Fast moving areas of low pressures to produce widespread accumulatingsnows across the Central Plains, Mid Mississippi Valley, Ohio Valley,Central Appalachians, Mid Atlantic, Northern New York and New England...Heavy precipitation to move into Northern to Central California onSaturday.Heavy rains possible for South Texas...Below average temperatures to spread southeast from the NorthernPlains.Active Lake effect snows downwind of the Great Lakes Friday andSaturday.Two fast moving areas of low pressure pushing from west to east will beproducing widespread areas of accumulating snows across large portions ofthe Lower 48.   The lead area of low pressure will be moving eastwardtonight from the eastern Lakes region, across northern NY State and intoNew England.  This system will produce a brief period of snow, withaccumulations of several inches from northern New York State into portionsof central to northern New England.  In the wake of this system, cold airmoving across the relatively warm and ice free Great Lakes will supportwidespread lake effect snow showers downwind of the Great Lakes.  Locallyheavy snowfall totals possible in the favored lake effect areas across theUpper Peninsula of Michigan and across portions of north central tonorthwest New York State, to the east of Lake Ontario. This first fast moving area of low pressure will be followed by a secondmoving quickly east northeast from the Southern Plains Friday, into theTennessee Valley Friday night and off the Mid-Atlantic coast earlySaturday.  An area of snow will develop well to the north of the surfacelow track, with accumulating snows possible from portions of the CentralPlains. east into the Mid Mississippi Valley, Ohio Valley, CentralAppalachians and Mid-Atlantic.  The fast movement of this system will adetriment to heavy totals, with generally 1 to 3 inches of accumulationforecast across these areas, with isolated heavier totals possible. Below average temperatures will be spreading south and southeastward from theNorthern Plains/Upper Mississippi Valley.  This will produce a belowaverage temperature day on Friday across the Northern to Central Plainsand Upper Mississippi Valley, with these below average temperaturesspreading south into the Southern Plains and eastward into the Middle toLower Mississippi Valley, Ohio and Tennessee Valleys on Saturday.  Whilethese colder than average temperatures are a departure from recent warmthacross this regions, the cold shot will be short lived with temperatureswarming from west to east late in the weekend and into next week.The current stormy pattern across the eastern Pacific will be pressingeastward on Friday into Saturday, with heavy precipitation pushing backinto Northern to Central California on Saturday.  This precipitation isthe beginning of a wetter pattern for California, with additional heavyprecipitation likely for much of California for the beginning of nextweek.  The first round of heavy precipitation does have the potential toproduce isolated flash flooding across the central to northern Californiacoastal regions.    The additional heavy rains slated for early next weekwill also pose a flash flood threat, with this threat pushing farther tothe south into central to southern California.An expanding area of rain also likely to develop Thursday night/earlyFriday morning across South Texas, persisting into the day on Saturday. This rainfall will also push east northeastward Friday into Saturday alongthe northern Gulf coast and into North Florida.  The heaviest totalsexpected for South Texas where rainfall accumulations of 1 to 3 inches arepossible.