The National Weather Service in Cleveland's lake-effect snow warning for Erie County extends until Friday at 7 a.m. The weather service notes that travel could be difficult at times, and the Pennsylvania Department of Transportation has activated vehicle restrictions on interstates in northwestern Pennsylvania.

On Tuesday at 3:20 p.m. the National Weather Service issued a lake effect snow warning valid from Wednesday 4 p.m. until Thursday 4 p.m. for Northern Erie and Southern Erie.

Lake-effect snow occurs when the water temperatures of the lake are warmer than the air temperatures that blow above it, according to the National Weather Service.

A Lake Effect Snow Warning has been issued for parts of Western New York this Wednesday through Friday. Expect school closings and cancellations.

Erie County is under a disaster emergency, the city has enacted a snow emergency and PennDOT has restrictions on parts of interstates, 79, 90 and 86.

Ten inches to 18 inches of new snow could be headed for parts of Erie and Crawford counties during a new lake-effect warning starting Wednesday night.

The mid-December warmup is going to be short-lived. The National Weather Service in Buffalo has issued a Lake Effect Snow Warning for Jefferson, Lewis and Oswego counties starting at 7 p.m. Wednesday and lasting through 7 p.

A lake-effect snow warning remains in place for Erie County through Tuesday, and a lot more snow could fall across Erie County by then.

Northern Erie County is expected to receive 10-to-20 inches in the most persistent bands between Wednesday night and Friday early afternoon, the National Weather Service Buffalo said.

The National Weather Service has issued a lake effect snow warning for parts of the North Country. It will be in effect in Jefferson, Lewis and Oswego counties from 7 p.m. Wednesday to 7 p.m. Friday.