It’s what meteorologists at the National Hurricane Center dream of. They don’t get it often. But, when they do, it allows them to breathe a sigh of relief.
Hurricane Dean could quite easily have become like many other Caribbean hurricanes such as Hurricane Ivan (2004), Hurricane Isidore (2002), Hurricane Katrina and Hurricane Rita (both 2005). And early in the forecast period, it appeared to be at least a possibility.
Hurricane Dean, however, should, and most likely will, continue it’s west-northwest track throughout it’s hurricane life, taking it across the treacherous region of the Yucatan and then into Mexico around Tampico by mid-next week. This is entirely thanks to an upper-level low, clearly seen on water vapor imagery, moving westward across the Gulf, and a high pressure ridge building in behind it. The building high is the same one that has steered Dean throughout it’s life.
Hurricane Dean Water Vapor Imagery - Courtesty of Colorado State Tropical RAMSDIS
Most, if not all forecast models are continuing to take the Low west, followed a few days behind by Hurricane Dean. The tracking of this upper-level Low gives forecasters enough time to monitor any changes in the speed of the Low, and thus correctly make changes to their forecast of Hurricane Dean.
With past storms, the situation is generally the same. In most cases, instead of an upper-level Low moving west across the Gulf, it’s a building trough coming in from the western United States. Typically, as in the cases of Hurricanes Ivan, Isidore, Katrina and Rita, the westward moving hurricanes find the western edge of the breaking-down High and begin their turn north. Had Dean been just a little further west of it’s current location, we’d be talking about a landfalling hurricane in the northwestern Gulf of Mexico. It would have all been about timing.
These timing issues can cause significant errors in forecasting. Though the National Hurricane Center may very well be on target as far as forecasting the northward turn, any slight delay or advance of that turn compounded by the degree of the turn can make even a reasonably-accurate forecast off by several dozen miles. These changes compound quickly as the storm progresses. Especially in areas such as the Texas Gulf Coast, or even along the Mid-Atlantic, a slight change in direction by a hurricane can throw the forecasted landfall off by as much as 200 miles.
Instead, the National Hurricane Center is given a dead-on situation. This is a serious hurricane, without a doubt. But it gives an excellent trial run for the forecasters. They can test their skills against the computer models. The Air Force and NOAA personnel flying the reconnaissance get any errors or equipment malfunctions out of the way as they fly into one of the most powerful hurricanes to develop in the Atlantic. Government officials from Louisiana to Mexico to the Lesser Antilles run through their procedures for an oncoming hurricane.
Residents in Texas and Louisiana will breathe easily knowing they have avoided such a potentially catastrophic hurricane. Houston residents will relax knowing they will not, at least this week, see a mass evacuation of millions as they did as Hurricane Rita approached.
Residents, however, in Jamaica, Cayman Island, Cozumel, and Mexico will continue preparations until the time approaches that the wind begins howling and the rains begin falling. Then they will seek their shelter; a place they had decided perhaps as much as five days prior they would go if Hurricane Dean visited them.
When the preliminary report on Hurricane Dean emerges, the National Hurricane Center will talk about forecast errors and how they were off by so many miles at different time intervals. But, in general, they were right on with the target. And residents knew and had time to prepare. And ultimately, that is what’s most important.
