Out Of The Pattern

Ten a.m., July 4. Yesterday's heavy afternoon squalls cooled the earth enough to produce a thick morning mist that's lifting now as an onshore breeze begins to blow. I'd welcome the break from our relentless tropical sun if it weren't for the stifling humidity; it feels as if we are living and breathing underwater at this time of year. The dampness clings to everything-but that's typical for summertime in South Florida. Wet mornings, sizzling noons, and soggy by 3 p.m. It is a tough time of year to fly airplanes.

The lifting mist congeals into pillows-a scattered-to-broken deck that pins VFR-only pilots below 1,000 feet agl in the mornings. Later, the sky-a perfect delft-blue color-peeks through the ceiling of clouds, beckoning. Any local pilot will tell that VFR-only flier to sit still for just a half hour more. The pillows of water vapor quickly billow upward and outward. I've had so much practice watching this phenomenon that I can calculate what time of day those adolescent storms will mature by looking at them and then at my watch. I judge their varying heights, girths, and the heavy bulging grayness of their undersides. I'm estimating a 2 p.m. eruption, looking up and wondering what I've got to do around that time. Ah, yes, today I have a student who wants to squeeze in one flight before the day gets wet. I said we could try. After all, the weather isn't always on time.

Just by looking at those clouds, I can determine which ones I'm willing to fly under and which are about to blow; which are likely to hammer me with turbulence and which are benign-for the moment. They will almost all become thunderstorms on this hot July day.

The peninsula of Florida has its own distinct summertime weather pattern caused by the diametrically opposed heating and cooling of the earth and water. In the mornings, when the water is still relatively warm, the earth is cool after releasing its heat into the night air. Any thunderstorms will be offshore. As the sun warms the ground, however, the thermals carry moisture from it, and before the sun reaches its zenith, there are plenty of fair weather cumulus clouds over the land.

The rising air creates a pressure drop that draws up a nice onshore flow of moist air-remember those morning showers over the water-which feeds the clouds above it. It doesn't take long before those puffies are behemoths ready to kick up a major afternoon fuss of thunder, lightning, and heavy rain.

Despite my airplane being equipped with radar and Stormscope and Strike Finder, I find that in the summertime I fly almost exclusively VFR. When I do use my IFR ticket, it is generally to pop up out of persistent ground fog. I don't fly in summertime rain around here if I can help it because the rain is associated with thunderstorms.

Two thousand feet is a good altitude to fly VFR in the afternoons in South Florida. From that height I can easily see the bases of the clouds, which are usually between 3,000 feet and 5,000 feet, and I can choose which ones I'll fly under. If I find myself surrounded by rapidly maturing cumulus I start to take inventory-not of my emergency rations but of the clouds. I know that I don't want any part of a massive cumulus with heavy, gray, churning bumps on its bottom (they scream turbulence). I'll also avoid those spewing virga or trailing chunks and wisps of scuddy cloudlets beneath. Those clouds all signal the makings of a major afternoon thunderstorm. I also watch the southwest corners of any particularly mean-looking clouds because that's where tornadoes may begin their spin.

I circumnavigate any active storms by 20 miles or more, depending on the storm's severity. When flying my circle, I make sure that I'm not caught under a storm's far-reaching anvil top. Many a pilot has been pummeled with unexpected hail spit out of the top of a storm and hurled 20 miles or more in the direction of the prevailing winds. I stay upwind of anvil tops when I can.

I have heard many stories about the best altitudes to penetrate a thunderstorm and how to handle an airplane in hard IFR, heavy turbulence, lightning, and rain. Frankly, I subscribe to a simpler plan-don't. In summer, most of my flying is planned for the morning hours. I try to avoid the afternoon and all of the peculiar challenges it lobs my way.

Today, though, I'd been hoping the morning mist would slow the progress long enough for my student and me to get in a few afternoon takeoffs and landings. Some days it does. I head out to the hangar to pick up my flight case. There is a distant rumble and a fat, wet droplet plops down, making a flowery decoration on my cotton blouse. I check my watch: 1:45 p.m. I look up. There's a big cumulus cloud right over the airport. I turn back to the house and settle into the rocker on the front porch to watch the afternoon fireworks proceed. Staying on the ground at times like these is my own good advice. I take it.