4. Forecast Applications

Convection » Convective Wind Gusts AFWA T2 Method

Compared to the T1 Method, the T2 method more completely accounts for the effects of the convective downdraft temperature. The T2 Method for determining the speed of the maximum convective wind gust is as follows:

  1. Determine T1 and TMAX as outlined on the previous page.
  2. From the wet-bulb zero temperature, go down a moist adiabat to the surface. This temperature is subtracted from the TMAX to get T2.
  3. Determine the mean wind speed in knots in the lowest 5,000 feet (1500 m). Divide the mean wind speed by 3. This is V.
  4. Compute the maximum wind gust from this formula: V2 = V + 13 * sqrt [(T1 + T2) / 2]

As in the T1 method, estimate the direction of the mean wind in the layer between 10,000 and 14,000 ft (3-4.3 km) AGL. This will be the forecast wind direction of the computed gust.