Area forecast discussion National Weather Service Charleston WV 344 am EDT Tuesday may 21 2013 Synopsis... afternoon convection Tuesday and Wednesday. Cold front approaches Wednesday and moves across Thursday. Cooler high pressure Friday and the weekend. && Near term /through tonight/... big question is how will the complex over Illinois/in affect our region today. None of the models seem to have a great handle on the complex...so confidence is not high. Mesoscale NAM and some other models show a line of convection forming off the moisture from this complex and moving either across the forecast area...or into the western portions of the area. Based on the mesoscale models...will lower probability of precipitation this morning...but raise probability of precipitation in the west this afternoon. GFS MOS looks too warm for highs today...so went closer to the NAM MOS. && Short term /Wednesday through Friday/... short term period starts out with the County Warning Area in the warm sector of low pressure system that will push east across the Great Lakes region early in the period. Conditions will continue to be warm and humid on Wednesday in the southerly flow out ahead of the approaching cold front and upper trough. Temperatures on Wednesday are not expected to be as high as on Tuesday...due to expected cloud cover...and precipitation. Wednesday will see increased shower and thunderstorm activity as the cold front and upper trough pushes closer to the area. Several embedded shortwaves will round the base of the trough...and move northeast through the area. Still looking like there could be severe weather on Wednesday...particularly in southeast Ohio...eastern Kentucky...and WV counties near to the Ohio River as good upper dynamics...instability...and 0-6km bulk shear of 30+ kts will exist. Strong/damaging winds...and hail will be primary threats...with fzlvs prognosticated to be around 11k feet. Cold front will end up somewhere along/near southeast Ohio zones by 12z Thursday. Upper trough will push through the area Thursday and Friday...keeping a mention of showers and thunderstorms in the forecast through at least Thursday night. Much cooler and drier air is expected to work its way into the County Warning Area for the weekend as high pressure across the north builds in. && Long term /Friday night through Monday/... have generally followed wpc thinking for this portion of the forecast. Cold front should be located southeast of the region at the beginning of the period...with high pressure building in. Chance of showers and storms will end from the northwest Thursday night into Friday. However...a middle-level disturbance moving southeast will increase the chances for precipitation on Friday....mainly in the mountains and adjacent counties. High pressure will then be in control of the area into Monday. However...a weak middle-level disturbance will slide southeast Saturday night into Sunday. A warm front will develop and approach the region on Monday. European model (ecmwf) suggests there will be a chance of showers and storms Monday afternoon...especially across the south. Because of uncertainty...have left these chances out of the forecast for now. && Aviation /08z Tuesday through Saturday/... patchy dense fog can be expected in valleys in and just west of the mountains that received rain today. Further west and on hilltops...winds should prevent the dense fog. Cumulus can be expected today...with afternoon and evening thunderstorms possible. Forecast confidence and alternate scenarios through 06z Wednesday... Forecast confidence...moderate with fog early this morning...then high. Alternate scenarios: some uncertainty on fog density and coverage overnight. Timing of showers and thunderstorms this afternoon could vary. Experimental table of flight category objectively shows consistency of weather forecast office 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 Tuesday 05/21/13 UTC 1hrly 08 09 10 11 12 13 14 15 16 17 18 19 EDT 1hrly 04 05 06 07 08 09 10 11 12 13 14 15 crw consistency h h h M h h h h h h h h heights consistency h h h h h h h M h h h h bkw consistency l l l l l h h h h h h h ekn consistency l l l l l l 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 06z Wednesday... IFR conditions possible Wednesday with showers and thunderstorms. && Rlx watches/warnings/advisories... WV...none. Ohio...none. Kentucky...none. Virginia...none. && $$ Synopsis...rpy/sl near term...rpy short term...sl long term...jsh aviation...rpy