Tuesday, July 15, 2008

Tropical Storm Bertha Sets New Record

Longest-lived Atlantic July Tropical Storm

6:45 Update: More historical data included.

The National Hurricane Center announced this afternoon that Tropical Storm Bertha has set the record for the longest time as a named tropical cyclone during July in the Atlantic. At 12½ days, Bertha has exceeded the 12¼ days for storm #2 in 1916.

Claudette in 1979 originated on July 15 and lasted until July 29, but it was a tropical storm for only 2 brief periods during that time. It did make landfall on the southeast Texas coast, where it caused torrential rains, including a U.S. 24-hour record of 42 inches at Alvin, Texas. The flooding made Claudette the 10th costliest tropical storm in U.S. history up to that time, with damages of $400 million.

Bertha 1996 was also a long-lived storm. It became a tropical storm on the morning of July 5 and was a hurricane from the 7th through the 12th, when it made landfall. It quickly became extratropical, but it retained tropical storm force winds for several more days.

The longest-lived pre-July storm appears to be the would-have-been "B" storm of 1934. It originated in the far western Caribbean on June 4, looped around Central America, the Yucatan, and the Gulf of Mexico, and made landfall as a hurricane on the coast of Louisiana. It then went up the Mississippi and Tennessee valleys, turned east to pass almost directly over the Washington, DC area and went back off the New Jersey coast and over Long Island and Cape Cod. Including the extratopical phase, it lasted 17½ days.

Although conditions have been favorable for intensification, Bertha remains a tropical storm with maximum winds of about 70 mph. It continues to move away from Bermuda on a north northeast track at about 9 mph, leaving behind extensive power outages.

As for Cristobal wannabe, the area of thunderstorms 800 miles east of the Lesser Antilles has become less organized during the day, and the likelihood of tropical depression development has decreased.

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