Twenty-five hundred feet mean sea level (msl), 1,500 feet above ground level (agl), smooth air, 130 indicated at 65 percent power, and my GPS is showing 146 knots over the ground because of a tailwind. I’m heading north into Missouri from a visit with my dad in Fort Smith, Arkansas. I left in clear skies and cool morning air on the day after a summer scorcher. The humidity was 98 percent and last night’s thunderstorms were still lurking to the north. For the past 30 minutes I had been watching the Nexrad as a blotch of bright red crossed the magenta line between me and home. “No problem,” I said to myself, “these things run out of steam and fall apart this time of day.” It isn't always good to be right.
Just 24 hours earlier, I was following the same magenta line heading south. That previous day I climbed to 8,500 feet msl to catch the northerly winds up high and get out of the hot, humid air below. The air at 8,500 was cool, cloudless, and smooth, but it was rough with thermals below. I thought, This is going to kick something up later.
Sure enough, by evening some nasty storms had built up to the northwest and were headed southeast overnight. I kept a wary eye on them, but by the time I was ready to leave on Sunday morning, red was mostly giving way to orange, which was in turn changing to yellow. I decided to launch at 8 a.m., as it looked like the path would clear ahead of me.
An hour into the flight, the air was smooth and the last red blotch on the radar lay 20 miles east of my course from where it had crossed 10 miles ahead. Visibilities were greater than 10 miles, the air was smooth, and ceilings were so far above me that I didn’t even bother to check what they were. No clouds at my altitude, except—what is that odd cloud up ahead?
Wow, that’s an odd cloud. It’s all by itself, halfway between the surface and the overcast above, stretched across my path several miles each direction. I wonder what kind of weather anomaly would cause that?
I was about to find out. I was admiring what looked like a gray garden hose until I got close enough to see that this thing was rolling backward as it moved forward. I was set to cross under this skinny little cloud (it was only about 600 to 800 feet in diameter and four to five miles long) with adequate VFR clearance. I could see that there were no other clouds behind it. Clear air. No big deal, right? Until I noticed the backward roll of the cloud.
At the same moment that I realized what this thing was, the gust front hit me. The wind sheared from a 15-mph tailwind to a 25-mph headwind. Airspeed immediately spiked into the yellow arc and my little Musketeer was in an uncommanded 2,000-fpm climb while still in a level attitude. I shoved the nose down, and the tach went from 2450 to 2700. The words of my CFII came to me from when we were flying cross-country in instrument meteorological conditions. “Don’t fight the updraft with pitch, reduce power and watch your attitude.” I reduced power to keep from overspeeding the engine and I was still climbing at 1,000 fpm.
I fixed my eyes on the artificial horizon in preparation for zero visibility, sure that this thing was going to eat me for lunch, when—as I passed under the cloud—the climb stopped. I skimmed the bottom of the cloud, keeping the airplane level by releasing forward pressure. Then the thought hit me: Oh, no, this thing must have a back side.
Oh, yes—yes, it did. Just as I shoved the throttle forward, the other side of this thing found me. Full throttle, nose in climb attitude, and headed for the ground at 1,500 fpm. The sensation was just like doing an autorotation in a rotary-wing, but this was my first autorotation-style descent in a fixed-wing. The downdraft relented at roughly 500 feet agl, and I was able to resume normal flight, but the outflow from the storm had reduced my groundspeed from 146 knots to 109.
This cold, dissipating storm outflow had a rolling wave at its leading edge as it cut under the warm air blowing at it from the south. It’s similar to the dust cloud you see rolling across the ground when they implode a building with explosives. The cell that caused it had already moved many miles off to the east, but it left this nasty little offspring in its wake. If not for my XM satellite weather, I wouldn’t even know what had caused it.
In the future, I’ll stay well clear of odd clouds near dissipating thunderstorms. They bite.
