February 16, 2007
Florida’s Central Gulf Coast: Lightning Capital of North America
By Darack, Ed
Barely above sea level, dotted with lakes and swamps, and surrounded by semi-tropical waters, the Florida Peninsula is so dominated by moisture that this land is probably best described not as terrestrial at all, but as terraqueous.Enveloped by warmth and humidity for much of the year, the peninsula's skies deliver wave after wave of rain, most famously from lumbering hurricanes, but far more frequently from swift, ephemeral thunderstorms. Sometimes solo, sometimes marching in groups across the landscape like armies, the towering storms form more often in the skies above the Florida Peninsula than in any other location on the continent. The highest concentration of thunderstorms occurs over the state's central Gulf Coast, the lightning capital of North America.
A map view of the Florida Peninsula grants quick insight into why so many thunderstorms sweep across Florida each year: the warm Gulf of Mexico lies to the peninsula's west, the Caribbean Sea to its south, and the Atlantic Ocean to its east. A more detailed analysis of the peninsula's climate reveals the influence of the tepid Gulf Stream current, which originates in the Gulf of Mexico, runs southward along the peninsula's west coast, and then wraps around the Florida Keys before shooting north along the state's east coast.
The peninsula is practically immersed in warm, moist air- thunderstorm fuel. Furthermore, while rolling hills define a few parts of the Florida Peninsula, this region is largely devoid of topographic relief. The highest point in the peninsula is the 312- foot Sugarloaf Mountain, northeast of Tampa Bay (Britton Hill in Florida's Panhandle is slightly higher at 345 feet above mean sea level, making it the highest point in the state). This flatness allows thunderstorm cells to go freely wherever winds drive them. Wind is the essential factor in why the central Gulf Coast is the thunderstorm-and lightning-capital of North America.
During the height of thunderstorm season, sea breezes drive moisture-laden air from both coasts inland, and seasonal pressure ridges corral these moving air masses into a corridor that runs through the middle of the peninsula. But the Atlantic sea breeze is typically more powerful than that of the Gulf, so the air masses don't meet in the middle of the state. Instead, they collide in the central Gulf Coast region. The amount of incoming solar radiation, called insolation, reaches its zenith in June and July, convectively lifting these air masses during sweltering summer afternoons and evaporating water from the moist landscape below.
As early evening arrives, lightning can be seen flashing as rapidly as 30 times per second in any of these storms. These dramatic cumulonimbus, called by some the "mountains of Florida," eventually succumb to a nighttime death. Just a few hours later, however, the lightning life cycle of the central Gulf Coast will begin anew at dawn.
Lightning strikes the turquoise waters, white sand beaches, and lake-studded flatlands of Florida's central west coast more frequently than in any other region in North America. The city of Tampa, which derives its name from a local Native American word likely describing furious lightning strikes, lies in the heart of this thunderstorm corridor.
Two primary seasons (the cool and the warm) interposed by two transitional seasons (spring and fall) define the Florida Peninsula's annual climate. While thunderstorms can and do strike the state during the cool months of November through February, the skies of Florida-specifically those of the central Gulf Coast region- are most prolific in generating lightning-wielding cumulonimbus cells during the warm season. Once the relatively tranquil winter months have passed, the skies above the state's central Gulf Coast become convectively restive from March through May. In the warm season of June through September, thunderheads roar across the region almost daily.The majority of the average 100+thunderstorm days per year in the Tampa Bay region fall in June and July. And with this North American record number of days with thunderstorm activity comes an average lightning-strike density of 14.5 strikes per square kilometer annually, the highest on the entire continent.
Long before Europeans arrived and decimated the local native population, the Colusa Indians thrived in what would later become known as central Florida. One of the major hubs for the Colusa was a town they called "Tanpa.""Tanpa" ultimately became "Tampa," as the latter is easier for those of European descent to pronounce. However, historians continue to debate the actual meaning of "Tanpa." Some claim the word translates to "place to gather sticks," referring to driftwood found in the area and used for firewood. Other historians contend that "Tanpa" translates to "sticks of fire," indicating "sticks" of lightning.
The two translations aren't necessarily contradictory. Their connection becomes apparent during Florida's rare droughts: lightning storms during the drier, cool season have spawned wildfires that have incinerated tens of thousands of the peninsula's acres.
While Florida's central Gulf Coast can claim more thunderstorms and lightning strikes per year than any other place in North America, it pales in comparison to the global king of cumulonimbus activity; the mountains of Rwanda in Equatorial Africa boast over 200 thunderstorm days annually (Rwanda lies on the equator, so it has two warm, rainy seasons).
ED DARACK is a freelance writer/photographer; visit his website at www.darack.com.