@Setanta,
Setanta wrote:
I have read, although i cannot vouch for the accuracy, that Florida gets more thunderstorms and more lightning strikes than any other comparably-sized area on the planet. I'll go see what i can find . . .
This is from PBS:
Quote:Lightning Alley
An area in central Florida, midway between the Gulf of Mexico and the Atlantic Ocean, which sees the formation of countless thunderstorms during the summer months, and is prime lightning territory. It receives more than 12 lightning strikes per square kilometer, per year, the highest level of lightning activity in the United States.
A Natinoal Weather Service page said that the high occurance of lightning and thumderstorms in central Florida results from its position mid-way between the Gulf and the Atlantic, and from the Gulf Stream swinging inshore there.
I don't know the stats either, but I suspect you are right. I believe the geographical feature that makes the frequency of thunder boomers so high in Florida is that wind flows, from virtually any direction, bring moisture-laden air over the Florida forests and grasslands - the perfect conditions for solar heating-induced convective build up of these storms.
The rising water vapor cools 2-3 deg F per 1000 ft of convective rise due to decreasing air pressure, quickly reaching saturation (100% relative humidity). Condensation follows, and, because condensing water releases 1000 times the thermal energy required to raise its temperature 1 deg F, it quickly accelerates the expansion and velocity of the rising congestion current - a self-reinforcing feedback loop that ends only when the vaporized moisture is exhausted (often as high as 25,000 ft.
From a flying perspective isolated thunderstorms are generally avoidable (unless one is stupid). The scariest ones occur in fast-moving warm fronts, often over the great plains, These are imbedded in larger weather systems and hard to pick out from surrounding clouds. Most commercial flights are now well above the cloud tops, but perhaps some geezers here can recall long flights in propeller driven aircraft through storm systems : one could never tell when/if he would venture into a boomer hidden by surrounding clouds.
In any event the energy in these systems is truly formidable, and they develop quickly.
I have my own theory about the loss of the Air France aircraft over the South Atlantic enroute from Brasil to Europe. High altitude T storms are rare over the ocean , except in equatorial areas dominated by the trade winds. There they can grow very high. I believe they flew into one (perhaps inadvertently) with the autopilot engaged - a big error. The triply redundant Pitot tubes measuring airspeed all froze up, removing a critical input to the flight control computers (and possibly leaving the pitch controls with too much gain) and, probably in a strong downdraft, the autopilot stalled the aircraft in a fruitless effort to maintain altitude.
