Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 254 AM EST Wed Dec 11 2019 Valid 12Z Wed Dec 11 2019 - 12Z Fri Dec 13 2019 ...Heavy snow for the mountains of the Pacific Northwest and Northern/Central Rockies... ...Light to moderate snow over the Upper Great Lakes... ...Temperatures will be 10 to 25 degrees below average over the Upper Midwest... ...Wind chill advisories for parts of the Upper Midwest... Rain changing over to snow over the I-95 corridor on Wednesday morning will cause travel concerns. The snow will taper off over the Northern Mid-Atlantic/Northeast by Wednesday evening. A weak system over the Great Lakes will move eastward off the Northeast Coast by Thursday. The system will produce snow and lake enhanced snow over the Great Lakes that will move into the Lower Great Lakes by Wednesday evening. The will snow dissipate over New England by Thursday afternoon. Meanwhile, a wave of low pressure will develop over parts of the Northern High Plains that will move eastward into the Great Lakes overnight Thursday, moving into parts of Canada by Friday morning. Snow will develop over parts of the Northern High Plains on Wednesday evening moving into the Upper Mississippi Valley/Upper Great Lakes by Thursday morning. The snow will continue over the Upper Great Lakes through Friday morning. In addition, upper-level energy over California will move eastward to the Tennessee Valley by Friday. Ahead of the energy, moisture from the Gulf of Mexico and Atlantic will move over the Southeast on Wednesday evening and continue northward into the Northern Mid-Atlantic and the Ohio/Tennessee Valleys by Friday. Rain will develop over parts of the Southeast overnight Thursday expanding northward into the Tennessee Valley/Mid-Atlantic by Friday. As the moisture moves northward an area of rain/freezing rain will develop over parts of the Central/Southern Appalachians overnight Thursday into Friday. Elsewhere, energy moving onshore over the West Coast will move inland to the Great Lakes/Tennessee Valley by Friday. The energy will be followed by more weak upper-level energy over the West through Friday. Onshore flow will aid in producing rain and higher elevation snow over the Pacific Northwest and Northern/Central California on Wednesday into Friday. Scattered snow will develop over parts of the Northern/Central Rockies on Wednesday evening into Friday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php