Tropical Storm Ida – Thu update

…Tropical Storm Ida has formed in the Carribbean as of 420 pm CDT…

The first significant Gulf of Mexico tropical cyclone of the year is forming in the Carribbean, SE of the Cayman Islands and south of Cuba. USAF hurricane hunters recently found higher winds on the eastern side of the system, and the official 5 pm EDT information from the NHC was updated at 520 pm EDT. Winds are currently 40 mph, and the storm is moving NW at 14 mph.

As shown in the above satellite image, the tropical storm is still not well-organized, with most of the thunderstorms (that release the latent heat that cause the pressure at the surface to drop…more in a blog later) NE of the center. However, with relatively light wind shear, the system should stay mainly vertical, and with warm water temperatures in the area near western Cuba, Ida will slowly intensify through tomorrow, when it is expected to be a strong tropical storm (winds 60-70 mph).

On a NW path, the storm will slowly intensify, with a brief lull over Cuba tomorrow, then it should become a hurricane over the Gulf of Mexico as it gets into the “Gulf Loop Current”, an area of extra water water in the central Gulf (water temps around 31 C, or 88 F). It looks like it will encounter weak wind shear across the Gulf, and get into the warmest water near the coast, so it has the potential to become a major hurricane, maybe Cat 2 with winds over 100 mph, by the time it makes landfall late on Sunday.

Hurricanes tend to follow the path of least resistance to go north. Looking at upper-level winds now, a strong ridge in the western Atlantic is keeping the storm moving NW, and that ridge will build into the Carolinas over the weekend, likely keeping the storm moving more toward TX/LA/MS, and less toward AL/Fl. However, a storm in the early stages still has extra uncertainty because getting an exact fix on the center is difficult.

(pivotalweather.com)

Note in the “spaghetti plot” of hurricane model tracks below, there is fairly good agreement in a landfall Tuesday evening south of New Orleans, then a move up through Mississippi on Monday. There could still be shifts in the track over the next couple of days.

Impacts for Alabama: It is too early to tell what kind of structure the storm will have. We should be on the east side of the track, so very moist air will be pushed into Alabama from the Gulf of Mexico Monday and Tuesday, with the possibility of thunderstorms producing more heavy rain (after one of the rainiest summers in a long time). As far as the Alabama Gulf Coast, unless there is a significant change in the position of the upper-level high pressure areas, the center of the hurricane should stay away. However, on the east side, there will still be winds 35 to 70 mph, along with heavy rain and maybe storm surge. It is too early to tell about that either…but main impacts should be Sunday and Monday at the Alabama coast.

We will post another update on Ida tomorrow afternoon, and over the weekend. UAH is sending two mobile instrumented vehicles, and several people, to Louisiana this weekend to get data in Ida. I will keep you posted on their activities, also.

Dr. Tim Coleman

Consulting Meteorologist

Coleman Knupp and Dice LLC

ckdweather.com

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