Disorganized storm a threat to Gulf spill area
By Jim Bradshaw
AL 93, the tropical disturbance in the central Caribbean, remained little more than a disorganized mess of storms Thursday morning, but still has a chance to organize itself into Tropical Storm Alex and run disastrously into the middle of the Gulf oil spill.
Satellite imagery showed the storm split into two parts. This will make it harder for the system to develop since there is no center point for it to organize around.
Importantly, intensity models have backed off considerably from where they were two days ago when some of them were projecting a Category 2 or 3 hurricane within a few days.
Now, they are are in general agreement that the system will barely reach tropical storm intensity, if at all. The National Hurricane Center is giving the storm a thirty percent chance of developing into a tropical depression sometime tomorrow.
Accuweather.com meteorologists give the storm “a good chance” of developing into a depression Friday or Friday night and then strengthening into a tropical storm on Saturday. There is only the slightest possibility under current projections that the storm will reach hurricane strength.
A disturbance becomes a tropical depression when a distinct pattern of circulation can be seen and sustained wind speeds are 38 miles per hour or less. Disturbances become tropical storms and are given names when they reach a sustained wind speed of 39 mph. Tropical storms become hurricanes when sustained winds reach 74 mph.
Whatever develops, however, Louisiana and the oil spill off its coast are now at the center of its projected path. The ridge of high pressure that was protecting Louisiana has begun to slide to the east. This means that the storm (if it gets itself organized) will head more for Louisiana or the central Gulf Coast, rather than the Texas coast as forecasters were predicting a couple of days ago.
This shift in path could bring higher tides and onshore winds along the eastern half of the Gulf of Mexico. This would create a nightmare scenario of a tropical system pushing oil-laden water onto beaches from Louisiana to Florida.
Upper-level forecast maps show high pressure developing over New Mexico and Texas along with a low pressure trough over the Ohio. This would support a turn to the north for the storm should it organize and enter the Gulf of Mexico. But this scenario would probably result also in increasing wind shear levels over the Gulf which tend to hinder the storm development.
Forecasters emphasize that none of this is certainty. The storm is still too far away and too disorganized to do much more than guestimate what will happen.
“We are still guessing,” said Michael Griffin of the Lake Charles office of the National Weather Service. “We have nothing to pinpoint where it will go. Right now it is a guessing game.”
AccuWeather meteorologists agree: “Since the system has not developed a low-level circulation, computer models are going to be highly misleading until that happens.”
As of Thursday morning the system was moving along the northern edge of a zone of low and decreasing wind shear. This increases the possibility of development over the next couple of days until it runs into the wind shear. Hot water temperatures in the Gulf could also help to energize the storm.
Forecasters should have a better idea of what the system might do by Friday, when it should be in the western Caribbean.
Since 2004, eight tropical storms and seven hurricanes have swirled through the same area as the BP oil spill. In the same period, a total of 92 named storms have emerged.
Some experts, including those at the National Oceanic and Atmospheric Administration – which oversees the hurricane center – have detailed the possible consequences of a hurricane moving into the Gulf later in the storm season.
NOAA said the oil would have little or no influence on a hurricane's strength or track, as such storms are too large and powerful. The agency said oil likely would pushed ashore, but how much and where would depend on the storm's size, strength and the angle it approaches the slick. A hurricane passing to the west of the slick likely would drive oil to the coast, as a hurricane's winds rotate counter-clockwise. If a storm passes to the east, the oil likely would be pulled away from the coast, NOAA said.
Jeff Masters, chief meteorologist of Weather Underground, an online weather site, paints a much bleaker picture.
f a hurricane hits that area of the Gulf and then strikes land, high winds and storm surge likely would carry the oil far inland and coat an expansive stretch of shoreline, he said. Masters, who has been following the Gulf disaster in his blog, said winds alone could deliver oil to hundreds of square miles that otherwise might not be affected,
That was seen in the Exxon Valdez disaster in March 1989. Crews were initially able to contain the tanker spill with booms until a powerful storm roared in with 70 mph winds, he said.
On the optimistic side, Tulane professor Alex Kolker says that under the right conditions a big storm could break the oil spill up into smaller parts and make it easier for natural and physical processes to break it down.
A hurricane could stop oil-capture efforts and delay drilling of relief wells by 10 days, U.S. Coast Guard Admiral Thad Allen, the government’s national incident commander, said yesterday at a press conference in Washington. Rig crews would need to begin preparing to evacuate three to seven days ahead of the storm, Allen said.