Weather is a powerful force in the success of each jump.
"It takes patience to get just the right weather conditions." Don Day, Team Meteorologist
One of the primary factors affecting the success of the Red Bull Stratos mission is the weather. It's also one of the most unpredictable.
The wind must be calm. Susceptibility to wind variation increases with balloon size and the Red Bull Stratos balloon is massive. Further, the balloon is only .0008 inches thick (10 times thinner than a sandwich bag). Even before takeoff, the 55-story-high envelope could tear if caught by a wind gust or overturn the mega-ton crane that positions the capsule for launch. Take-off will not be authorized if winds exceed 2 miles per hour from ground level through to several hundred feet in altitude. The team will assess winds throughout the mission - especially at the border of the stratosphere, where turbulence is common. Also, because the balloon will be steered using wind currents, determining wind patterns aloft will enable the team to predict the landing zone even before launch.
Precipitation - whether in the form of snow, ice, rain or heavy fog - could impair visibility for the team and the performance of the balloon. Precipitation of any kind, or even excess humidity, will prevent a launch. Excessive frost or ice build-up on the balloon could impede takeoff or ascent by adding potentially hundreds of pounds to the weight of the payload.
To comply with U.S. Federal Aviation Administration regulations, the Red Bull Stratos balloon will not fly if skies are more than 5/10 (half) overcast or if the horizontal visibility at any point is less than 3 miles. Clear skies will enable better tracking of the capsule's ascent and Felix Baumgartner's descent, and will provide Felix with the best possible conditions for orienting himself in the sky.
Another kind of phenomenon that will be tracked is solar flares, bursts of explosive activity on the sun. Such activity can create "solar storms" that affect satellite and radio communication. Fortunately forecasters can see solar storms coming because it takes many hours - usually days - for the effects to reach Earth's atmosphere. The mission team will plan the launch to avoid solar flares.
Predicting and Tracking
Because all these factors directly impact the ability to launch, Red Bull Stratos meteorologist Don Day minutely examines both historical and current weather profiles. Using computer weather models to predict conditions up to 130,000 feet, he creates flight and landing trajectory projections and he advises the team about windows for tests and the final launch.
To verify these windows, Don and the team release balloons to assess conditions above Roswell, New Mexico, and also receive data on upper-level conditions from balloons launched twice daily at El Paso, Texas, and Albuquerque, New Mexico. Even so, conditions can change unexpectedly only hours before take-off - or during the mission itself. The Mission Control Team will receive meteorological readings throughout the mission and keep Felix informed to ensure a safe flight.