A major winter storm will generate impressive snow totals today and tonight, before tapering off on Wednesday. Widespread heavy snow across northwest Colorado will spread southward this afternoon and impact the Interstate 70 corridor. Tonight, the heavy snow band will sweep toward southwest Colorado before departing Wednesday afternoon. Lesser snow accumulations are expected across eastern Utah. On Wednesday night, temperatures will plummet at sunset with the coldest night thus far this winter season expected on Thursday morning. The coldest mountain valleys could observe morning lows of 25 below zero.   (Please visit http://weather.gov/gjt for more information.)