Area Forecast Discussion
Issued by NWS Charleston, WV

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295 FXUS61 KRLX 222021 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 321 PM EST Wed Feb 22 2017 .SYNOPSIS... Unseasonably warm weather returns again Thursday and Friday. A strong cold front crosses first thing Saturday morning, followed by cooler weather for the weekend. && .NEAR TERM /THROUGH THURSDAY/... As of 3 PM Wednesday... Wave was quickly exiting the area this afternoon, taking the last of the rain with it. Stratocu is likely to linger tonight, limiting fog formation but still do expect some. Thursday will bring a continuation of south to southwest flow with low level moisture remaining in place. Heating is forecast to increase CAPE to 500-700 J/KG. This, along with weak shear, could give rise ton a few thunderstorms as a weak upper level short wave trough crosses in west to southwest flow, but nothing organized is expected. Temperatures close to a blend MET/MAV and bias corrected consensus. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... As of 310 PM Wednesday... Models continue to slow down frontal passage. Latest ECMWF and NAM guidance having the front near the Ohio River by 12Z Saturday and the GFS continues to bisect WV with the front by that time. I have held off on PoP until a few hours later than previous forecast, with Categorical PoP in the Ohio Valley between 6Z - 7Z, but this may still be a bit early. The main concern with this front will be the possibility of isolated damaging wind gusts in convection. Overall, instability is rather weak, with NAM and GFS indicating anywhere from 300 to 600 J/Kg of CAPE with the highest values in the Ohio Valley. However, wind shear values are very impressive with 65 to 70 knots of 0 - 6km bulk shear. Also, upper trough turns slightly negative as it crosses the region and 700mb to 500mb lapse rates increase to 8C/km. It is possible that we could see a weakening QLCS entering the Ohio Valley by early Saturday morning. With the impressive wind shear and modest instability in the Ohio Valley, there is a chance that convection could bring some strong wind gusts down to the surface. With the overnight timing of the front though, the threat for damaging winds will be low, but isolated damage and power outages will be possible in the Ohio Valley and that threat will decrease heading east across West Virginia. The cold front clears the area on Saturday and strong cold air advection pushes in behind it. There may be enough lingering moisture with the upslope NW flow behind the front that the mountains squeeze out a few snow showers. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 315 PM Wednesday... Start off the long term with high pressure over the region, but this will be short lived as zonal pattern is set up across the U.S. Guidance is in a little better agreement with southern stream wave pushing across the area on Monday. This will be the first of what looks like several systems moving through the progressive pattern next week. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... As of 115 PM Wednesday... Rain will slowly move out of southern Wv this afternoon, followed by slowly improving conditions. IFR conditions at HTS and CRW should improve by around 21Z or so. There is a chance IFR conditions develop at BKW around 21-23Z. Farther north, MVFR stratocu over the middle Ohio valley may get to CKB for a time this evening. Stratocu will be mainly above 3 kft tonight, but MVFR fog may form. Showers may bring MVFR conditions into the middle Ohio Valley by midday Thursday. Otherwise VFR conditions are expected through 18Z Thursday. Surface flow will be light south beneath light to moderate southwest aloft. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: IFR may vary this afternoon at HTS, CRW and BKW. Fog formation tonight is in question. 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 M L M M M H H H H H H L HTS CONSISTENCY H H M M M H H H H H M L BKW CONSISTENCY H H M M M M H H H H H L EKN CONSISTENCY H H H H H M H L M M M M PKB CONSISTENCY H H H H H H H M M H L L CKB CONSISTENCY H H H H H H M M M H M L AFTER 18Z THURSDAY... No widespread IFR conditions are expected at this time. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/MPK NEAR TERM...TRM SHORT TERM...MPK LONG TERM...MPK AVIATION...TRM is the U.S. government's official web portal to all federal, state and local government web resources and services.