4. Forecast Applications

Turbulence » Thermal Turbulence Skew-T Procedure

In the absence of significant air mass changes during the warm season, a single-sounding method may be employed to infer turbulence in convective clouds. The so-called "Eastern Airlines Method" is an empirical method developed by comparing pilot reports of turbulence with analyzed soundings.

Procedure:

  1. Find the convective condensation level (CCL)convective condensation level (CCL)
  2. Proceed upward from the CCL along a moist adiabat to 400 hPa and determine the parcel temperature (T')
  3. Subtract the observed 400 hPa temperature (T400) from T' and call the result Delta-T.
    Delta-T = T' - T400.
  4. Determine turbulence intensity from the table below:
Delta-T (°C) Turbulence Intensity
0 - 3 Light
4 - 6 Moderate
7 - 9 Severe
>9 Extreme