From a Lakewood news site- Bracha for Hurricane sandy.
The Mechaber (227,1) paskens one makes the bracha of “oseh maaseh breishis” on very strong winds. Suffice it to say hurricane strength winds fall into the Mechaber’s category of strong winds. The question is how strong should the winds be to make the bracha at the ideal time.
Lakewood poskim have told us the tzibur should wait until there is sustained winds of over 60 mph. Since the storm is expected to intensify over the course of the day, one should wait until the evening hours when the wind will be howling at nearly 80 mph.
Tomorrow morning one doesn’t make a new bracha as it is the same storm as today