The weather wire is buzzing today because of the unusually cold upper air temperatures over the northeast. From Chicago to Quebec City, the temperature this morning at 500mb (or around 18,000 feet) was -30C (-22F). The strong sun now heats up the surface air easily past 60F. This warm air rises into much colder air aloft, building clouds and generating showers and thunderstorms. This is why today started sunny but now it's cloudy--once the burner was turned on, that's when the process began.

Tonight will clear out. When the sun goes down, the burner turns off, the clouds dissipate, and it will just be a little chilly.