Yellow Evan wrote::uarrow: The fact that the 30s through the 60s were more active than the 70s and 80s? And thus the correlation with seasonal activity with AMO? Plus we have recon going back to 1943 and also the ATL hurricane re-analysis.
Statistics, for example, requires a sample size significantly larger than the standard deviation to be meaningful. Basically we are attempting to draw conclusions about 30-40 year periods of time using only 80 years of historical record. This, to me, is questionable. Sure, you might seem to discover a pattern but it could be noise. There's no way to be sure. The solar cycle, on the other hand, is very cyclical. It clearly runs on an 11 year cycle. There have been enough cycles observed to be sure that it's an 11 year cycle. But you cannot be sure that a 30 year cycle is really a cycle if you're only looking at 60, 70, or even 90 years of record. It might not be a true cycle at all. Or it might be a cycle that is caused by another weather or geological phenomenon. Someone that observes my daily driving habits for only three days might draw a mistaken conclusion of how often I go to the grocery store.