By Steven Strouss

PHILADELPHIA (CBS) — With the arrival of freezing temperatures, the first flakes of the season may not be too far behind.

A Freeze warning goes into effect overnight for much of southeastern Pennsylvania, Interior New Jersey and Northern Delaware as temperatures tumble into the upper 20s and lower 30s. Widespread frost is likely by Wednesday morning and this will damage any sensitive plants that have not been protected.

A Frost advisory remains in effect from midnight until 9 a.m. for Philadelphia and the cold air could set the stage for a wintry mix of precipitation in the Poconos by Thursday morning.

The best chance of seeing snowflakes is north of I-78, early on Thursday, as a quick moving storm system pushes through eastern Pennsylvania. Some icy spots could develop on area roads and walkways before warmer air pushes in and change precipitation over to plain rain. Carbon and Monroe counties have the best chance of seeing snowflakes falling from the sky and there is also a possibility that some sleet or freezing rain mixes in before the changeover occurs.

This doesn’t produce much in the way of accumulation, but it is a sign that winter is coming.

Elsewhere, we are forecasting cool but dry conditions for Philadelphia and surrounding counties through tomorrow and just rain on Thursday as temperatures climb into the upper 50s. The weekend looks seasonable at this point with the possibility of more showers.