WRUF Weather

10 Day: Rainy Season Ends This Week

We talked about four criteria that typically make up the rainy season in North-Central Florida back in May.  A change in the weather pattern this week is prompting us to take a look at those same criteria, concluding that the “rainy season” is just about over.  Here’s a breakdown on those four factors that typically give us showers and thunderstorms each afternoon:

Air Temperatures Near 90:  Inland temperatures this warm are usually required to create the difference necessary for a sea breeze to develop and lift the air as it advances inland.  This rising air causes showers and thunderstorms to form.  While temperatures this week will remain warm enough to induce a sea breeze, the slightly cooler air will lead to less instability and rising air, which is key to thunderstorm growth.

 

Dew Points:  Moisture in the atmosphere is typically measured by the point at which condensation occurs, or the dew point.  When these values are near or above 70, the processes for rain to develop are much more efficient.  Dew points for much of the summer have been in the 70s, but they are forecast to drop nearly 10 degrees this week.

 

Wind Direction:  Dominant winds over the summer are usually out of the southwest or southeast, both coming off of large bodies of water.  Winds out of the Gulf of Mexico usually bring unsettled weather in the form of strong thunderstorms and heavy rain.  Winds off of the Atlantic can bring deeper moisture from the tropics, sometimes aided by tropical storms or hurricanes.

 

Water Temperatures:  Water temperatures above 80 usually promote greater moisture transport into the state, especially when tropical trade-winds develop.  This is the least-important factor in classifying rainy season conditions.

 

 

It’s important to note that just because the official rainy season may be over, periods of showers or thunderstorms will still be possible over the coming months.  The only difference is that they will typically be driven by frontal passages or areas of low pressure coming out of the Gulf, rather than sea breezes and daytime heating.  It is also possible that a tropical storm or hurricane could still impact the state, as the 2012 Atlantic Hurricane Season doesn’t officially end until late November.


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