Reasons for a busy hurricane season

We’re heading into the heart of the hurricane season, and the long-range forecasters at Colorado State University think the rest of the summer and early fall is going to be busy.

CSU forecasters Phil Klotzbach and William Gray upped their earlier predictions for the 2008 hurricane season, which runs from June 1 to November 30. A news release sent out Tuesday by CSU predicts that the rest of the season will be “much more active … than the typical season between 1950 and 2000.” The revised CSU forecast says 17 named tropical storms will form, with nine of those storms developing into hurricanes.

Of those nine hurricanes, five will become major storms with winds exceeding 110 miles an hour. So far this year, five named storms have formed. Two of those storms have become hurricanes, including the mysterious Hurricane Bertha, which unexpectedly intensified into a major storm.

From 1950 to 2000, there was an average of about 10 named storms, six hurricanes and two major hurricanes.

Gray – a pioneer in long-range hurricane season forecasting – and his colleague Klotzbach base their revised estimate on several factors: Unusually warm sea surface temperatures – which could provide energy for developing hurricanes – low pressures at sea level over the tropical Atlantic in June and July, and a lot of activity in the so-called “deep tropics” east of Puerto Rico.

In an interview last month for National Geographic News, Klotzbach told me that when storms start forming east of Puerto Rico early in the summer, it’s a strong indicator that an active hurricane season is likely.

Hurricane Bertha formed off the west coast of Africa near the Cape Verde Islands, a notorious breeding ground for powerful hurricanes. But usually, the Cape Verde monsters don’t start forming until much later in the season. Bertha became a named storm on July 3 – the earliest Cape Verde storm on record.

On July 7, Bertha became a category 1 hurricane when its strongest winds reached 75 miles an hour. The storm wasn’t expected to strengthen much beyond that, but it astonished scientists when its winds cranked up to 115 miles an hour only 12 hours later.

Meteorologists couldn’t explain why Bertha underwent that burst of intensification. But the storm was far out at sea and not threatening any coastline, so hurricane hunter aircraft were not sent out to monitor the storm. Had the hurricane hunters flown into Bertha and gathered more data than was available from satellite monitoring, they may have discovered the reason for its sudden strengthening.

Klotzbach and Gray also think there’s a 67 percent probability that an intense hurricane is likely to make landfall somewhere on the U.S. coast before the season ends in November. That stretch of coastline includes Washington County, North Carolina. And that's, um, where Jane and I live.

The last hurricane to strike Washington County was Hurricane Isabel in September 2003. Although Isabel was a category 2 hurricane when it came ashore, it still packed quite a wallop. The Washington County Emergency Management Department clocked one of Isabel’s gusts at 120 miles an hour in downtown Plymouth when the eye of the storm arrived here.

The photo at the top shows Isabel’s handiwork on Washington Street in Plymouth. I shot it after the winds finally diminished some. That’s an oak tree that was snapped like a stick about seven feet above the ground.

I’m afraid we’re about due for a hurricane here. Of course, I hope I’m wrong.

More information about the Colorado State forecasts is at http://hurricane.atmos.colostate.edu/.

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