So I am taking my practical in two weeks, and I have had conflicting answers from my instructors and wanted to see what everyone else thinks on this scenario.
you get a TAF that reads
KTYS 031124Z 0312/0412 23011G18KT P6SM SCT050 BKN100
FM031400 22014G24KT P6SM SCT040 SCT100 BKN250
FM031900 22019G28KT P6SM VCTS SCT050CB BKN200
FM032200 22020G29KT P6SM VCTS BKN050CB
FM040200 25023G33KT 3SM TSRA BR SCT015 OVC035CB
FM 040400 28022G30KT 4SM SHRA BR OVC020
FM 040700 31017G25KT P6SM OVC020
OK, the question is do we LEGALLY need an alternate? Obviously we would probably plan an alternate because this is just a forecast and we don't know where the thunderstorms will be, or if it will be worse than forecast.
But, from 121.619 "however, no alternate airport is required if for at least 1 hour before and 1 hour after the estimated time of arrival at the destination airport the appropriate weather reports or forecasts, or any combination of them, indicate (1) the ceiling will be at least 2,000 feet above the airport elevation; and (2) visibility will be at least 3 miles"
I am new to all of this, and so I wanted to know if there is a straight forward answer to this, or if anyone else has an opinion on this. My conclusion from reading this is, we don't legally need an alternate here. Because we have the visibility requirement and the ceiling requirement the whole time. But we definitely have convective activity in the forecast. I didn't know if we legally needed one if there was a rule that if we had convective activity, icing, or turbulence in the forecast.
If I were actually dispatching the flight (once I learn everything I need to and actually learn how to dispatch a flight), I would add an alternate because anything can happen with thunderstorms. But if I am asked if I legally need one, I don't want to screw up with the examiner by saying yes or no and not really knowing for sure.
Thanks for the help!