Effects of Radiational Cooling and Temperatures

[Stormsfury]

Notice on the temperature maps from 6 am this morning with light winds, and clear skies, just how cool it got into the Southeast this morning. The freeze warning for the South Carolina coast verified quite nicely as the temperatures fell into the upper 20's this morning ...

[Lowpressure]

Agreed, we were well on or way into the twenties until the cloud deck thickened, I had 32 at my house for a long time. Never saw the twenties last night.

[WXBUFFJIM]

Temps were held up into the mid 30s this morning here near the Chesapeake Bay in Baltimore. Skies initially were partly cloudy. But the winds were up also. That mixing component combined with the thick high level cloud deck early this morning, and temperatures were held up due to that. Any flurries never made it to the ground because at the surface, it was very dry. So it wasn't much luck.

Meanwhile with high pressure centered over the southeastern US, the stage was more set there for even colder temperatures because with high pressure the air sinks, compresses. Thus no clouds form and the winds are quite calm. Very dry air also. Certainly an interesting night last night given that the southeast was colder than even areas north of there.

Jim

[Stormsfury]

Meanwhile with high pressure centered over the southeastern US, the stage was more set there for even colder temperatures because with high pressure the air sinks, compresses. Thus no clouds form and the winds are quite calm. Very dry air also. Certainly an interesting night last night given that the southeast was colder than even areas north of there.

Because of the light winds/calm winds and clear skies, any surface heating was rapidly advected from the surface. Ideal radiational cooling took place with no means to trap the afternoon heating (relative - 55º isn't exactly warm) ..

On the other hand, temperatures have rebounded quite nicely this afternoon with maximum insolation and neutral air advection (no CAA or WAA).

[ColdFront77]

Meanwhile with high pressure centered over the southeastern US, the stage was more set there for even colder temperatures because with high pressure the air sinks, compresses. Thus no clouds form and the winds are quite calm. Very dry air also. Certainly an interesting night last night given that the southeast was colder than even areas north of there.

The temperature was 20 to 25 degrees colder here in central Florida
than it was in eastern Massachusetts the night before last!