Severe weather threat returns to the northern and central Plains onTuesday, followed by severe weather and heavy rain/flash flooding threatsfarther down the central Plains on Wednesday......More high-elevation snows expected across the Pacific Northwest intothe northern and central Rockies for the next couple of days......Warmer than average temperatures across the southern tier states to theMidwest and Mid-Atlantic but cold and windy across the Northwest...The weather pattern that keeps send...