Thursday, May 10, 2007

Andrea Arrives Early

The Atlantic hurricane season is supposed to start in June but no one told Andrea. Wednesday, Andrea, a small, weak subtropical storm east of Jacksonville, became the first named storm of the 2007 hurricane season.

And while tropical storms and hurricanes are rare outside of the official June 1 through November 30 hurricane season, a few storms have developed in other months.

The most recent example was Tropical Depression Olga, a system that threatened the Bahamas on December 4, 2000. The storm dissipated before reaching the islands.

In February 1952, a tropical storm made landfall across southern Florida. Nicknamed the Groundhog Day storm because it formed on February first, it moved over Key West, Miami and Boca Raton.

The storm produced wind gusts of 68 mph and rainfall amounts of 2 to 4 inches across South Florida. The unseasonable combination of wind and rain damaged vegetable crops in the farming areas of Miami-Dade County.

Another out of season storm hit Florida in December of 1925. On November 29, a tropical storm formed in the western Caribbean Sea. In less than 24 hours, it had intensified into a hurricane, moved into the Gulf of Mexico and made landfall near Tampa Bay. Yet, this persistent storm wasn’t done yet.

It crossed Florida, weakened to a tropical storm while spreading heavy rain and gusty winds across the central part of the state. On December 1, the storm became a hurricane again off the coastline of St. Augustine, eventually making landfall for a second time along the Outer Banks of North Carolina.

The storm produced widespread damage across Florida and North Carolina and is responsible for more than 50 deaths, mostly on ships at sea.

Most out of season storms have formed in May. Records from the National Hurricane Center dating back to 1886 indicate that 18 tropical storms and hurricanes have formed in May. Three of those storms ended up in Florida.

On May 31, 1934 a weak tropical storm swept along the east coast of Florida. Subtropical storm Alpha crossed northern Florida and southern Georgia on May 23, 1972. The storm reached tropical storm strength over the Atlantic Ocean a few days later. And in May of 1975, another weak tropical storm swept across northern Florida.

Out of season hurricanes are relatively rare but do occur from time to time. One of the most unusual was Hurricane Able, a storm that made a complete loop north of the Bahamas in May of 1951. Able was a strong hurricane reaching category three intensity off the coast of Cape Hatteras, North Carolina.

Still, around 97 percent of all tropical systems are well behaved, forming during the official June 1 through November 30 hurricane season.

By the way, officials at the National Hurricane Center say there is no correlation between an early start to the season and active or inactive season. An out of season tropical storm like Andrea is an oddity and has no impact on the number of storms that will form this year.

Posted at 11:58 AM

Friday, May 04, 2007

Predicting The 2007 Storm Season

I don’t know about you, but I really liked last year’s hurricane season. Only five hurricanes formed during 2006 and, for the first time since 2001, none of the tropical systems came anywhere near Florida.

In fact, to give you some idea how unusual last year turned out to be, the tiny island of Bermuda was threatened and hit by more tropical storms and hurricanes than any other location in the Atlantic basin (Atlantic Ocean, Caribbean Sea and Gulf of Mexico)

Of course, while 2006 was a great year to live in Florida, 2005 and 2004 were no fun at all. In 2005, the Sunshine State was hit by four hurricanes in six weeks (Charley, Frances, Ivan and Jeanne), while in 2005 there was so many tropical systems forecasters actually ran out of names. A record 15 hurricanes formed that year including Katrina, the costliest hurricane in history and Wilma, a nasty late October storm that slapped South Florida silly.

Speaking of records, from 1995 to 2006, the National Hurricane Center recorded 98 hurricanes in the Atlantic Basin, the most tropical systems ever recorded in 12-year period. Scientists who study hurricanes say this dramatic increase in tropical cyclone activity is a natural cycle that is likely to continue for another 5 to 10 years.

During that same time, the Earth’s temperature was steadily rising, the result of an increase in greenhouse gases. Global warming is real and, another group of scientists argue, must be helping to increase the number of tropical storms and hurricanes in the Atlantic basin.

The issue has become one of the hottest debates in science and is the subject of a new study by Dr. Chris Landsea of the National Hurricane Center. Landsea is part of the group that believes the recent increase in hurricane activity is a natural cycle and he thinks he has the evidence to prove it. Actually, it is a lack of evidence that may prove Landsea is correct.

Landsea says scientists who believe global warming is responsible for increased hurricane activity may have underestimated the number of storms in the Atlantic basin before weather satellites. An average of three storms each year were not counted during the late 1800’s and the first half of the 20th century because they didn’t hit land or came near a ship at sea, reports Landsea in his study published in the American Geophysical Union.

“When you add those storms back into the record, we don’t see any new trend,” Landsea told the Miami Herald. “There’s no link to global warming that you can see at all.”

To support his theory, Landsea’s report displays tracking charts of the two most active hurricane seasons on record: the 2005 and 1935 hurricane seasons. In the 1933 chart, all the storms appear close to land with none in the central or eastern Atlantic. The 2005 hurricane chart, on the other hand, is full of tropical storms and hurricane covering all of the Atlantic Ocean.

You can read the full report by clicking here.

Landsea points out that before weather satellites began scanning the oceans for tropical trouble makers, the only way scientists knew if a storm had formed was from a ship report or if a hurricane struck land.

“It seems obvious that there's a big gap in how we monitored things in the pre-satellite era,” Landsea said. “Sometimes, you just have to state the obvious.”

While Landea’s study is full of compelling evidence it is unlikely to easily sway the opinions of the global warming proponents. Meanwhile, residents of Florida and other hurricane prone areas of the world, wait and wonder what the 2007 hurricane season will bring.

Posted at 8:20 AM