Hurricane season is over--but not typhoon season!

The remarkably unremarkable Atlantic hurricane season of 2006 has now officially passed into the history books with the arrival of November 30. The nine named storms, five hurricanes, two intense hurricanes, 50 days with a named storm, and 20 days with a hurricane were all very close to the averages one expects for an Atlantic hurricane season. The only Atlantic hurricanes to affect land were Hurricane Gordon, which passed through the Azores Islands on September 19 as a Category 1 hurricane with 75 mph winds, and Hurricane Florence, whose eye passed about 50 miles west of Bermuda on September 11 and brought sustained 80 mph winds to the island. Neither hurricane did significant damage. The only significant damage done by a 2006 Atlantic storm was Hurricane Ernesto, which caused about $100 million in damage to North Carolina and Florida August 31-September 1. Ernesto was also responsible for the only fatalities of the season--five people in Haiti, and two victims in Florida. We were very fortunate, indeed, compared to the vicious hurricane seasons the previous two years!



A few interesting highlights from the 2006 Hurricane Season, taken in part from Dr. Bill Gray and Phil Klotzbach's forecast team at Colorado State University:

It was another early-starting season. Alberto formed on June 11. The climatological average date for the first named storm formation in the Atlantic, based on 1944-2005 data, is July 10.

The 9 named storms, 2 intense hurricanes, and 50 named storm days were the lowest observed since the El Nino year of 1997.

This is only the 11th year since 1945 that no hurricanes have made United States landfall.

No Category 4 or 5 hurricanes formed in the Atlantic basin this year. This is the first year with no Category 4-5 hurricanes in the Atlantic since 1997.

No named storms formed in October. This is the first time that no named storms have formed in October since 2002. Prior to 2006, only eleven years since 1950 witnessed no named storm formations in October.

Only two named storm days were observed in October (from Isaac which formed in late September). This is the fewest named storm days in October since 1994, when zero named storm days were observed.

Citizens Property Insurance Corp. increased their average homeowner rate by 56% in Florida this year, with another 27% increase scheduled for January 1. Imagine if another year like 2004 or 2005 had affected Florida what the insurance rates might have done!

27 percent: The Citizens rate increase approved to start Jan. 1.

Typhoon season is definitely not over!
Hurricane season may be over in the Atlantic and Eastern Pacific, but typhoon season continues in the Western Pacific. Tyhoons are common well into December most years, thanks to the large expanse of warm waters and the lower vertical wind shear experienced there compared to the Atlantic.

Typhoon Durian slammed ashore in the northern Philippine Islands this morning as a powerful and very dangerous Category 4 typhoon. Durian (named for a spiky tropical fruit) continues to track westward across the Philippines, pounding the the region with its 145 mph winds and rainfall amounts exceeding 12 inches per day (Figure 2). The winds and pressure at Calapan , the next major city Durian is expected hit, will be worth watching today. Durian remains in an environment of weak vertical wind shear, warm ocean waters, and favorable upper-level outflow, and should be able to maintain its Category 4 strength for another 12 hours, resulting in a very severe pounding for the Philippines. Beyond that time, interaction with land, dry air over the South China Sea, and increasing vertical wind shear will act to substantially weaken Durian. However, the damage and death toll in the Philippine is likely to be great, due to the slow movement of the storm, which will bring long-duration battering winds and extreme rainfall. Already, 9 inches of rain has fallen at Samar Island and 6 inches at Pili as of 3 GMT this morning, and rainfall amounts exceeding 12 inches in the mountainous areas are sure to cause life-threatening flash floods and mudslides all along the track of Durian. One major positive development is the storm's unexpected more westerly track, which is taking it well south of the capital city of Manila, with its 12 million residents. Still, damage and loss of life may rival what devastating Typhoon Xangsane did to the islands on September 27. Xangsane, a Category 4 typhoon that passed over Manilla, killed 218, did over $100 million in damage, and left tens of thousands homeless. Durian is the fourth major typhoon to hit the Philippines this year.


Figure 1. Latest satellite image of Durian from NOAA.


Figure 2. Latest precipitation forecast for a 24-hour period from NOAA's Satellite Analysis Branch.

I'll be back Friday with the latest on Typhoon Durian, plus an analysis of why the 2006 Atlantic hurricane season was so mild.

Jeff Masters