Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 AM EST Mon Dec 28 2015 Valid 12Z Mon Dec 28 2015 - 12Z Wed Dec 30 2015 ...There is a slight risk of severe thunderstorms for parts of the Western Gulf Coast northward to west Tennessee... ...Heavy snow possible from portions of the Central Plains to the Upper Great Lakes... ...There is a chance of rain/freezing rain from parts of the Southern Plains into the Great Lakes and the Northeast... ...Heavy rain possible parts of the Middle/Lower Mississippi Valley and parts of the Southeast/Southern Appalachians... The robust storm system that has wreaked havoc across much of the southern and central states will move northward, reaching the Great Lakes region by Tuesday/early Wednesday. Snow will taper off across portions of Texas and Oklahoma by this afternoon and across eastern Kansas and northwest Missouri by this evening. The heaviest snow, (possibly mixed with sleet) will fall over Iowa, southern Minnesota, Wisconsin and northern Michigan today and into Tuesday morning. 6 to 10 inches will be common, with isolated areas nearing 15 inches. Numerous Winter Storm Warnings and Advisories are in effect from the Plains to the Upper Midwest/Great Lakes. Showers and thunderstorms will develop along and ahead of the advancing cold front over the south-central and southeast states. Conditions will be favorable for severe thunderstorms to develop today and the Storm Prediction Center has highlighted portions of Alabama, Mississippi, Tennessee and Florida with a slight risk. Please refer to the SPC webpage for additional information. Heavy rain will continue across an expansive area from the Gulf coast north to the Ohio Valley and the Ozarks to the Appalachians. Many locations are already water-logged and additional rain will cause further adverse impacts. Flash flooding will likely occur. Additionally, Monday evening into Tuesday morning, rain/freezing rain will develop over parts of Northern Appalachians and parts of the Northeast. Snow will develop over parts of the Northeast this evening and continue into Tuesday. Most of the Northeast have Winter Storm Advisories and watches in effect. 2 to 6 inches will be common, with New Hampshire and Maine expecting anywhere from 8 to 18 inches by Wednesday. Meanwhile, a dissipating front and associated deep upper-level trough will move into the Northwest today. The deep upper-level trough will move to the Southwest by Tuesday. Coastal rain and higher elevation snow is expected over the Pacific Northwest into Northern California, with the snow extending as far inland as parts of the Great Basin/Northern Intermountain Region. As the trough moves inland the snow levels over Northern California will lower today. The rain will move into Central/Southern California by this afternoon as snow develops over the Sierras. Snow will also move into parts of the Northern Rockies through Tuesday morning. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php