Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 342 PM EDT Sat Sep 12 2015 Valid 00Z Sun Sep 13 2015 - 00Z Tue Sep 15 2015 ...Heavy rain possible tonight for portions of the Northeast... ...Severe thunderstorms possible for portions of the Florida Peninsula... A strong early fall-like cold front will move across the East Coast states tonight, bring rain and thunderstorms from Florida to New England. A surface low across the Lower Great Lakes and a warm front south of New England will result in an area of widespread rain and thunderstorms across portions of the Northeast tonight, which will persist into Sunday as the upper-level low moves across the region. Rain will linger the longest across far northern New England, where showers may linger into Monday morning. Heavy rain will be possible, with rainfall totals tonight into Sunday surpassing one inch for portions of Upstate New York. Farther south, an unstable air mass across the Florida Peninsula combined with sufficient wind shear along the cold front will result in the potential for some thunderstorms to become severe -- and the Storm Prediction Center is forecasting a slight risk of severe thunderstorms across portions of the Florida Peninsula through tonight. Behind the front a Canadian air mass with fall-like temperatures will overspread the eastern U.S. Afternoon high temperatures on Sunday will be 5 to 15 degrees below average across much of the eastern half of the country. Temperatures will moderate some by Monday, but are still forecast to remain below average. A largely dry cold front will move into the northwestern U.S. early Sunday morning. A few scattered thunderstorms are possible Sunday afternoon across the northern Intermountain West, but most areas will remain dry. The front will become stationary and linger across the northern Intermountain states on Monday. Moisture will begin to increase across the West ahead of another incoming Pacific upper-level disturbance, so scattered showers and thunderstorms appear possible over a wider area on Monday. North of the front, cooler temperatures will move into the Pacific Northwest, with high temperatures on Monday 5 to 10 degrees below average. Elsewhere temperatures will remain above average across most of the Intermountain West. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php