National Weather Service Threat Map

The National Weather Service indicates the possible impacts from a coastal storm expected to pass Delaware on Sunday night, January 16, 2022. (Issued January 13)

Forecasters are becoming more certain a strong coastal storm will affect Delaware late this weekend, but there still remains plenty of doubt over the type, or types, of precipitation that will fall from the sky.

The National Weather Service is expecting a low pressure system to form in the southeast, and eventually work its way towards the north or northeast.

That pathway will prove crucial, because the further west it goes, the better chance it has to bring warm air from the south on its counterclockwise flow, despite Saturday night's low temperature projected to be 11 degrees in Wilmington.

As of Thursday night, NWS projections have the storm roughly paralleling I-95, which would be close enough for most of Delaware, especially northern sections, to start as snow, before a potentially quick changeover rain.

If the storm tracks closer to the Appalachian Mountains than currently forecast, the changeover would happen quicker, but if it were to stay just off the coast, it might happen later, or not at all.

Those stark differences could come with less than 50 miles in either direction from current track.

NWS forecasters are not projecting amounts for the storm at this point, but over an inch of overall liquid from the storm is possible. A winter weather outlook puts extreme northwest Delaware, north of I-95, in about a 50% range for 2+ inches of snow. The percentages drop to 30-50% for the rest of New Castle County and Kent County, while it falls to 10-30% in Sussex County.

Whether the storm is snow, sleet, or rain, winds from the east are expected to pick up, with the NWS hinting a wind advisory may be needed for the beaches.

That precipitation is expected to begin late afternoon or into Saturday evening, with a focus on the overnight hours into early Monday morning before things improve.

Tuesday is expected to be in the high-30s, before potentially a seasonable mid-40s day on Wednesday.