Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 244 PM EST Thu Dec 04 2014 Valid 00Z Fri Dec 05 2014 - 00Z Sun Dec 07 2014 ...Mix of snow, sleet, and freezing rain expected across the Northeast... ...Freezing rain possible for interior portions of the Pacific Northwest... A low pressure system is forecast to develop across the southern plains tonight as an upper-level disturbance encounters a surface frontal boundary. Showers and thunderstorms will spread across the southern/central plains tonight and into the Ohio valley and Lower Great Lakes during the day on Friday ahead of this low pressure system. As precipitation becomes more widespread across the Northeast late Friday and into Saturday, a wintry mix of precipitation is expected, with snow forecast for northern New England, and a mix of sleet and freezing rain possible from northern Pennsylvania into southern New England. An Arctic frontal boundary remains firmly entrenched at the surface across the Pacific Northwest and northern Intermountain West. Moisture lifting across this frontal boundary will result in scattered precipitation across the Northwest. Shallow cold air trapped in the Columbia Basin will result in the potential for freezing rain through tonight. Another Pacific storm system will approach the West Coast on Friday, with precipitation gradually increasing in coverage across the West Coast states on Friday. Rain and high elevation snow will persist in to Friday night before beginning to taper off on Saturday as the front weakens and moves inland. From the Rockies across the plains to the southeastern states, temperatures will remain near or above average through Saturday, before a cold front sweeps southward bringing cooler air to much of the central U.S. for Sunday. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php