Archive for January 1st, 2009|Daily archive page



What a terrific way to start the new year in this weblog – with an image of nearly the whole earth showing cloud patterns over both the daylight half and the darkness half.  The two rows of extratropical cyclones (one over the middle latitudes of each hemisphere) are striking.  Since a very high percentage of the over 6.7 billion people on earth live in the middle latitudes, and since these cyclonic systems and their cold fronts commonly extend into the lower latitudes, you might very well be under the influence of one of these systems this very moment.  They are marching generally from west to east in both hemispheres followed by cold (or cooler) anticyclones.  For example, I live in the low latitudes at 28.972 degrees north and we get several frontal passages.

The Intertropical Convergence Zone is apparent, especially over Africa.  Notice how it is further south now over that continent than during the North Atlantic hurricane season.

HERE’S WISHING YOU ALL A HAPPY NEW YEAR.  That’s just the beginning because my wishes for you are many.  That:  You “know” love and feel both loved and lovable, you are never bored, you have a long gratitude list, happiness is not illusive, you feel as good as possible for your circumstances, life’s pros far outweigh the cons, and you experience peace and good will always.

Tonie A. Toney (Cloudman23)

=     =     =     =     =     =     =     =     =     =     =     =     =     =

NOTES:  Extratropical means “outside of the tropics.”

Middle latitudes are strictly defined as the regions between 30 degrees and 60 degrees latitude (both hemispheres).

Extratropical cyclones differ from tropical cyclones in the following ways.  ET cyclones are “cold core” lows while T cyclones are “warm core” lows.  ET cyclones generally have fronts associated with them, T cyclones do not.  ET cyclones originate mostly in the middle latitudes while T cyclones originate in the low latitudes (0 degrees to 30 degrees).  ET cyclones are asymetrical with decided wind direction changes and measurable temperature changes on either side of the fronts, while T cyclones are more nearly circular.

The Intertropical Convergence Zone is where the Northeast Trades and the Southeast Trades converge.  Years ago it was referred to as the Doldrums and also the Equatorial Low.  Those two outdated terms are still found in the literature and even on line.  Generally, the ITCZ migrates northward during the northern hemisphere warm season and southward during the northern hemisphere cold season.