To reply to the original (regardless of age) thread, you can look up the applicability of TAF's in an IFR route manual, meteorology section.
The given example 'PROB30 TSRA' situation for a destination or alternate is a transient/showery type of deterioration which is not applicable.
Thus Evo's decision to go was sound and legal.
That it may not be applicable does not mean that you shouldn't consider it as a possibility. Just not a major part of the equation.