If the TAF is:
1 line - you can pretty well go
2 lines - Only people with IMC ratings are going anywhere
3 lines - no one's goin' anywhere
You'll be seeing 4 lines soon... they are going to 36 hour tafs at some places later this year - all the 'times' will extend to be 'day/time', and you can be sure they'll cover every possible option with 'prob30 this and that' within the 36 hours. The decode sites will have to change, wonder how fast that will happen?