David,
The FAA has a facility in Warrenton Virginia called the Air Traffic Control System Command Center (ATCSCC). There are air traffic controlers, meteorologists, and airline representatives there (among others). These men and women work 24 hours a day, evaluating traffic levels, airport and route capacity, and weather events. When storms disrupt the airline preferred flight paths, the ATCSCC coordinates and assigns alternate routes. This is discussed on a telecon every 2 hours with all the pertinent people. The users (airlines) can than plan for these new routes and adjust theirs plans (such as fuel on board, extra enroute time, etc) So, have no fear, plans a, b, c, etc are already being considered and ready to be implemented. One thing to be aware of is that some reroutes add significant additional mileage to some trips. This extra time can disrupt schedules or in some cases even make it unfeasable for an operator to fly a particular flight. So stay in touch with your airline for schedule changes, be flexible and understanding of busy employees, but be confident that your route will be safe.