CHICAGO, Jan 21 - U.S. housing starts probably slipped in December, hurt by wintry weather and backtracking after three months of gains that carried starts to the highest level in almost 20 years. Economists surveyed by pegged starts at a median of 1.96 million units, down from 2.07 million in November. The 26 estimates ranged from 1.875 million to 2.07 million units. Building permits were forecast at 1.860 million units, versus 1.863 million in November, in a range of 1.820 million to 1.960 million units. Ground-breaking on projects in the Northeast was delayed by a series of snowstorms, reversing the benign weather trend that helped boost November starts. Interest rates on home mortgages have risen from the historical lows touched in late spring but remain low enough to keep most buyers interested. Rising consumer confidence has also encouraged big-ticket purchases such as real estate. The National Association of Home Builders' housing market index for January, a measure of builder sentiment, slipped to 68 from 70, the group said on Tuesday. Foot-traffic from would-be buyers also declined. The December housing starts and building permits reports are scheduled for release by the U.S. Commerce Department at 8:30 a.m. EST (1330 GMT) on Wednesday.//