Jun 7, 2012

"Wait and see" until Independence Day

The wet season is off to a pretty good start ...

But we won't know for sure until July 4th.

The above chart compares this year's "weekly interval" rain fall compared to the long-term, i.e. 20-year, record for all of south Florida.  The long-term median is plotted as a solid line and the long-term mean is plotted as a dotted line.  Memorial Day roughly corresponds with the typical start up of wet season rains.  This year, the wet season got an early head start by way of some timely (and abundant) late spring rains.  Can you also see how the first part of the wet season, from Memorial Day to the Fourth of July, is the rainiest.  The lull in rains between July and August is a result of the vertically stable winds of the Bermuda High setting in.

That's because for south Florida the 4-5 week period between Memorial Day and the Fourth of July is usually the rainiest. The reason? At first glance one might assume that rainier conditions would prevail later in the summer (and early fall) when the tropical storm systems get going in full force. But it's the early wet season's lingering instability in the upper layers of the atmosphere (i.e. as the northern hemisphere transitions from winter to summer mode) that stokes the meteorologic flames on Florida's famed sea-breeze fed storms.

Meteorologists in West Palm call it the "Enhanced Sea Breeze" effect.


That lingering instability can also bring some extratropical storms, too.

(That's just a fancy term for a mid-latitudinal cyclone.) At some point in the wet season we wait in baited breath for a windless tropical system to save the day (i.e. rain but no wind). But before we get that far ahead of ourselves let's check back in on this on July 4th.

You can't stop the wet season now.
As seen June 2009

My prediction:

Regardless the rain amount,
we'll all be celebrating with a big parade.

1 comment:

Suwannee Refugee said...

Man, ya'll have gotten tons of rain in South Florida so far this year. Based on what I'm hearing ya'll are doing just fine;)