FLYING Magazine News Pilot Proficiency Weather

How to Decipher Flight-Level Weather

Here are some tips for finding the smoothest air to fly in.

Friday, November 01, 2024 at 09:32 AM ET

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Most pilots have access to a ton of weather guidance, but if you are routinely flying in the flight levels, here’s one more product to add to your list—constant pressure charts. [iStock]

Key Takeaways:

Constant pressure charts are essential for pilots flying at high altitudes, providing a comprehensive upper-air weather picture for both quantitative flight planning (e.g., optimal altitude) and qualitative hazard assessment (e.g., clear air turbulence), which surface charts do not offer.
These charts depict lines of constant *height* for a specific pressure level (e.g., 500 mb), where lower heights (troughs) indicate cold, dense air and deteriorating weather, while higher heights (ridges) signify warm, less dense air and fair conditions.
Pilots can use constant pressure charts to identify specific patterns, such as split-flow or sharp V-shaped meridional flow, which are strong indicators of potential moderate to severe clear air turbulence due to significant speed and directional shear.

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Understanding the big weather picture is key to making good operational decisions. Most pilots have access to a ton of weather guidance, but if you are routinely flying in the flight levels, here’s one more product to add to your list—constant pressure charts.

Constant pressure charts not only help you with the quantitative aspects of your flight, such as finding the best altitude to minimize your headwind component, but they also help you with a few qualitative aspects, such as minimizing your exposure to uncomfortable clear air turbulence if you know what to look for.

Scott Dennstaedt, Ph.D

Scott resides in Charlotte, North Carolina, and flies regularly throughout the Mid-Atlantic and Southeast U.S. He is a CFI and former NWS meteorologist. Scott is the author of "The Skew-T log (p) and Me: A Primer for Pilots" and the founder of EZWxBrief.