July 23rd, 2010
06:23 PM ET

Louisiana's invisible shield: wind shear

Bonnie is currently making its way across the Florida peninsula, and is set to enter the Gulf of Mexico on Friday night. When it does so, it will encounter some of the warmest waters the Gulf has ever seen – and in some places even warmer than the waters that Katrina crossed over in 2005. So what’s the difference between Bonnie and Katrina? It's all in the upper levels.

Over the past few days, CNN Hurricane Headquarters has been monitoring an area of low pressure at the top of the troposphere, which is the place where all the weather happens in Earth's atmosphere. Tropical cyclones (the generic term we use for tropical depressions, tropical storms, and hurricanes) thrive in "low-wind" environmental conditions. This sounds counter-intuitive but it makes sense when you think about it. Strong winds in the environment where the tropical cyclone seed is trying to grow is going to rip it apart. We call this "wind shear," and it literally shears a storm apart. A tropical cyclone seed needs to plant its roots in weak winds and warm waters so it can build the vertical structure that it needs to churn into a hurricane.

The upper-level low that we have been monitoring is causing some strong wind shear over the Gulf of Mexico, and its why we didn’t see Bonnie strengthen when it was over the Bahamas, and it’s going to prevent strengthening over the Gulf of Mexico as well, assuming the wind shear sticks around. So even though the main ingredient for a strong hurricane is present (warm sea surface temperatures), we probably won’t see Bonnie strengthen much past 50 mph wind speeds.

The northern Gulf will still see relatively strong winds, especially over the Deepwater Horizon site, but it won’t be the worst case scenario: a major hurricane rolling into Louisiana with catastrophic impacts to the oil spill clean up effort.

And we shouldn’t take Louisiana’s Invisible Shield for granted though, because as the season rolls on, the wind shear tends to decrease. We can’t be sure the Gulf will be as lucky next time.

soundoff (2 Responses)
  1. P.Kaplan

    Why were there no super tankers syphoning oil off the surface water immediately following the leak?

    Why did the Obama administration refuse super tanker help from 11 other nations 200 million gallons ago?

    Why does Obama only go to the Gulf when the press guilts him for not being there enough?

    Why were Louisiana's attempt to block their coastal marshes with barges held up for a week by Washington?

    Why did the Coast Guard hold up the barges another day for lack of sufficient life jackets where the water is 2 feet deep at low tide?

    Why is there a FAA temporary flight restriction over the spill area?

    Why doesn't BP drill an independent well in the same oil resevoir near the damaged one and use the oil revenues to fund the cleanup costs? Wouldn't this relieve the 6-7000 psi off the damaged well?

    Why did the MMS not require annual operational checks on blowout preventers?

    Why did Obama want to shut down all drilling rigs for 6 months when the only serious threat are from deep water wells?

    Could it be that the Obama administration would interfere with BP's efforts to kill this well quickly in order to advance it's policy against any off-shore drilling?

    Why does Obama preach energy conservation and fly around in Air Force One every other day?

    Why did the EPA condone BP's use of dispersants which are more harmful than oil pooled on the surface?

    Don't most fish swim in the water where the dispersants are suspended?

    Why did no one listen to Shell Oil's ex-president John Hofmeister when he said on CNN that he would surround the well with super tankers and pump the oil onboard before it spread all over the Gulf?

    Why is it that the public perception of BP is that they could care less about the ecological damage to the water, animals and fish that live in the Gulf?

    Why did retired Admiral That Allen seem to take pleasure in telling us that BP will probably have to
    resume dumping oil back into the Gulf?

    Why can't BP simply hook up syphon hoses from the shutoff to containment vessels beforehand in the event they must relieve well pressure?

    Why doesn't That Allen really retire and go away?

    Why has no one from the press, nor the U.S. government ever truthfully answered these questions?

    July 24, 2010 at 2:38 pm | Report abuse |
  2. Jamie Larue

    Why don't most people know that without oil over 60% of things they use every day would disappear?

    July 24, 2010 at 11:17 pm | Report abuse |