By Justin Drabick

A large area of high pressure is situated over the Delaware Valley keeping the forecast dry, but it has brought a brief surge of cold air.

Classic radiational cooling conditions occurred last night with the high pressure system in place. The clear skies with calmer winds allowed the day time heat to radiate back into the atmosphere. This allows the cold dense air to settle down at the surface.

Low temperatures were below average Sunday morning as the coldest air since March came in. Another cold night in the 20s expected tonight but temperatures slowly moderate through the week.

Check out Sunday morning’s low temperatures:

Mt. Pocono, PA: 13
Allentown, PA: 20
Reading, PA: 21
Atlantic City, NJ: 23
Trenton, NJ: 23
Wilmington, DE: 23
Philadelphia, PA: 28

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