A Customer recently said to me: "I checked the weather for my flight and there are thunderstorms in the forecast. I am worried about what may happen as we fly along."
(Here goes Ray on another wacky analogy so hold on....)
Think of a thunderstorm as a giant tree --that moves!
If you get in your car to drive to the mall, all the real trees are along the roadside, and are unlikely to jump in your way. If we imagine thunderstorms as trees that move about, you can see that we would rather go around a tree as it moves into the road ahead rather than hit it.
Same with planes and thunderstorms. Other than a little chop, the only problem a thunderstorm presents to a plane is when it moves near the airport that the plane is either departing from or flying to. Pilots will avoid hazards by using different runways, holding short of the airport waiting for the thunderstorm to move on, or Pilots may choose to fly to an alternate airport to wait out the storm. In every case, the Pilots and airline Dispatchers make informed decisions on what obstacles are in their way and make plans to deal with these issues in a safe manner. If none of these options look feasible, the flight may delay takeoff until the destination airport will be in the clear.
Remember the satellite images of weather on the ground? That shows Crews and Dispatch personnel where the weather threats are. They deal with these weather phenomena all summer long. Relax, as they will do what they usually do, and take the most prudent and safest approach, which usually means avoiding them.