It was early evening but the skies were already getting dark as as a line of thunderstorms bore down on the city.
I was in the hotel elevator, on my way to go fly. A woman in the elevator noticed my airline uniform and asked where I was headed.
"Newark and then back here in the morning". It was a choice trip and I haven't seen it since.
"In this weather?" she exclaimed?
I just shrugged and said "I don't get to pick and choose".
There lies the problem. In the military, most of what we did was training, and you can always train another day. In this business, the freight's got to move. It's what I'm getting paid for. Or as the joke goes:
"Did you check the weather?"
"Why? We're going anyway."
I hate thunderstorms. Well, I should say that I fear thunderstorms. I fear them almost to the point of phobia. The worst part is I have to deal with them almost on a daily basis. They're either where I'm at, where I'm going or somewhere in between.
It doesn't help that I do most of my flying in the Midwest and Southeast, both of which are frequented by thunderstorms. Spring and summer are the worst but I've seen them come rolling through Tennessee in January. I've even seen thunder-snow in Ohio!
Oh, before we get started, if you have some horrible story about flying through a thunderstorm I DON'T WANT TO HEAR IT! Lalalalalala I can't hear you! Lalalalalala I'm not listening!
Like I said, I don't like 'em. Still, they're a fact of life, so let's take a look at how we deal with them in aviation.
First off, what exactly is a thunderstorm? Sure, we've all seen them but how do they get there? To build a thunderstorm we normally need three things: moisture, an unstable air mass and heat. On any given summer day in the Southeast or Midwest you can watch this take place. You'll see the big puffy clouds start building up as the warm, moist air rises. These are called "towering cumulus". They're not thunderstorms yet, but once they build above 20,000 feet or so it's best to steer clear of them.
At some point most of the moisture has been dumped on the ground and the cell is considered to be "dissipating". This whole process from start to finish may take as little as an hour.
That's the quick and dirty explanation of what makes a thunderstorm. A meteorologist could explain it much greater detail. But what makes them so dangerous? It's what's going on inside.
Inside a thunderstorm is an extremely unstable air mass. Some of the hazards associated with them are:
Severe turbulence (if you've never experienced it pray you never do)
Extreme precipitation (jet engines don't like to drink tsunamis)
Hail (jets don't like getting whacked with ball-peen hammers either)
Severe updrafts and downdrafts (bad, trust me)
Rapidly shifting winds (bad)
And of course, lightning, which surprisingly isn't the worst thing (scary though)
Every Air Force flight manual carried an ominous warning:
Warning. There is no peacetime mission that warrants penetrating a thunderstorm.Hey, you don't have to tell me twice!
The key to dealing with thunderstorms is simple - avoid them at all costs. But how?
Ground based radar
And of course the good old-fashioned Mark One eyeball.
Before going out to fly we always take a good look at the radar picture. The green blobs are rain showers. No big deal. Might get bumped around a little. The yellow areas are heavy rain. I'll avoid those unless there's no other way. The red areas are thunderstorm cells and I will give those a wide berth. Preferably several miles.
Finally let's look at the lightning detection. Large pulses of electrical energy are easy enough to detect. This shows us a time lapse of all the lightning strikes over the last hour or so. They go from most recent (white) to oldest (dark red).
Fortunately my dispatcher does have this information readily available and can send us a message via ACARS that we need to re-route.
Air Traffic Control also can see precipitation on their radars (somewhat) and can give us a heads up. That's not their primary job, however, and if they're busy they may not have time. If they do, they'll use the terms "Moderate", "Heavy" or "Extreme". Generally I don't like to hear the word "Extreme" with anything aviation related.
Our primary tools for weather avoidance are our plane's weather radar the tried and true "look out the window".
In the daytime we look for "towering cumulus" buildups. They're usually easy enough to spot. At night we look for lightning flashes. There is a rule of thumb that yellow flashes are further than 80 miles and white flashes are closer than 80 miles. My very unscientific observation seems to support this.
What the radar is actually picking up is the precipitation inside the thunderstorm. The newer radars can also see the movement of the precipitation and predict turbulence (but only if its associated with precip). The newer radars have color displays similar to the ground-based imagery. Green = not so bad, Yellow = bad, Red = really bad, Magenta = turbulence.
There's a bit of an art to getting the most out of the weather radar and I don't claim to be an expert. Setting the tilt angle of the beam is very important. Point it too low and you end up "painting" the ground. Point it too high and it may not pick up that storm that's right under your nose.
This picture shows a storm cell on airborne radar. We can change the scale of the display. In this case each ring is 20 miles so the storm is 60 miles away. The green line represents the aircraft's flight path. It should pass roughly 10 miles to the left of the cell.
What if you're trying to depart an airport with thunderstorms? It's normally best to wait it out. Thunderstorms are relatively short lived. If you wait an hour, or sometimes even a few minutes, they'll probably move.
Departing Denver one afternoon I see one lonely thunderstorm. It's not even very wide, just a few miles across, but I can see it's very dark and spitting out lightning. No big deal except we're heading right for it.
Me: "Hey boss, I think we might want to go around this thing."
Capt: "Denver, Boxhauler 605 request deviation left of course."
Friendly helpful Denver controller: "I'm dealing with a lot of airplanes here!"
Capt: "I'M NOT FLYING THROUGH THAT CELL!!!!"
Denver: "Roger. Boxhauler 605 clear to deviate."
What about thunderstorms at your destination? You pretty much have to wait it out in a holding pattern. At some point the storms will either clear out or you'll go to your alternate airport when you don't have fuel to wait any longer. We always put extra gas on if storms are forecast at our destination.
This picture shows a line of strong storms just north of Kansas City (KMCI). Kansas City seems to be a magnet for thunderstorms. Flights are getting into the airport from the south, but if the storms move closer they may shut the airport down for a time.
I'd just as soon not find out first hand. It's very undignified when I start shrieking like a little girl.
I'm told that due to global warming I can expect larger and more frequent storms. So I've got that to look forward to.
Stay safe out there.