Tonight’s NAM has a QPF of 0.13 water falling as light snow Sunday evening ending before daybreak Monday. This translates into 1-2 inches.
High pressure builds in for Saturday and most of Sunday. As mentioned previously this week, the frontal boundary remains not far to our south. A disturbance will move along this front bringing light snow to our area Sunday evening and night.
Saturday will be sunny and cold. It will be windy with high temperatures 33-35. Clear and cold Saturday night.
Sunday will start sunny, but the aforementioned disturbance approaches Sunday and cloudiness will become significant by about noon. High temperatures near 38.
Light snow is expected Sunday evening and night. Currently, the GFS gives us a coating, the NAM and ECMWF about 1 inch, slightly more south of Philadelphia.
On the horizon is a more significant storm expected to move to our west on Tuesday and spawn a weaker coastal low off the New England coast.
Warm, moist air overspreading cold air at the surface will allow snow to develop Monday night but the snow will change to sleet and freezing rain Tuesday morning, likely early. Then all rain.
An extended period of freezing rain and sleet is possible in the northwest suburbs into Tuesday morning as a “cold air damming” effect occurs. A changeover to all rain will occur in all areas, but later further north.