Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 221735 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 135 PM EDT FRI JUL 22 2016 .SYNOPSIS... Low level moisture on the increase today. Weak disturbances drop southeast today and Saturday. Front stalls in Upper Ohio Valley Saturday night. && .NEAR TERM /THROUGH TONIGHT/... Latest radar mosaic shows broken line of showers/storms has pushed into portions of Perry County at this time. Short-term models suggest that these storms should weaken as they continue to push southeast. However...they appear to be maintaining their intensity and coverage. Have tweaked PoP grids...especially across southeast reflect my thinking that these storms should continue to push southeast for a few hours before weakening. Otherwise...nothing more than tweaks are needed. Previous Discussion... Upper clouds streaming through early this morning associated with an MCS to our west. Dirty ridge just to our west through the period, and will have some week upper disturbances drop down the eastern side of the ridge today into tonight. With these, have isolated to scattered showers and thunderstorms...with the highest POPs across the Mid Ohio River Valley. The amount of instability today will depend on how thick the high clouds remain this morning. There is definitely a good deck of cirrus to our northwest associated with the MCS. NAM does show recovery to 1000-2000 j/kg CAPE this afternoon across western half of CWA, which would be enough for some taller storms capable of gusty winds. The atmosphere should be warm enough to limit hail production. Shear is very weak so storms should be rather pulsey and not become well organized. Precipitable water values top 2 inches along and west of the Ohio River, indicating downpours are also possible in any thunderstorms. Blended ECMWF mos into previous forecast, with only minimal changes. Mainly a bit warmer overnight. Today will be a warm day, with increasing dewpoints. Heat indices top out just below advisory criteria this afternoon -- in the mid and upper 90s across the lowlands. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... The heat wave will continue this weekend with temperatures reaching the lower 90s. Models show a dry column through the period with some moisture at the mid levels and high sfc CAPE values. Can no ruled out low chance for showers and storms by Sunday afternoon. A weak cold front becomes stationary in the vicinity to our north. Convective complexes can develop under northwest flow. Remnants of these complexes can dig southeast while diminishing in intensity. This will bring debris clouds to the area. Despite the clouds, temperatures will climb again Sunday mainly lowlands. Moisture and hot temperatures can make heat index to climb into the 100s this weekend. Went with the superblend guidance for temperatures through the period. Continued advertising possible heat advisories for the weekend. && .LONG TERM /MONDAY THROUGH THURSDAY/... It will turn more unsettled early next week with the arrival of a frontal boundary coupled with a s/w trof passage. These features will make a run toward the area later on Monday with convection chances increasing thru the afternoon and especially into the evening hours. The upper ridge will flatten as the overall pattern turns more zonal with generally weak flow through the atmosphere. This will keep the unsettled pattern going thru Tuesday as the the front will be in no hurry to push through. With the light flow and high pwats...some slow moving downpours are in the cards. The front finally gets a nudge to the S by Wednesday with mid level drying spreading into the area keeping afternoon shra/tsra chances confined over S WV/SW VA in the better moisture. Temps will gradually ease back closer to normal levels midweek...likely ending the heat wave over portions of the area Monday. && .AVIATION /18Z FRIDAY THROUGH TUESDAY/...
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18Z FRIDAY THROUGH 18Z SATURDAY... Latest radar mosaic continues to indicate scattered showers and storms with MVFR...local IFR...conditions were pushing across southeast Ohio. Outside of the area...vfr conditions prevailed. An upper level disturbance will push southeast into the nighttime hours. As a result...the storms should continue to move/develop southeast during the afternoon hours. The best chance will be along and west of the Ohio River, and have continued VCTS on the PKB and HTS TAFs into the evening hours. Models still fairly insistent on fog formation tonight, but think there will be enough remnant clouds around to allow for dense fog formation. Have generally gone with 6sm br between 08Z and 12Z everywhere...with some 3-5sm br in favored river places like CRW/EKN. VFR conditions are expected after 13Z...with isolated storms possible after 15Z. CONFIDENCE AND ALTERNATE SCENARIOS... FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: May need to expand VCTS this afternoon and evening. Dense river valley fog may form tonight. 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 10 11 12 13 14 15 16 17 18 19 20 21 EDT 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 CRW CONSISTENCY M M H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY L L M H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z SATURDAY... IFR possible in thunderstorms late Monday.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...ARJ/MZ/30 NEAR TERM...JSH/MZ SHORT TERM...ARJ LONG TERM...30 AVIATION...JSH is the U.S. government's official web portal to all federal, state and local government web resources and services.