Rewrite the following sentence so that related ideas are expressed in similar or parallel structures.Weather forecasters predicted a hurricane, and...

This is a compound sentence, and the first clause is cast
in active voice ('forecasters predicted') while the second clause is in passive voice
('plans were developed by').

This sentence is fine as it
is, but if one wished to make the clauses parallel, one would have to cast both in
active voice:

Weather forecasters
predicted a hurricane, and local authorities
developed emergency
plans.

OR both in passive
voice:

A hurricane was
predicted by weather forecasters, and emergency
plans were developed by local
authorities.

As you should be able to
see, both of these latter sentences are less interestingly composed than the original,
which demonstrates that parallel structure is not always the best
style.