i guess the "problem" i have is that you may be diverting to a field which has the same (sct CB TSRA) forcast / actuals
therefore diverting from one bit of shi%^& WX to a alternate with the same!!!
not ideal to say the least...
That's why I said to PLAN APPROPRIATELY! If there are no distant alternatives available, and all the close alternates have the same forecast, then consider not taking off! Otherwise, look at the weather in the descent and divert to the distant alternative before you get low (You DID load the needed fuel, didn't you?).