A shower or two North Jersey, NYC and Eastern Pa ..... Fair Atlant... Showers and T-storms DFWUnsettled weather and severe thunderstorm chances gradually expandacross parts of the central and southern Plains over the next couple ofdays......Above average temperatures across much of the western half of thecountry while cooler than normal weather prevails in eastern half...The relatively benign weather pattern lately across the country isexpected to gradually become more active in the course of the next coupleof days as a low pressure system is forecast to develop and intensify overthe central Plains.  The upper-level trough responsible for developing thelow pressure system is currently located over the subtropical easternPacific, moving toward Baja California.  This upper trough is forecast toreach the southern Rockies on Thursday as the low pressure systemintensifies more rapidly over the central Plains later that day.  Showersand thunderstorms associated with the leading warm front across OklahomaWednesday night is forecast to expand northward across the central Plainsduring the day on Thursday and reach into the northern Plains by evening. The thunderstorm activities will likely get stronger later in theafternoon on Thursday over the central Plains ahead of a dry line.  Windswill also strengthen throughout the central Plains on Thursday as the lowpressure system intensifies. In the meantime, a weak low pressure wave and a pair of cold fronts willspark showers and embedded thunderstorms into tonight across the GreatPlains and parts of the Midwest.  Some stronger thunderstorms may developover western Texas this evening associated with a cold front.  Bylater tonight, the Midwest should begin to clear out from the showers andstorms as they move into the Ohio Valley.  Wednesday will see these stormssettling south across Oklahoma into the Tennessee Valley and into portionsof the Mid-Atlantic.  Meanwhile, rapidly falling temperatures behind thesecond cold front are expected to end the rain as a period of wet snowacross northern New England during the day on Wednesday.  Meanwhile, thetrailing cold front entering the southern Plains will be the focus forthunderstorms across the southern Plains on Wednesday, and they willexpand northward as the aforementioned low pressure system intensifies.Elsewhere, unsettled weather is also in the forecast throughout parts ofthe Great Basin and eventually the Pacific Northwest by Thursday asinitial upper ridging and well above average temperatures gradually erode.Much of the rainfall is expected to be mostly beneficial outside of anylightning potential with thunderstorms over the central Great Basin. Highsthroughout the southwest are anticipated to reach the 80s and 90s throughWednesday, with 60s and 70s for much of the Intermountain West.Cooler weather is in store for the Great Lakes and much of the easternU.S. behind the cold fronts.  The cooler temperatures are forecast toreach into the Carolinas on Thursday.  Meanwhile, above averagetemperatures will prevail across much of the western U.S. before the uppertrough brings cooler temperature as temperatures reach well up into the80s to near 90 over the southern High Plains by Thursday afternoon.