The Seabreeze Front

A calm “Ahhhhh” as the salty gulf air hits your face.  The sun shining brightly as the kids play in the waves at the beach.  Life is good.  That is, until about 2:00pm when clouds begin to darken to the north.  Flashes of distant lighting and low rumbles of thunder fill the air.  What the heck?  No one said anything about rain!!  Well, chances were good that they did, but you learned to ignore the mention of rain when the chances dropped to 20%.  In all likelihood, however, it will not rain at the beach, but Houston will get dumped on by the bucket full.  All thanks to the small-scale weather phenomenon called the “Sea-breeze Front”.

  A “Front” is nothing more than a separation between two different types of air mass.  For example, a “Cold Front” is a boundary that separates cold air from the warmer air ahead of it.  A “Warm Front” is a boundary that separates warm air from cooler air ahead of it.  The front is always named by the air mass type that pushing the front along.  So, a Sea-breeze Front is, well, a boundary and it definitely separates two different air masses, but nothing defines the temperature of it.  All we know is that the breeze from the Gulf gives it its name. Hint: Air from the sea, in the summertime, is cooler than the air over the land.  That’s because water takes longer to heat than land does.  So, technically, the Sea-breeze Front is actually a miniature cold front.  Except, the air isn’t “cold” by human comfort standards, but the breeze sure feels nicer than the stickier, more humid, air hovering over Houston.  That much we know.  Interestingly, it is the slight difference in temperature between the air over the city and the air over the water that gives the Sea-breeze Front its momentum and, ultimately, what causes the afternoon thunderstorms to form.

As the sun begins to heat the land, an air temperature difference is established between the cool moist air over the water and the warm, sometimes hot, drier air over the land. (Click image to make larger)

Because cooler air is more dense than warm air, it sinks, while the warmer air begins to rise.  The sinking air over the water forms a “local” or small-scale high pressure and a low pressure forms over the land due to the rising air.

Now that a pressure difference is established, the air over the water acts to balance out the system and begins to “fill in” the air over the land that has risen into the atmosphere.  Think of when you’re taking a very hot shower. The steam is rising and if you crack the door or slightly peel back the curtain, you can feel the cooler air rushing in to fill-in the void of air in a sense.  This pressure difference is what initiates the breeze we feel and begins the formation of the sea-breeze front.

Then as the moist air from the gulf is lifted up, clouds form. Usually nice puffy cumulus clouds at first, but as this process continues it can lead to some very intense summer thunderstorms with heavy rain and flash flooding.

This phenomenon does not occur everyday during the summer.  There still has to be a friendly upper level environment that would promote thunderstorm formation.  Take last summer for example.  The summer-long high pressure put a lid on any possible thunderstorm formation along the sea-breeze.  So, storms are not a guarantee with the sea-breeze front, but it is a mechanism that leads to more frequent storm activity just inland from the coast.

Florida is most susceptible to sea-breeze storms because the fronts come from both sides of the peninsula aiding convergence and upward moving air which eventually forms storms.

Can you spot the sea-breeze fronts in the image below?

Yep, they occur on both sides and move towards the center of Florida. It’s those two lines of clouds.  The brighter bulges along the line are storms that have formed along the sea-breeze.  I love weather!!

Keep an eye out this summer.  When it feels nice and sticky out, and the wind begins to pick up from the south…look out.  If the clouds darker, it could turn into an ugly afternoon.  20% chance of rain huh?  Yep. Everyday.

By the way, here is a shot of the rainfall totals over the last seven days. South and southwest Houston received a ton of rain!!  At least the forecast was not totally wrong.  Texas in general received quite a bit of much-needed rain. Thanks Mother Nature!

Have a great weekend everyone!  Thanks for reading!