Stability Assessment » SWEAT Index Skew-T Procedure
From the Skew-T, determine the following values:
- Total Totals index (TT)
- Total Totals index (TT)
- Dewpoint (°C) at 850 hPa (Td850)
- Wind speed (kt) at 850 hPa (V850)
- Wind direction (°) at 850 hPa (dd850)
- Wind speed (kt) at 500 hPa (V500)
- Wind direction (°) at 500 hPa (dd500)
The SWEAT index is computed as follows:
SWEAT= 12(850Td) + 20(TT - 49) + 2(V850) + (V500) + 125(sin(dd500 - dd850) + 0.2)
Note the following rules:
- If TT is less than 49, then that term of the equation is set to zero.
- If any term is negative, then that term is set to zero.
- Winds must be veering with height or that term is set to zero.