The National Weather Service has updated the snow amounts expected. Forecasts are calling for 16 to 24 inches of snow before the storm ends Tuesday morning.

Due to the severity of the winter storm, PennDOT has restricted speeds to 45 mph and commercial vehicles must move to the right lane on the following roadways:

• Route 22 in Lehigh and Northampton counties:

• Route 33 in Monroe and Northampton counties;

• Interstate 78 in Berks, Lehigh and Northampton counties;

• Interstate 80 in Carbon and Monroe counties;

• Interstate 380 in Monroe County.

The following vehicles are not permitted on these roads:

• Passenger vehicles (cars, SUV’s, pickup trucks, etc.) towing trailers.

• Tractors without trailers.

• Tractors towing unloaded or lightly loaded enclosed trailers, open trailers or tank trailers.

• Tractors towing unloaded or lightly loaded tandem trailers.

• Recreational vehicles/motor homes.

• School buses, commercial buses and motor coaches not carrying chains or Alternate Traction Devices; and motorcycles.

Restrictions will be communicated via variable message boards, the 511PA traveler information website at www.511pa.com and smartphone apps. Motorists can also sign up for alerts on www.511pa.com by clicking on “Personal Alerts” in the left-hand menu.

Although PennDOT crews are treating roadways, the department’s primary goal is to keep roads passable, not completely free of ice and snow. PennDOT will continue to treat roadways throughout the storm until precipitation stops and roads are clear.

While PennDOT recommends not traveling during winter storms, motorists can check conditions on more than 40,000 roadway miles, including color-coded winter conditions on 2,900 miles, by visiting www.511PA.com. 511PA, which is free and available 24 hours a day, provides traffic delay warnings, weather forecasts, traffic speed information and access to more than 1,000 traffic cameras.