Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 051123 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 623 AM 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 TONIGHT/...
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As of 620 Am Monday... Forecast is on track. As of 330 AM Monday... Cancelled winter weather advisory for early this morning in conjunction with neighboring offices, as precipitation has tapered off to spotty drizzle, and temperatures were slowly climbing above freezing in the advisory area. 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.
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&& .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... As of 245 AM Monday... The active weather pattern continues in the short term period. Precipitation returns to the CWA on Tuesday, as a shortwave trough and attendant surface low lifts northeast out of the Gulf of Mexico region towards the area. Good lift/ascent on Tuesday, along with above normal PW values, will result in a good soaking rain for much of the CWA. There still exists the potential for freezing rain through early Tuesday afternoon across Randolph and Pocahontas counties as the potential for near or below freezing temperatures at the surface exists, along with increasing southeasterly flow. Depending on timing of system, may need to address the situation with a freezing rain advisory. Will highlight this in the HWO. In addition, could be a bit breezy at times on Tuesday particularly across higher terrain, but overall, no headlines expected. The low and associated cold front will push east of the CWA Tuesday evening, with decreasing precipitation as it does so. Will likely transition to -dz across much of the area Tuesday evening as deeper moisture is lost. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 245 AM Monday... Wednesday looks to be dry and cool, with high pressure nudging in from the west. However, the weather will become colder by Thursday and Friday, as an upper level trough deepens across the eastern U.S.and Canada. Temperatures will steadily fall throughout the day on Thursday, with light rain and snow showers developing on Thursday as favorable northwesterly flow develops off the Great Lakes. At least light accumulations will be possible in favored upslope areas in the mountains. -shsn expected to continue across the higher terrain through at least Friday night in nwly flow. && .AVIATION /12Z MONDAY THROUGH FRIDAY/...
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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 12Z 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. DATE MON 12/05/16 UTC 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 EST 1HRLY 05 06 07 08 09 10 11 12 13 14 15 16 CRW CONSISTENCY M M M M H H H H H H M L HTS CONSISTENCY M M H H H H H H H H L L BKW CONSISTENCY L L M M M M H H H H M M EKN CONSISTENCY M M L L H H H M M H M M PKB CONSISTENCY M M H H H H H H H H M M CKB CONSISTENCY H M M M M H H H H H L M AFTER 12Z 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... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/SL NEAR TERM...TRM SHORT TERM...SL LONG TERM...SL AVIATION...TRM

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