Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 230738 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 338 AM EDT Fri Mar 23 2018 .SYNOPSIS...
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High pressure exits tonight. Another low pressure system this weekend. Dry start, with a warming trend, to start next week.
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As of 320 AM Friday... A beautiful end to the work week with weak high pressure nosing in from the north. Some stratocu may form across the northern lowlands and northern mountains this afternoon, courtesy of weak CAA. Otherwise, a mainly sunny sky with moderating temperatures, though still well below normal. I do expect a pretty decent fall in temperatures this evening, with light flow and very dry air in the low levels. As the night progresses and high and mid level clouds work through, temperatures should level off heading into the predawn hours. Attention then turns to the potential winter storm poised to affect the southern half of the CWA Saturday. There remains differences between the NAM and basically the remainder of the global model suite, including the ensemble runs. The NAM appears to be overly aggressive with the WAA with a system whose mid and upper level support will be shearing out in confluent flow across the mid atlantic region. Thus this northern solution has largely been discounted, but not totally. We are relying on the model and esembles consensus for the nitty gritty details, but stressing there is still some wiggle room given the NAM solution. Impressive isentropic lift amid a tight thermal gradient centered on H85, will allow for strong frontogenetic forcing to setup in a narrow zone across the southern portion of the CWA, primarily just beyond the near term. Expect a band of precip to advance into far western and southern zones by 12Z Saturday. Model soundings suggest mainly snow as good wetbulbing allows any residual warm nose in the boundary layer to quickly cool as precip rates increase.
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&& .SHORT TERM /SATURDAY THROUGH SUNDAY/... As of 420 PM Thursday... Low pressure, and its attendant upper level short wave trough, tracks east-southeast, and pass of the area, late friday night through Saturday. Models have come into better agreement on this southward track, with impacts mainly across central and southern portions of the area. Like on Wednesday, the daytime temperatures across the lowlands will be right near or a little above freezing, so the early spring insolation will easily be able to limit accumulations there. These temperatures were lowered a bit from central guidance Saturday morning into Saturday afternoon. Models also minimize the warm nose aloft, which, together with the boundary layer warmth of early spring, all but eliminates the possibility for freezing rain, Sleet is also limited, though there may be small pellets at the end Saturday night, as the moisture depth decreases out of the favored dendritic growth zone, and the out of the ice in cloud zone. Central guidance reflected the higher of the QPF solutions among the two highest operational models. Even with that, snow totals are at or slightly below previous values. This places totals near advisory criteria in NE KY, and near warning criteria for but a small sliver of the higher mountainous terrain, but only when comparing 12-hour criteria with 24 hour amounts, 06Z Saturday through 06Z Sunday. Thus have decided to hold off on a winter storm watch for now, as only half a county would be under consideration at this time, and advisories would come later as needed. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... As of 420 PM Thursday... High pressure and upper level ridging dominate to start the period, with a warming trend through Wednesday. However, a frontal system with multiple weak waves moving along it, slowly approaches during this time. This gives rise to the chance for rain starting Tuesday, as the upper level ridge flattens, and northern and southern stream short wave trough approach from the west Wednesday through Thursday, pushing the surface front closer. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... As of 142 AM Friday... Building high pressure will provide widespread VFR conditions through the period most of the period. Some lingering stratocu across the southern mountains will dissipate this morning. Some weak CAA may allow for stratocu to form in the afternoon across the northern mountains, affecting CKB and EKN. Again, still looking at VFR as bases hug around 4 kft. High clouds advance into the area overnight tonight with bases lowering toward dawn Saturday. Thereafter, a band of heavy wet snow will work northeast into southern terminals 12 to 15Z, with IFR or worse conditions. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY... FORECAST CONFIDENCE: High. ALTERNATE SCENARIOS: None. 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 FRI 03/23/18 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 CRW CONSISTENCY H H H H 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 H H H H H H H H H H M EKN CONSISTENCY H H H H H H H H H H H M PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY H H H H H H H H H H H M AFTER 06Z SATURDAY... IFR in rain/snow with the next system on Saturday. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...RPY/30 NEAR TERM...30 SHORT TERM...JSH/TRM LONG TERM...JSH/TRM AVIATION...30 is the U.S. government's official web portal to all federal, state and local government web resources and services.