M M M H H H H H H H M HTS CONSISTENCY H H H H H H H H H H H M BKW CONSISTENCY H L H H H H H H H H M L EKN CONSISTENCY M H H H H H H H H H H M PKB CONSISTENCY H M M H H H H H H H H M CKB CONSISTENCY M M M H H H H H H H H M AFTER 18Z TUESDAY... IFR possible in rain on Tuesday, and in possible snow showers, mainly in the mountains, Thursday through Thursday night.
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&& .RLX WATCHES/WARNINGS/ADVISORIES...
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WV...Freezing Rain Advisory from 2 AM to 7 PM EST Tuesday for WVZ523>526. OH...None. KY...None. VA...None.
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&& $$ SYNOPSIS...JSH/MPK NEAR TERM...JSH SHORT TERM...MPK LONG TERM...MPK AVIATION...JSH

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