# sweat_index#

metpy.calc.sweat_index(pressure, temperature, dewpoint, speed, direction, vertical_dim=0)#

Calculate SWEAT Index.

SWEAT Index derived from [Miller1972]:

$SWEAT = 12Td_{850} + 20(TT - 49) + 2f_{850} + f_{500} + 125(S + 0.2)$

where:

• $$Td_{850}$$ is the dewpoint at 850 hPa; the first term is set to zero if $$Td_{850}$$ is negative.

• $$TT$$ is the total totals index; the second term is set to zero if $$TT$$ is less than 49

• $$f_{850}$$ is the wind speed at 850 hPa

• $$f_{500}$$ is the wind speed at 500 hPa

• $$S$$ is the shear term: $$sin{(dd_{850} - dd_{500})}$$, where $$dd_{850}$$ and $$dd_{500}$$ are the wind directions at 850 hPa and 500 hPa, respectively. It is set to zero if any of the following conditions are not met:

1. $$dd_{850}$$ is between 130 - 250 degrees

2. $$dd_{500}$$ is between 210 - 310 degrees

3. $$dd_{500} - dd_{850} > 0$$

4. both the wind speeds are greater than or equal to 15 kts

Calculation of the SWEAT Index consists of a low-level moisture, instability, and the vertical wind shear (both speed and direction). This index aim to determine the likeliness of severe weather and tornadoes.

Parameters:
Returns:

pint.Quantity – SWEAT Index