Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 331 PM EDT Mon Apr 06 2015 Valid 00Z Tue Apr 07 2015 - 00Z Thu Apr 09 2015 ...A wet period is in store for much of the Northwestern U.S. with heavy rain and snow expected for portions of northern and central California... ...Rain and thunderstorms likely across the central and eastern U.S., with a slight risk for flash flooding possible for portions of the Ohio Valley on Wednesday... ...Snow and light freezing rain possible from the Upper Midwest to New England... A pronounced cold front off the coast of northern California will make its way inland overnight tonight spreading some much needed precipitation to drought stricken California. The best moisture, and the heaviest of the precipitation, is expected to occur across much of northern and central California this evening and tomorrow. Most of these places should see heavy rain, except for the highest elevations of northern California and the Sierra Nevada range where as much as a foot or more of snow is expected. As the front makes its way across the Intermountain West, the best moisture supply should get cut off, so lighter and less intense precipitation is expected across the Great Basin and northern/central Rockies Tuesday afternoon and into Wednesday. Across the central and eastern U.S., unsettled weather focuses along a west-to-east oriented frontal boundary where a strong temperature gradient has already set up and will continue over the next several days. To the south of the boundary, where temperatures are expected to be 10 to 20 degrees above normal, showers and thunderstorms will continue to break out as southerly flow out of the Gulf of Mexico pulls plenty of moisture into the region from the Middle Mississippi Valley to the Mid-Atlantic and the Southeast. Heavy downpours may be possible with some of the thunderstorms, and given the recent heavy rain in the same area late last week, additional excessive rainfall with the slight chance for flash flooding could occur, especially across the eastern Ohio Valley on Wednesday. Meanwhile, to the north of the boundary, where temperature anomalies could be 5 to 10 degrees below normal, wintry precipitation returns from the Upper Midwest to New England. A few inches of snow could fall from northern Minnesota eastward to the Northern Great Lakes and northern New England with a light area of freezing rain possible near the rain/snow transition line from central Minnesota, across the Upper Midwest/Lower Great Lakes and into portions of upstate New York. Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php