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Posted at 12:15 PM ET, 09/01/2011

Hurricane Katia continues westbound; Gulf system poses major flooding risk

Watch: Video discussion with Hurricane Expert Greg Postel


Satellite image showing Hurricane Katia on the bottom right and an area of disturbed weather in the east central of Mexico which may become tropical storm Lee over the Labor Day weekend. (NOAA)

Still more than a thousand miles east of the Leeward islands, Hurricane Katia continues a steady march towards the western Atlantic. Of more immediate concern, perhaps, is an area of disturbed weather in the east central Gulf of Mexico which could be a massive rainmaker for portions of the U.S. Gulf coast.

Gulf system (to be tropical storm Lee?)

Currently a disorganized area of heavy thunderstorms, the National Hurricane Center (NHC) states there is a 70% chance the Gulf of Mexico disturbance (93L) will develop into tropical depression 13 or tropical storm Lee in the next 48 hours.

The steering currents for this Gulf disturbance are very weak. As a result, track models suggest the system will meander in close proximity to the central to western Gulf coast, potentially dumping copious amounts of rain.


Forecast models show the area of disturbed weather, which may become tropical storm Lee, meandering for several days offshore the coast of Louisiana and Texas. (NCAR)

NOAA’s Hydrometeorological Prediction Center predicts extraordinarily high rainfall totals over the Labor Day weekend across the central Gulf Coast.
For example, NOAA’s Hydrometeorological Prediction Center predicts 10-20 inches of rain from the coast of central Louisiana through New Orleans and into coastal Alabama, including Mobile through Tuesday. However, as there is a large amount of scatter in the track forecast, the exact timing and location of the heaviest rainfall is uncertain. A beneficial solution would be if the system drifted towards the Texas coast, offering relief to the drought conditions. However, that scenario is somewhat of an outlier.

Residents along the Gulf Coast should pay very close attention to the forecast for the system which is bound to be among the more challenging. Serious flooding is a possibility in certain locations.

By mid-to-late next week, some of the moisture from this system could sneak into the Tennessee Valley, southeast and mid-Atlantic.

Hurricane Katia

Moderate wind shear and some dry air have stunted Katia’s intensification since it became a hurricane last night. However, strengthening is forecast to gradually resume as the shear relaxes. The National Hurricane Center projects its current sustained winds of 75 mph will grow as high as 120 mph in four days. Note that intensity forecast errors may be large, however.

Track models continue to suggest Katia will get picked up by an upper level trough exiting the East Coast mid-to-late next week recurving it out to sea. However, if this trough is weaker than forecast and passes over it, Katia could then flirt with the U.S. coast. We will watch this closely.

Watch CWG Dr. Greg Postel’s live chat on the tropics below...

By  |  12:15 PM ET, 09/01/2011

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