What are the predictions for this year’s hurricane season?
Researchers have been scaling back their estimates on the 2009 Atlantic hurricane season since it started earlier this summer. Past seasons have seen violent storms form seemingly from the very beginning of the potential window for hurricanes — but this year has been terribly quiet.
Too quiet, in fact, for some. Even as I’m writing this, there is an area of interest in the Atlantic ocean — an area of showers and thunderstorms off the Cape Verde islands that shows some potential for turning into a tropical storm within the next few days.
The Colorado State University storm research team, probably the most trusted set of analysts for tropicl activity, has officially reduced its own 2009 Atlantic hurricane season forecast, predicting that only 10 tropical storms will appear in the Atlantic, and that only four of those storms are likely to strengthen into hurricanes.
Interestingly enough, after a string of years featuring nasty storms (Katrina, Rita, Ike, etc) this year is the slowest start to any Atlantic hurricane season since 1992.
The Colorado State forecasting team, founded by famous storm researcher William Gray, made a prediction earlier this summer that the season would see 11 tropical storms, including five hurricanes. While today’s reduction to 10 storms and 4 hurricanes may seem like a small difference, imagine if that one storm lost had been a killer like Katrina.
Tuesday’s forecast revision by Colorado State researchers suggests that only two of the hurricanes would reach the all important “major” status of Category 3 or higher. At Category 3, hurricanes contain sustained winds of over 110 miles per hour. This is the level at which hurricanes begin to do major damage.
Tuesday’s change in the forceast is the third time already this season that Colorado State’s hurricane forecast has been reduced due to sea surface temperatures dipping lower than expected. It is not all that common for the mostly tropical Atlantic Ocean to cool down this much during hurricane season. Some suggest that the development of El Nino conditions in the eastern Pacific may have something to do with the forecast change as well. El Nino is a weather system that cuases the occasional warming of Pacific sea waters that acts to dampen Atlantic hurricane activity by increasing a force known as “wind shear” — wind shear is a severe difference in conflicting wind speeds at differing altitudes. These wind shear forces appear to destroy cyclones at an atmospheric level.
The National Oceanic and Atmospheric Administration, the U.S. government agency in charge of reports on the climate, said in early July that the eastern Pacific had demonstrated El Nino conditions. This meant trouble for the Colorado State researchers who predicted last December that this hurricane season would produce 14 storms, seven of which would reach full hurricane strength. The forecast dropped to 13 storms, including six hurricanes, in April, then again to 12 and 5 this summer.
Strangely enough, the first two months of the current Atlantic season (June and July) have not produced any tropical storms or hurricanes. The season runs through November 30th, but most of the activity in the Atlantic happens long before then. Historically, according to Colorado State researchers, the busiest part of the season is from late August to mid-October.
What does this slow start mean for those who live in the path of potential hurricanes? Going back to the fact this season has been incredibly slow — the last hurricane season that started this slowly was in 1992, the year of Hurricane Andrew.
I don’t say that to scare people, but to remind people that a slow start doesn’t mean a slow ending. “El Nino” is certainly putting a chokehold on the Atlantic storm season, but weather forecasters are now pointing to dry desert air from the Sahara as a potential storm slowing factor.
Those of you in the path of tropical storms and hurricanes, consider yourselves lucky — you’ve been given an extra two months to get ready for this hurricane season. Make sure you are stocked with supplies in case of emergency, and that you have an evacuation plan set with your family and friends.