Rainy, stormy weather continues along the East Coast through Thursday,lingering in New England Friday......Unsettled weather for the West, with a late season Atmospheric Riverimpacting California Friday......Warming trend begins over Central U.S. on Thursday...Showers and storms will continue along the East Coast Thursday as a pairof slow moving cold fronts pass through the region. Locally heavy rainfallis expected over portions of eastern North Carolina and southeasternVirginia where a wave of low pressure will help to enhance convergence andstorm converge/intensity. A Slight Risk of Excessive Rainfall (level 2/4)will continue through the overnight hours Wednesday into the day Thursdaywith some scattered instances of flash flooding possible. Storms willbegin to clear the coast from south to north through the day Thursday asthe lead front pushes into the Atlantic, lingering longest in New England.Here, an intensifying area of low pressure off the coast will keep moistonshore flow into the region through Friday. Some of the rain may be heavyat times Thursday along the coast, leading to some areal flood concernswhen combined with snowmelt. Precipitation is expected to change over tosnow for interior locations of the region by Friday night, with some lightto moderate accumulating snowfall possible. Winds will also become a bitgusty Friday as the low deepens offshore.Areas of lower elevation coastal/valley rain and higher elevation/mountainsnow will continue across the West Thursday and Friday, generallyspreading further southward and eastward as a frontal system moves throughthe region. Some locally heavier snow totals will be possible for regionalmountain ranges from the Pacific Northwest southward into northern/centralCalifornia, as well as for the eastern Great Basin into thenorthern/central Rockies. The greatest impacts are expected in thenorthern Sierra through Thursday morning where a Winter Storm Warning isin place. A more intense system over the Pacific will approach Californiaon Friday, bringing an enhanced onshore flow of anomalously highmoisture/Atmospheric River directed at portions of central and southernCalifornia. Rainfall will pick up Friday into Friday night/Saturdaymorning along upslope portions of the Transverse Ranges, where a SlightRisk of Excessive Rainfall is in place, as a few inches of rainfall maylead to flooding, especially for terrain sensitive areas. This threat willcontinue into the weekend beyond the current forecast period.Elsewhere, some snow showers will linger Thursday for portions of theUpper Midwest/Great Lakes, particularly close to the Canadian border, as alow pressure system departs the region into Canada. A shortwave followingthis system will bring some additional light rain/snow showers to theNorthern Plains into the Upper Midwest on Friday. Temperature-wise, somechilly morning lows dropping into the low to mid-30s are forecast Thursdayacross portions of the Mid-South into the Tennessee Valley following acold front passage, with Frost/Freeze-related advisories and warnings inplace for newly greening sensitive vegetation. Increasing upper-levelridging following the system over the East Coast and ahead of troughingover the West will bring warmer, above average temperatures broadly acrossportions of the High Plains Thursday, and into the Plains/MississippiValley/Midwest on Friday. Highs will remain either around or below averagealong the East Coast and across most of the West with the upper-leveltroughing in place.