Area Forecast Discussion
Issued by NWS Charleston, WV

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125 FXUS61 KRLX 021900 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 200 PM EST Fri Dec 2 2016 .SYNOPSIS... Cooler high pressure this weekend. Weak upper trough late Sunday into Sunday night. Warm front Monday night Tuesday. Milder mid week. && .NEAR TERM /THROUGH SATURDAY/... As of 130 PM Friday... Low stratus behaving as expected thus far today with Nam Nest model having an excellent handle on this. There is an area of weak CAA embedded within a belt of vorticity advection pivoting thru OH, helping to produce an area of sprinkles and drizzle. Expect this to pivot thru the northern half of WV late this afternoon with a chance of a sprinkle or drizzle. This should translate to snow showers across the northern mountains, though there is a concern that ice crystals will be hard to come by given a meager moisture depth. Still, the northern mountains seem to find a way to flake despite cloud top temps/lift extending only to -6C. Allowed for a few tenths of accumulation overnight. The bigger conundrum centers around what to do with the stratus. Most of the models show enough drying beneath the inversion to allow for more of broken deck late tonight and lingering on Saturday. The Nam Nest has had the hot hand so will lean on it for sky coverage through tomorrow. Even if there is some partial clearing over SE OH and parts of WV into early Saturday. Low confidence on eradicating the stratus completely late tonight into Saturday. Even if some partial clearing takes place...this should be short lived as cirrus advects in from the SW in Saturday afternoon. Temps tonight will be entirely dependent on cloud cover. Have gone a bit above guidance given the aforementioned thinking. This is also reflected for highs tomorrow with cooler temps north and warmer toward KY. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 330 AM Friday... Upslope rain and snow showers in the mountains diminish early Saturday morning, as high pressure builds toward the area with drier air. Low level northwest flow does continue, but the cold advection ceases as the thermal trough passes. The high crosses early Sunday morning, followed by the upper level ridge. The next upper level short wave trough crosses Sunday afternoon into Sunday night. This looks like a split system with little surface reflection, with most of the associated precipitation passing to the north and to the south of the forecast area. Therefore have only slight chance to chance PoPs, highest south, Sunday afternoon and night. High pressure crosses late Sunday night into Monday, followed by upper level ridging Monday evening. An upper level short wave trough digging into northwest Mexico early this morning, closes off there Saturday morning, and then ejects out into TX Monday morning, and then dampens out as it moves up the Ohio Valley Tuesday morning. This and its attendant surface low pressure system and associated warm advection and dynamics should result in rain overspreading the forcast area quickly as dawn Tuesday approaches. Temperatures were kept generally close to guidance. Light snow showers are possible Sunday night in northern WV, especially in the mountains. Temperatures should rise above freezing as the next system approaches Monday night, but did allow for some light snow at the front end in the northern WV mountains Monday night. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 330 AM Friday... Dampening upper level short wave trough lifts through the area on Tuesday, allowing rain to taper off from southwest to northeast Tuesday midday and afternoon. Beneath upper level southwest flow in the wake of the dampening system, a lack of cold air means any lingering showers or drizzle in the wake of the system Tuesday night will remain liquid. Weak high pressure crosses on Wednesday, but lingering low level moisture, and the short break between systems, results in a small chance for rain remaining in the forecast.. Models start to diverge on the timing of the next system later in the week in this active weather pattern. Went with a compromise, with a strong cold front sweeping through the area sometime on Thursday. Strong cold advection following the front will change mainly upslope rain showers over to snow showers in the mountains sometime Thursday, before ending Friday morning. Temperatures close to guidance, with very cold air moving into the area by Friday, when models concur on h85 temperatures of 18 to 20 C below 0. This would be the coldest air of the season so far, with the new day 7 highs at or below freezing Friday. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... As of 130 PM Friday... Expansive stratus deck over the area providing for MVFR cigs thru this evening. Some patchy drizzle or sprinkles possible across N WV but should not restrict vsby below VFR. This will translate to shsn across the northern mountains with cigs/vsby should stay below IFR. Low confidence tonight into Saturday due to questions concerning the staying power of the stratus deck. Current thinking is some improvement into low end VFR tonight as the stratus lifts a bit before perhaps lowering once again toward morning. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY... FORECAST CONFIDENCE: Low ALTERNATE SCENARIOS: Timing of category changes in clouds may vary. Possible clouds could break up more overnight, resulting in more widespread VFR than currently forecast. 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 H H H H H H M M M L L HTS CONSISTENCY H M M H M M M M M M M M BKW CONSISTENCY H M L L L L L L L H H L EKN CONSISTENCY H M L L M L H L H M L L PKB CONSISTENCY H H H H H H M M M M M M CKB CONSISTENCY H H H H H M H H L M M L AFTER 18Z SATURDAY... Brief IFR possible in -shsn at higher mountain ridges into Saturday afternoon. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...30/26 NEAR TERM...30 SHORT TERM...TRM LONG TERM...TRM AVIATION...30 is the U.S. government's official web portal to all federal, state and local government web resources and services.