Day 7: Southeast Surface Analsysis

Posted by pmarsh on 7 Jan 2010 | Comments Off

Well, in honor of Alabama’s victory in the BCS National Championship football game tonight, we’ll examine tonight’s surface analysis from the southeast United States.

The image above has been analyzed by various computer algorithms and computer models.  The solid lines are lines of constant pressure (isobars), the dashed lines are lines of constant temperature (isotherms), and the blue “H” in the bottom right is where one of the computer algorithms believes the center of a high pressure is located.  The numbers, circles, and barbs that are all over the map comprise what is known as a “station model“.  It is a pictograph of the surface weather conditions at the given location.  In the station model, the temperature is the red number, the dewpoint is the green number and the surface pressure (reduced to mean sea-level) is the black number.  The direction the wind is blowing from is indicated by the “stick” and the wind speed is indicated by the “barbs” on the stick.  (A half barb is 5 knots, a full barb is 10 knots, and a flag is 50 knots.)  Also, the “weather” symbol is located between the temperature and dewpoint and is light blue; the double stars means light snow (Atlanta and Nashville) and the double dots means light rain.

The image below has several features drawn in by myself.  The approximate location of the cold front is the thick blue line with triangles (known as barbs) drawn on it.  The thin blue line is the surface freezing line; the 10F contour is in the upper left (green) while the 50F contour (in Florida panhandle) is in red.  As you can see…the cold air is surging south and east!  It’s only a matter of time before it reaches Florida!

(Images courtesy of the Hoot Project, a division of the Oklahoma Weather Laboratory.)