As chairman and chief executive officer of JPMorgan Chase & Co., Jamie Dimon is perhaps the most powerful person in the banking industry anywhere in the world. So when he says — like he did on June 1 — that investors should brace for an economic “hurricane,” it’s worth taking the warning both literally and seriously. Such advice, however, doesn’t seem to extend to the bank’s top-ranked analysts, whose jobs are to advise companies and investors on where the economy and financial markets are headed.