(CNN)All eyes are on Hurricane Florence and its path toward the Carolinas, but other hurricanes are brewing as well. And the timing couldn’t be more apt: Monday was the peak of the Atlantic hurricane season, when storm activity has historically been at its highest.
This storm is lined up behind Florence in the Atlantic.
“Isaac is a small hurricane,” the National Hurricane Center
reported Monday at 5 p.m. ET. “Weakening is forecast to begin by the middle of the week as Isaac approaches the Lesser Antilles.”
Winds of tropical storm force could reach Puerto Rico on Thursday evening. Tropical storms generate winds between 39 and 73 mph, just below hurricane force.
No coastal watches or warnings were in effect as of Monday afternoon.
Still closer to Africa than North America, Helen is predicted to head north in the Atlantic and not make landfall, the center says.
Sustained winds were at 105 mph. “Some strengthening is possible during the next 12 to 24 hours, but gradual weakening should begin thereafter,” the hurricane center said.
Tropical Storm Olivia
Over in the Pacific, this storm is still moving toward Hawaii, where tropical storm warnings and watches have been issued, the hurricane center said.
A tropical storm warning means that tropical storm conditions are expected somewhere in the warning area within 36 hours, and a watch within 48 hours.
Maximum sustained winds were about 70 mph Monday afternoon and the storm was downgraded from a Category 1 hurricane, the hurricane center said.
“Please keep in mind that the difference between a Cat 1 and a TS is only 5mph!” the National Weather Service office in Honolulu said. “The threat of damaging winds, flooding rain, high surf, and storm surge still remains. No change to watches/warnings. Don’t let your guards down!”
Gradual weakening is expected as Olivia continues to approach the main Hawaiian islands.
Large swells could be generated and cause damage in some parts of the state, which survived brushes with hurricanes Hector and Lane in recent weeks. Olivia is expected to produce total rainfall accumulations of 10 to 15 inches.
Gov. David Ige signed an emergency proclamation that will provide relief for disaster damages, losses and suffering and “to protect the health, safety and welfare of the people” as Olivia approaches.