Tropical development chances trending higher for Gulf & Atlantic disturbances

Tropical development chances trending higher for Gulf & Atlantic disturbances
Special Tropical Weather Outlook issued by the National Hurricane Center at 10 a.m. Tuesday. An area of low pressure located midway between Africa and the Lesser Antilles was given an 80% chance of development. (Source: WAFB)

BATON ROUGE, La. (WAFB) - A tropical wave in the Gulf of Mexico approaching the southeastern Gulf Coast of the U.S. has a medium chance of development, according to a special tropical weather outlook issued at 10 a.m. Tuesday by the National Hurricane Center (NHC).

Special Tropical Weather Outlook issued by the National Hurricane Center at 10 a.m. Tuesday. A tropical wave entering the Gulf is given a 40% chance of development.
Special Tropical Weather Outlook issued by the National Hurricane Center at 10 a.m. Tuesday. A tropical wave entering the Gulf is given a 40% chance of development. (Source: WAFB)

Development chances are now placed at 40% by NHC, a doubling of the 20% probability given to the system on Monday. A Hurricane Hunter airplane was scheduled to investigate the system this afternoon, but that flight has been canceled with no signs of significant organization noted yet.

Chances of a tropical depression forming between now and 7 p.m. Thursday via the European model ensembles. The map indicates a better than 80% chance as of the 7 p.m. Monday model run.
Chances of a tropical depression forming between now and 7 p.m. Thursday via the European model ensembles. The map indicates a better than 80% chance as of the 7 p.m. Monday model run. (Source: Weathermodels.com)

Meanwhile, the European model and its associated ensembles remain even more bullish on possible development. Last night’s ensemble runs showed better than an 80% chance of a tropical depression forming in the northern Gulf by late Thursday.

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However, the same ensemble guidance indicates little to no chance that the system strengthens into a tropical storm, so the expectation is that whatever becomes of this disturbance should stay on the weaker side, with rain being the primary impact.

RPM model forecast valid 2 p.m. Thursday showing the tropical wave and potential area of low pressure passing south of Louisiana.
RPM model forecast valid 2 p.m. Thursday showing the tropical wave and potential area of low pressure passing south of Louisiana. (Source: WAFB)

While rain is expected to be the primary impact, most of our guidance keeps local rain totals manageable through the weekend. The Euro only generates an inch or less of rainfall from Baton Rouge northward, one inch to two inches south of Baton Rouge, and some totals in the two-inch to three-inch range right along the coast.

The forecast rainfall map from the Euro clues you into the expected track, with heavier rains expected just offshore of Louisiana and eventually moving into parts of Texas. Obviously, we’ll still want to pay attention since any northward deviation in the track could bring higher rain totals into our area.

Forecast rainfall from the European model through 7 p.m. Sunday.
Forecast rainfall from the European model through 7 p.m. Sunday. (Source: WAFB)

Primary local impacts will be on Thursday, July 23 and Friday, July 24. Rain will be likely on Thursday as the tropical wave and/or area of low pressure passes a little south of our coastline. It should move into Texas by Friday, but a broad expanse of moisture on its eastern side and a strong onshore flow from the Gulf of Mexico should keep rain chances at 70% or better.

Finally, we have another area in the tropics that merits some attention today. An area of low pressure about midway between Africa and the Lesser Antilles is now given an 80% chance of development over the next couple of days.

The system has continued to show signs of organization over the last 24 hours and could become a tropical depression at any time. However, by the time it approaches the Lesser Antilles and the Caribbean later in the week, conditions are expected to become more hostile and it may not survive into the Caribbean Sea.

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