The following refers to the Windshear/Turbulence bit:-
...these figures are approximate/(more accurately..'emperical')
CAT may be expected in regions where :
(a) Vertical wind shear is greater than 4 knots per 300 m.
(b) Horizontal temperature shear is of the order of 5 deg Centigrade per 150 km.
(c) Horizontal windshear is greater than 25 knots per 150 km (moderate) and 50 kt per 150 km (severe).
JG