Weather

Much of the eastern two-thirds of the United States will remain in the grip of an arctic air mass Tuesday. A large southern dip in the jet stream will continue, with a high-pressure system near Missouri and Illinois. Conditions east of the Rockies may continue to be colder than any point last winter.

A flow of air from the Gulf of Mexico and a developing storm will bring clouds and rain to Central and South Florida. The storm is projected to strengthen as it tracks north later this week, just offshore. The storm track’s proximity to the coast will determine how much snow extends west over the Middle Atlantic and interior New England. The storm is also expected to bring blizzard conditions to parts of eastern New England. Lake-effect snow should ease midweek.

In the western third of the nation, milder weather is in the forecast. Most areas can expect at least partial sunshine. Enough moisture may arrive from the Pacific to result in clouds and a few showers. Much of California will turn more humid later in the week. Parts of Southern California may experience the region’s first rainfall in months.

Snow and strong winds will affect the Middle Atlantic coast and New England on Thursday and Friday. The storm may bring blizzard conditions to much of Maine and eastern Canada. A harsh arctic cold spell will follow the storm throughout the East.