Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 031457 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 957 AM EST Sat Dec 3 2016 .SYNOPSIS... Chilly high pressure this weekend. Weak upper trough late Sunday into Sunday night. Low pressure Monday night Tuesday. Briefly milder in its wake mid week, then much colder late week. && .NEAR TERM /THROUGH TONIGHT/...
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As of 945 AM Saturday... Updated the grids this morning to go more pessimistic for sky cover. Hard to see this stratus eroding for any significant breaks before the cirrus canopy works in. As a result, also knocked down highs a tick or two. As of 430 AM Saturday... -DZ, along with isold -shsn, particularly across the higher terrain, will taper off later this morning into early afternoon, as high pressure builds into the region, and flow becomes less favorable for upslope. Still looking at yet another cloudy cool day, with low level moisture remaining trapped beneath inversion in light flow pattern. Overnight, kept temperatures several degrees warmer than guidance with overcast sky expected. Some light precipitation will move into southwest Virginia and southern WV zones towards the end of the period as moisture from the gulf advects into the region, and an upper shortwave trough pushes east into the Great Lakes Region during the day Sunday. Still a bit of uncertainty in precipitation type across aforementioned areas early Sunday morning, but at least a brief wintry mix at the onset looks to be likely, with little to no accumulations expected due to brief duration, and light qpf, before changing over to all rain.
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&& .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... As of 430 PM Saturday... Precipitation overspreads the area from southwest to northeast on Sunday, as a weak short wave trough crosses. This will be a split system, with the best forcing associated with the short wave passing north of the forecast area. However, channeled vorticity and southern stream moisture will make for another precipitation maxima to the south. With this maxima coming close to the forecast area from the south, precipitation is most likely late Sunday far southern portions of the forecast area, mainly the southern mountains. Precipitation may begin as a wintry mix far south first thing Sunday morning, but low level warming will bring about a quick change over to rain, without much accumulation or hazard. As the system moves off to the east on Sunday night, there may be enough cold air aloft for a wintry mix in the northern mountains. However, since the moisture layer will be becoming shallow, lack of ice crystals may lead to just drizzle / freezing drizzle but, again, not much hazard. Weak Pacific high pressure crosses Monday, as upper level ridging crosses late Monday. This will be quickly followed by the next system, an upper level closed low over northwest Mexico early this morning, that ejects out into TX early 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, will result in rain overspreading the forcast area quickly as dawn Tuesday approaches. The rain will diminish from southwest to northeast Tuesday as the system lifts on through. Little in the way of cold air initially follows the system Tuesday night, so an overcast, damp night appears in store, but any lingering precipitation will be light, and primarily of the liquid variety. Temperature close to a raw and MOS based blend. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... As of 430 PM Saturday... Much colder air arrives this period, but with lingering questions as to when the colder air arrives. Models disagree on the degree of cold air eventually coming in Wednesday and Wednesday night in the wake of the Tuesday system, and on the timing of a cold front on Thursday. The two factors combined result in a 15 F degree or more spread between temperature outcomes Thursday. The forecast represents a blend, but a little toward the colder solution, per WPC preference and coordination with neighboring offices. Rain showers in the wake of the cold front Thursday are thus most likely to mix with and change to snow showers in the west, and over the higher terrain. Cold canadian air takes over by Thursday night, and dominates through the balance of the forecast, with highs below freezing for the first time this early winter season Friday, and maybe getting back above freezing over the lowlands on Saturday, as upslope snow showers diminish. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
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As of 610 AM Saturday... Widespread MVFR cigs mainly across the mountains of WV, and north central WV. In addition, isold ifr in -shsn/-fzdz through 14Z in the northern mountains of WV including vcnty of KEKN. Otherwise, a general improvement to low VFR much of the area after 18Z, although MVFR cigs may continue to linger across parts of the higher terrain including at site KEKN. Light WNW surface winds, although occasional gusts in the teen kt range possible across the higher terrain. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of category changes in clouds may vary. CIGS across northern mountains including at site KEKN may improve to VFR later today. 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 15 16 17 18 19 20 21 22 23 00 01 02 EST 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY M M M M L H H H H H H M HTS CONSISTENCY H H H H H H H H H H H M BKW CONSISTENCY M M M M H H H H H H H M EKN CONSISTENCY H H H M M M M M M M M L PKB CONSISTENCY H M H H H H H H H H H M CKB CONSISTENCY H H M M M M H L H H M L AFTER 12Z SUNDAY... IFR possible in rain and snow, particularly in the mountains Sunday night into Monday. Additional IFR possible in rain and snow towards mid week.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/SL NEAR TERM...SL/30 SHORT TERM...TRM LONG TERM...TRM AVIATION...SL

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