The National Weather Service has issued a winter weather advisory from 1 a.m. to 4 p.m. Saturday.

Snow accumulations of 2 to 4 inches are expected and can cause slippery road conditions.

Here is the latest forecast:

This Afternoon: Mostly sunny, with a high near 33. Southwest wind around 10 mph.

Tonight: A chance of snow, mainly before 4 a.m. Increasing clouds, with a low around 25. South wind around 5 mph. Chance of precipitation is 50%. New snow accumulation of less than one inch possible.

Saturday: Snow, mainly before 2 p.m. The snow could be heavy at times. High near 37. Southwest wind 5 to 10 mph. Chance of precipitation is 80%. New snow accumulation of 2 to 4 inches possible.

Saturday Night: A slight chance of snow after 1 a.m. Mostly cloudy, with a low around 25. Southwest wind around 5 mph becoming calm. Chance of precipitation is 20%.

Sunday: A chance of snow, mainly before 1 p.m. Mostly cloudy, with a high near 32. Calm wind becoming west around 5 mph in the morning. Chance of precipitation is 30%. Little or no snow accumulation expected.

Sunday Night: Partly cloudy, with a low around 15.

M.L. King Day: Mostly sunny, with a high near 31.

Monday Night: Mostly clear, with a low around 7.

Tuesday: Sunny, with a high near 18.

Tuesday Night: Mostly clear, with a low around 7.

Wednesday: Partly sunny, with a high near 29.

Wednesday Night: Mostly cloudy, with a low around 20.

Thursday: Mostly cloudy, with a high near 36.

PennDOT is urging drivers to use cation and warning about snow squalls, which can be a brief and intense period of heavy snow (up to 2 inches in 30 minutes), strong winds (30+ mph), and whiteout conditions (visibility less than ¼ mile). Due to their isolated and intense nature, snow squalls can catch drivers off guard and lead to major transportation impacts, including multi-vehicle crashes.

While avoiding or delaying unnecessary travel during winter weather is the safest choice, PennDOT offers this advice if motorists must travel and encounter snow squalls or blowing or drifting snow:

• Slow down gradually and drive at a speed that suits conditions.

• Turn on your headlights. If caught in a snow squall, turn on your hazard lights.

• Stay in your lane and increase your following distance.

• Stay alert, keep looking as far ahead as possible and be patient.

• Use your defroster and wipers.

• Keep windows and mirrors free of snow and ice.

• During whiteouts, come to a complete stop only when you can safely pull off the roadway.

• Do not stop in the flow of traffic since this could cause a chain-reaction collision.

• Do not pass a vehicle moving slowly or speed up to get away from a vehicle that is following too closely.