The technique is a statistical method developed using multiple regression. The following parameters are considered:
There was a marked difference in the maximum gust in relation to upper air data in the case of \(T_x-\theta_w850<9 ^\circ C\) or \(T_x-\theta_w850\geq 9 ^\circ C\). As a result of this multiple regression equations were derived separately.
$$if\quad T_x-\theta_w850<9 ^\circ C:\quad FF_{max}=14.9+0.976*U850+1.27(\theta_w850- \theta_w500)$$
$$if\quad T_x-\theta_w850\geq 9 ^\circ C:\quad FF_{max}=15.9+0.174*U850\sqrt{T_x- \theta_w500} +0.057*U250\sqrt{T_x-\theta _w500}+0.92*(\theta _w850-\theta _w500)$$
where FF_{max} is the maximum gust in knots, T_{x} the maximum daytime temperature (deg C), U850 and U250 the wind at 850 and 250 hPa (kts) respectively and θ_{w}850, θ_{w}500 the wet bulb potential temperature at 850 and 500 hPa (deg C) respectively.
Note that should any of the expressions within the square root operators evaluate to less than zero (highly unlikely in real atmospheric conditions), then the expression will be set to zero internally to avoid arithmetical errors.