Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 248 AM EST Thu Jan 08 2015 Valid 12Z Thu Jan 08 2015 - 12Z Sat Jan 10 2015 ...Temperatures will be 20 to 25 degrees below average from the Tennessee Valley to the Mid-Atlantic... ...Heavy lake effect snow will develop downwind from the Great Lakes... Cold high pressure over the Southern Plains to the Tennessee Valley will move eastward off the Southeast Coast by Friday morning. A second cold high pressure center over West-Central Canada will move southeastward to the Central/Southern Plains by Friday evening. Upslope flow associated with the circulation around the second high pressure will aid in producing light snow over parts of the Northern High Plains that will move to the Central High Plains by Friday morning before ending by Friday afternoon. Meanwhile, cold air moving over the Great Lakes and upper-level energy will aid in producing lake effect snow downwind from the Great Lakes on Thursday morning. A developing clipper system will move eastward from the Northern Plains to the Great Lakes by early Friday morning and then northeastward to Eastern Canada by Friday evening. The associated cold front will move eastward and off the East Coast by Friday afternoon. The system will produce light snow over parts of the Upper Mississippi Valley on Thursday morning and lake enhanced snow over the Great Lakes Thursday afternoon through Friday morning. Snow will be heavy downwind from the Great Lakes Friday morning into Friday evening. Moisture trying to move northward from the Western Gulf of Mexico will produce areas of rain/freezing rain over parts of Southwest Texas on Thursday morning. The moisture will continue to move northward and produce light rain over parts of Southern Texas and the Southwest Thursday evening into Friday morning. The rain will be restricted to Southern Texas by Friday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php