Bath, Pennsylvania - U.S.A.

Charles A. Giannetta

Meteorologist

Professor

Above map provided by the: "National Weather Service"


"Surface Analysis & 1000-500 mb thickness chart"

1...Red dashed lines indicate temperatures above 32 degrees on the 1000-500mb analysis.

2...Blue dashed lines indicate temperatures below 32 degress on the 1000-500mb analysis.

3...Black lines are isobars on the surface map.

4...The THICKNESS" is the difference betweeen two pressure level charts. In the above map the difference between
....the 1000mb and 500 mb pressure charts.

5. Rain and snow can occur when the 500-1000 thickness is about 5225. Rain is rare when the 500-1000 thickness is less than 5190.
....Snow is less likely to occure when the 500-1000 thickness is greater than 5395.

6...The 1000-500mp is measures in "Dacameters. (Dm)" A Dacameter is a unit of length equal to 10 meters.

7...Warm air is less dense and takes more space causing a taller (thicker) atmosphere.

8...Cooler air is more dense so it takes up less space. The result is a shorter (less thick) atmosphere.

9...The higher the thickness usually means a warmer atmosphere.

10..The lower the thicknes results in a cooler atmosphere.

11..Air with a thickness below 540 Dm is cold enough to support snow.

12..Air above 540 Dm thickness is not. This is not always true.

© 2013 Charles A. Giannetta

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