Snow will be prelude to messy weekend winter storm, flash freeze: What you need to know about the Philly-area forecast

Clouds are moving into the Philadelphia area on the heels of a cold front that will keep temperatures around the freezing mark Thursday. Light snow is expected to start falling during the night, mainly after 11 p.m., and end before the morning commute Friday, according to the National Weather Service. The service’s latest projections call for no accumulation along the coast, less than an inch in South and Central Jersey and an inch in Eastern Pennsylvania, with up to two inches in western Chester County and the Poconos. The weather service says the Friday morning commute could be affected in areas where the snow has accumulated the most.

Forecasters are tracking a moisture-rich winter storm that is expected to arrive Saturday and linger into Sunday before an arctic blast sends temperatures diving.

The storm’s progress looks like this in the current forecast: There’s a chance of rain and snow showers before 1 p.m. Saturday with rain likely after that before changing to rain and snow showers after 5 p.m. After 8 p.m., the storm is expected to turn back to rain only until noon Sunday, when it will flip back to rain and snow and then snow in the afternoon.

Once the storm moves away, temperatures will plunge from a projected high of 41 degrees in Philadelphia into the teens and single digits later Sunday into Monday morning. The freeze is expected to turn all the weekend moisture into ice, impacting Monday’s morning rush hour. “Prepare now (!) for several days of dangerous cold, large icy patches on roads,” the weather service said in its forecast discussion Thursday morning.

Besides the ice, the main concern for Monday — which also is the Martin Luther King Jr. Day holiday — is that it will be dangerously cold. The projected high for the day is only 15 degrees and wind chill values could be as low as 10 below zero in the morning. The skies will be sunny during the day.