Nov 13, 2012

Out of sight (but in mind)

What's in store for the upcoming dry season?

Answer: Maybe the El Niño Southern Oscillation Index holds a clue.

This bar chart highlights the influence of warming (or cooling) in the equatorial Pacific on winter rainfall amounts in south Florida.  El Niños (red) tend to coorelate with wetter-than-normal rains in the Everglades and La Niñas (blue) tend to correlate to dryer-than-normal winters.  Such far ranging meteorological cause-effect relationships are often called teleconnections.  

At the whimsy of its swing, so goes the abundance (or absence) of south Florida's winter rains.

Caveat: Abundance is a relative term.  South Florida's long-term winter rain average -- as counted from November through April -- is just 14 inches.  Compare that to a 38-inch average for the 6-month summer half of the year (May through October).  La Niña's prevailed the last two winters. That brought us deep drought two springs ago and the threat of a repeat last year.  Timely April rains saved the day.  This year is edging towards an El Niño instead, but not a high amplitude one just yet.


As it stands today, all talk is speculative:

We're still waiting for our first dry season storm.

No comments: