Weather Hazards

Thunderstorms 

Do you need a Thunder Buddy? ... You just might if you plan to fly near Thunderstorms!

    Thunderstorms are, without a doubt, the greatest weather hazard to aviation operations. All thunderstorms produce conditions that are extremely hazardous to aircraft. Although numerous combinations exist, it's nearly impossible to visually determine which hazards you may face when encountering a deadly thunderstorm (FAA, 2016).

    Thunderstorms form when there is sufficient moisture and the air mass currents are unstable. As warm moist air rises into cooler layers of the Troposphere, the moisture condenses into water droplets. The cooled air drops lower in the atmosphere, warms, and then rises again by the warm updrafts. The cycle of rising and falling is called a Convection Cell. In small amounts, this causes clouds to form. In large amounts, thunderstorms may form. Thunderstorms can be formed by a single relatively small convection cell (SINGLE-CELL), multiple convection cells (MULTI-CELL), or one single very large convection cell (SUPERCELL) (Thunderstorms / Center for Science Education, n.d.).

    The most dangerous type of thunderstorm system in aviation is that of the Squall Line, a narrow band of active thunderstorms that may stretch across an entire state making it difficult to navigate around. (FAA, 2016). Penetrating a Squall Line may also be impossible unless there is a sufficient gap. Although, navigating through a gap in a Squall Line should be avoided because even flying near thunderstorms is risky flying behavior. If a destination airport is beyond a squall line, it would be best to immediately look for a suitable divert airport where one could wait until the storm passes, especially for those pilots who are not IFR-rated and flying VFR.

Thunderstorm Hazards

    Although not all thunderstorms will produce every type of hazard, they typically manifest with a combination of the following hazards:

Hail

    Hail is not only hazardous to ground-laden structures and objects. Hail can be extremely hazardous to aircraft because thunderstorms can "throw" hail outwards for many miles. Aircraft windows, radomes, engines, and other structures may be damaged by hail when encountered. And just because there is rain at ground level near a thunderstorm, don't discount the possibility of hail at higher altitudes.

Turbulence

    Thunderstorms have the potential to create hazardous turbulence; the strongest occurring within the updrafts and downdrafts. Shear Turbulence is also a hazard that can occur several thousand feet above and up to 20 miles away laterally from a thunderstorm (FAA, 2016).

Icing

    The updrafts within a thunderstorm carry large amounts of moist air upwards. As the air cools and condensates it can become supercooled. When this supercooled air comes into contact with an aircraft, it can instantly freeze on the surfaces of the aircraft.

Navigating Around Thunderstorms

    It's not impossible to fly during inclement weather. There are, however some challenges involved in doing it safely. Starting with the preflight weather briefing, a pilot should become familiar with the forecasted weather at the origin, along the route, and at the destination. Before every flight, the pilot should obtain a weather briefing from a Flight Service Station (FSS) specialist. Receiving a proper briefing could potentially be the difference between being caught in a storm, or changing the flight route to avoid a potential storm.

    Advanced avionics equipment such as weather radar or an ADS-B IN Flight Information Weather Service-Broadcast (FIS-B) can serve as invaluable tools when navigating troublesome weather, however, the best resource an aviator has is communication with Air Traffic Controllers (ATC). ATC can route air traffic around storms in real time. It's truly amazing how efficiently a controller can direct air traffic around storms as shown in this video of air traffic into Atlanta-Hartsfield.

References:

Federal Aviation Administration. (2016). Pilot’s Handbook of Aeronautical Knowledge: FAA-H-8083-25B (ASA FAA Handbook Series) (2016th ed.). Aviation Supplies & Academics, Inc. https://www.faa.gov/sites/faa.gov/files/regulations_policies/handbooks_manuals/aviation/phak/15_phak_ch13.pdf

Kappell, J. (2014, May 28). Types of Thunderstorms and the Dangers they Pose - WDRB Weather Blog. WDRB. https://fox41blogs.typepad.com/wdrb_weather/2014/05/types-of-thunderstorms-and-the-dangers-they-pose.html

Thunderstorms | Center for Science Education. (n.d.). UCAR. https://scied.ucar.edu/learning-zone/storms/thunderstorms#:%7E:text=Thunderstorms%20form%20when%20warm%2C%20moist,%2C%20warms%2C%20and%20rises%20again.