Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 243 AM EST Sun Nov 20 2016 Valid 12Z Sun Nov 20 2016 - 12Z Tue Nov 22 2016 ...Colder temperatures arriving to the eastern U.S... ...More showers and mountain snow for the western states... Colder weather has made a quick return to much of the eastern U.S. following the passage of a strong cold front on Saturday. The days of Indian summer are over for now with cold northwesterly winds ushering in a cold airmass from Canada. Widespread highs in the 30s and 40s are forecast for many areas this weekend and lasting into early next week, and even some 20s are possible across the higher elevations of the Appalachians. Periods of lake effect snow are expected across parts of Michigan and upstate New York, resulting in the first noteworthy snow event of the season. Snow is also likely across the central Appalachians courtesy of upslope flow. Across the western U.S., another Pacific storm system is expected to bring more showers and mountain snow for this weekend. The heaviest precipitation should be from the Sierra Nevada to the Pacific Northwest coast, and lighter rain/snow across the Intermountain West. By the end of the forecast period on Tuesday morning, a new surface low is expected to develop over the central Plains and bring showers and thunderstorms from Missouri to Texas, and more wintry weather to the northern Plains. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php