With the clock running down — literally, a digital countdown clock on The Weather Channel — an otherwise unremarkable and unthreatening tropical storm named Humberto fell just short of making history early Wednesday.
The National Hurricane Center announced at 5 a.m. that Humberto had reached hurricane strength, leaving it No. 2 on the list of the latest-forming first hurricane in nearly a half century.
Gustav, which was declared a hurricane at 8 a.m., Sept. 11, 2002, retained the record by three hours — at least pending further review. The center always conducts a post-storm analysis that potentially could change estimated wind speeds along its track.
With hurricane season passing its historical peak on Tuesday, there were some signs of increasing activity after a pleasantly quiet first three months.
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By evening, Humberto’s winds had increased to 85 mph but it remained thousands of miles from the United States and no threat to land. Forecasters expected it to linger for a few days before weakening in the cold waters of the Atlantic Ocean. A regenerated Tropical Storm Gabrielle continued to weaken as it moved north after sweeping across Bermuda with 60 mph winds overnight.
Forecasters also were monitoring a low pressure system in the northwestern Caribbean Sea near the Yucatan Peninsula, giving it a strong chance of becoming at least a tropical depression over the next five days, as it drifts westward toward Mexico. They also were watching another broad less organized mass of storms drifting toward the Leeward Islands but giving that only a 10 percent chance of becoming a tropical depression or storm.
Robert Molleda, warning coordination meteorologist for the National Weather Service in Miami-Dade, cautioned that while Sept. 10 represents the statistical peak for the number of Atlantic storms, risks remain high for South Florida for at least the next two months.
In records going back to 1865, 46 hurricanes have struck mainland South Florida — with 28 of them coming after Sept. 10. That’s 61 percent, Molleda said. Nineteen have struck South Florida in October alone, when storm formation shifts from the African coast to the Caribbean and the Gulf of Mexico and steering currents tend to make South Florida more vulnerable.
“Sometimes people interpret the peak that it looks like we’re halfway done,” he said. “We still have really what is historically the busiest time of the year ahead.”
Scientists say the most obvious factors tamping down storms so far this year appear to be dry air, a combination of dust clouds swirling from Africa’s Sahara Desert and dry, sinking air over the open Atlantic but other atmospheric factors also may play a role.
In the average year, the first hurricane typically arrives by Aug. 10.
Hurricane center spokesman Dennis Feltgen said first hurricanes in September are unusual but not unprecedented. Records dating to 1851 show 15 years when the first hurricane formed after Sept. 5. But Gustav was the latest since 1967 and the dawn of satellite tracking. The all-time latest came on Oct. 8, 1905.