Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 236 AM EST Wed Jan 07 2015 Valid 12Z Wed Jan 07 2015 - 12Z Fri Jan 09 2015 ...Lake effect snow for the Great Lakes... ...Temperatures will be 20 to 30 degrees below average for parts of the Plains, Mississippi Valley, and Ohio Valley... Cold high pressure over the Northern Plains will move southeastward to the Southeast by Thursday evening. A second cold pressure center over Northwest Canada will sink southward east of the Canadian Rockies to the Northern High Plains by Thursday evening, too. Cold air moving over the Great Lakes and some upper-level energy will aid in producing lake effect snow downwind from the Great Lakes and over parts of the Northern/Central Appalachians through Thursday morning. Upper-level energy rotating out of West-Central Canada will induce a wave of low pressure over parts of the Central High Plains late Wednesday night. The clipper system will move to the Upper Great Lakes by Thursday evening. The system will produce light snow over parts of the Northern Plains on Thursday morning and lake enhanced snow over the Great Lakes by Thursday evening. Upslope flow will aid in producing an area of snow and sleet/rain/freezing rain over parts of the Central/Southern High Plains on Wednesday morning, ending by Wednesday afternoon. Similarly, flow off the Western Gulf of Mexico will aid in producing light rain over parts of Southern Texas Wednesday evening into Thursday morning. In addition, upslope flow associated with the second area of high pressure will produce snow over parts of the Northern/Central High Plains on Thursday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php