Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 346 AM EST Fri Jan 23 2015 Valid 12Z Fri Jan 23 2015 - 12Z Sun Jan 25 2015 ...Coastal storm to spread heavy rain to the Southeast while a wintry mix is expected over the Mid-Atlantic/Northeastern U.S... ...Well above normal temperatures in the forecast for the center of the country... A deep upper trough currently swinging through the Southern Plains will continue to have access to abundant moisture from the Gulf of Mexico. This will make the advancing system quite the precipitation maker as it gradually lifts up the Eastern Seaboard. As the associated area of low pressure lifts through the Carolinas late Friday night, continued intensification is expected which will begin to increase the wind field around the system. A fairly healthy swath of rainfall is forecast to stretch from the eastern Gulf Coast up along a majority of the East Coast. 1 to 2 inches of rainfall should be expected through Sunday morning. Meanwhile, enough cold air wrapping around on the back side of this system should spread measurable snows from the Central Appalachians up across sections of the Mid-Atlantic and into coastal New England. Additionally, along the rain/snow line will be a mixture of precipitation types which may include freezing rain and sleet. All and all, this should not be a major snow producer given the lack of a surface high to the north which would bring a continual supply of cold air into the regions precipitating. The intrusion of maritime air into the mix will make this an event consisting of multiple precipitation types. The story across a large section of the Central U.S. will be the above normal temperatures. Downsloping winds in the lee of the Rockies will aid in sufficient warming throughout the day with high temperatures approximately 15 to 20 degrees above normal across the Northern Rockies and into the Northern/Central Plains. Such anomalies will even be more impressive overnight reaching possibly 25 to 30 degrees above climatology. This would place Sunday morning temperatures in the 30s which is rather mild for late January. Elsewhere, a fairly strong clipper system will work its way down from Alberta into the Upper Midwest by Saturday night. This feature should begin to spread light/moderate snow across Minnesota and Wisconsin early Sunday with 2 to 4 inches possible. In spite of a limited moisture source, clipper systems can easily produce localized higher amounts where mesoscale banding occurs. Quasi-zonal flow across the Pacific Northwest is forecast to be in place with a tremendous feed of moisture across the Eastern Pacific. The combination of onshore flow with upslope trajectories along the terrain will lead to hefty precipitation amounts over areas of the Olympics and Washington Cascades. Some of this activity should migrate inland affecting areas of northern Idaho and northwestern Montana. The mild nature of these Pacific air masses will keep snow levels rather high throughout the event. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php