Air Force Method of Forecasting Maximum Temperature (TMAX)

There are several ways to forecast maximum temperature from a single sounding. The Air Force developed a simple method to make such forecasts, depending on sky conditions. This method works for locations that are fairly near sea level away from water and not expecting an air mass change. We examine this technique below.

If no inversion is present between 4,000 and 6,000 feet above the surface:

  1. From the morning (1200 UTC) sounding, find the temperature at 850 hPa (T850)
  2. Clear/Scattered clouds: Proceed from T850 dry adiabatically to the surface to get TMAX
  3. Broken clouds/overcast: Proceed from T850 moist adiabatically to the surface to get TMAX

If an inversion is present between 4,000 and 6,000 feet above the surface:

  1. Find the temperature (T) at the warmest point (top) of the inversion
  2. From that point, proceed dry adiabatically to the surface
  3. The resulting temperature at the surface is TMAX
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