My neighbor snitched on me and my shed is too tall given it's location
according to County zoning. My bad.

So, I have to make it shorter by about 18 inches. My plan is to take
off the roof and rebuild a newer less tall roof. Safety wise, I plan to
install some of the new cross supports while I remove the roof to make
sure that the shed maintains its structural integrity during its
retrofit.

My question - would a circular saw be enough to cut through the
shingles and plywood so that I can remove the roof in 2'x6' sections?
Is there a special blade for this? Or, should I invest in a
reciprocating saw?