Area Forecast Discussion
Issued by NWS Charleston, WV

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227 FXUS61 KRLX 190247 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 944 PM EST Wed Jan 18 2017 .SYNOPSIS... High pressure pushes into the region tonight. However, active pattern continues, with a warm front crossing Friday, and then a stronger, double-barreled low pressure system early next week. && .NEAR TERM /THROUGH THURSDAY/... As of 945 PM Wednesday... Biggest challenge overnight is the timing of the stratus deck clearing in the south and west. Where this happens, expect fog to form. Only minor updates for now. As of 608 PM Wednesday... Updated forecast to increase sky cover this evening based on current satellite and meso model trends. As of 230 PM Wednesday... High pressure currently centered over Kentucky will continue to the east-northeast. Low level clouds will start to erode across the south later this afternoon and continue northward tonight, but how far north the stratus clears is still uncertain. Will have to watch and see what areas clear out tonight, as the saturated soils with cool overnight temps could develop dense fog in some areas early Thursday morning. Still not enough confidence on if we will see enough clearing and if clearing will take place soon enough for dense fog to develop. Tomorrow will be drier with high pressure overhead and drifting northeast. Will likely see some sunshine across much of the forecast area and this combined with warm air advection will send temperatures soaring. Highs will be close to 60 across much of the south with mid 50s in the north. Mid and upper level clouds will be on the increase afternoon as a warm front approaches from the southwest. Any rainfall will likely hold off until later Thursday night. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... As of 410 PM Wednesday... Warm front pushes northeastward through the area Thursday night into Friday. Decent convergence along the front, and a 50 kt h85 feed will lead to another decent rainfall across the area, keeping soils soggy. The weather dries out southwest to northeast on Friday as the warm front pushes off to the northeast. Low level southwest flow and upper level ridging will then lead to a mild and dry start to the weekend. A major piece of energy coming eastward out of a long wave trough over the western U.S. approaches Saturday and Saturday night. A warm wave out ahead of this system is likely to bring rain, at least to southeast portions of the forecast area, by dawn Sunday. No important deviations from guidance on temperatures, as the January thaw continues. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 410 PM Wednesday... There is general model agreement not only through the extended period, but even out to day ten, when a trend back to colder weather is progged. A distant early signal of this pattern change may be in trends with a major system progged to impact the area early next week. A large upper level low is now progged to move eastward across the gulf states Sunday through Monday, undercutting the east coast ridge, rather than lifting northeastward into it while opening up and dampening out. While the system will not have access to any new cold air, the forecast solution is trending colder by Monday afternoon given a stronger cyclone from the surface through the mid levels tracking farther south and east, now southeast of the forecast area. If these model trends continue, cold air being generated aloft via strong ascent could lead to snow across the very highest terrain as the system starts to pull out Monday night. A stronger closed upper level low tracking south of, rather than over or north of the area, also spells an increased potential for heavy precipitation. The system is actually progged as a double-barreled affair, with a lead warm wave bringing a decent rainfall event Sunday, and then the main low bring another copious shot of rain, at least mainly rain, Monday into Monday night. Will add HWO highlight for the potential for heavy rainfall that could become excessive, given saturated soils and yet another rain event in the short term. This energy is part of an ongoing train of systems with a history of bringing copious amounts of precipitation to the west coast and Cascades. The system pulls out quickly on Tuesday, as another large upper level low moves east across the U.S., pushing a cold front toward the area next Wednesday, day 7. Ridging building into the western states behind the large upper level low signals a pattern change, with the long wave trough position shifting to the eastern U.S, re-opening the door for cold air to come south out of central Canada. Temperatures close to time-averaged guidance, except pulled down toward latest deterministic guidance late Monday into Tuesday. Some of the raw model output shows snow across the highest terrain as early as Monday afternoon. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... As of 608 PM Wednesday... Although high pressure will be building over the area tonight, a stratus deck continues for most of the area. With light warm air advection occurring overnight, should see some erosion of this deck on the southern and western sides, but confidence in timing is low. Areas that do clear may pick up some dense fog. This is complicated even further however by a fairly thick cirrus deck later tonight. With small dew point spreads, think that despite cirrus, low cloud clearing will lead to fog. The remaining stratus deck should raise and form a cumulus deck before dissipating on Thursday. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z FRIDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of stratus deck clearing could vary. Fog may form overnight in areas where stratus clears. 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 THU 01/19/17 UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 EST 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09 CRW CONSISTENCY H H H H H H H H H M M L HTS CONSISTENCY H H H H H H H L L L M M BKW CONSISTENCY M H H H M M M L L M M L EKN CONSISTENCY H H H H H H M H H M M L PKB CONSISTENCY H H H H H H H M M M M L CKB CONSISTENCY H H H H H H H H M M M L AFTER 00Z FRIDAY... IFR possible in rain Thursday night into Friday, and then again at times Sunday through Monday. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/MPK NEAR TERM...RPY/MPK SHORT TERM...TRM LONG TERM...TRM AVIATION...RPY is the U.S. government's official web portal to all federal, state and local government web resources and services.