NORFOLK, Va. (AP) — A developing winter storm threatens to drop snow, sleet and freezing rain on parts of Texas, Oklahoma and Arkansas as frigid air that escaped the Arctic plunges temperatures to subfreezing levels in some of the southernmost points of the U.S.

Storm Blair has hit most of the U.S., bringing freezing temperatures to Texas. Precipitation later this week could mean snow for some areas.

Our chilly weather could bring freezing rain and snow to parts of the Hill Country and I-35 corridor, local forecasters say. Why it matters: A polar vortex hauling arctic air from Canada down across the U.