TRENTON, New Jersey (AP) Flood watches were in effect across much of New Jersey, Pennsylvania, Ohio and New York today as rain moved in and threatened to raise already swollen waterways out of their banks.A rising Ohio River shut down a Cincinnati public school on Thursday and some low-lying roads in the area, forecasters said.New Jersey’s Gov. Chris Christie declared a state of emergency on Wednesday so state police and the National Guard could mobilize forces in advance of the storm that was heading north after soaking the Southeast, where it tore roofs off buildings and flipped cars.Rainfall amounts of 3 inches or more were forecast for portions of northern New Jersey where streams are still running high from a weekend storm that flooded many basements and forced evacuations in some low-lying areas.The National Weather service warned of possible flooding in several New Jersey counties where a light, steady rain was falling today and heavy rain was likely. It told residents of portions of New York’s Lower Hudson Valley to watch out for flooding, too, because 2 to 3 inches of rain were expected to fall from Thursday morning and into Friday.In Ohio, Cincinnati school officials said in a news release that today’s closing of Riverview East Academy was the first due to river conditions at the school, near the banks of the Ohio on the city’s east side.The National Weather Service said the river was nearly 2 feet above its official flood level Thursday morning and was expected to rise 2 feet more by Friday evening.Heavy rains over the past week and a-half have swelled rivers and streams throughout Ohio.The rain was expected to be fairly heavy in areas north and west of New York City and Connecticut by the Thursday morning rush hour. Flood watches extended up to the Buffalo area and into the Adirondacks, where forecasts also call for several inches of snow.Snow was expected in northeast Ohio as well. Wet snow is expected to begin falling on the region late Thursday and possibly carry into Friday afternoon. Up to a foot of snow could accumulate, with the heaviest expected from the Akron area east to Youngstown and the Pennsylvania line.Just a few days ago, a wild mix of snow, sleet and rain battered a wide swath of New England and upstate New York, dumping nearly 30 inches of snow on some areas, knocking out power to tens of thousands of utility customers, washing away homes and leaving many rivers and streams at high levels. Those swollen waterways, combined with the saturated soil, could result in moderate to major flooding, weather officials warned.Weather advisories and flood watches were posted for much of Pennsylvania, where the storm system was expected to carry heavy rain to many areas and snow to some. A coastal flood watch also was posted.In New Jersey, Gov. Chris Christie signed an executive order declaring a state of emergency late Wednesday in anticipation of flooding along the Ramapo, Passaic, Delaware and Raritan rivers, allowing emergency responders to mobilize early.The Passaic River already is above flood stage in some spots and isn’t expected to crest until Saturday.