Ernesto and Florence

As though the Atlantic knew what month we started, the tropics came alive this week. We now have two tropical storms, Ernesto in the Caribbean and Florence in the far eastern Atlantic. The former storm may become a Gulf coast threat later in the week, while Florence may flounder in the Atlantic with an eventual track towards the U.S. east coast in about a week.

Tropical Storm Ernesto

Infrared satellite image of Tropical Storm Ernesto valid at 3:20 am on 08/05/12.

As you can see in the image above, Ernesto does not look too impressive this morning. Dry air to the north and west has been entrained into the storm, limiting deep thunderstorm activity. This isn’t necessarily a sign of long-term weakening, but will limit the storm’s ability to strengthen heading into Sunday. Environmental conditions will improve once Ernesto gets to the Western Caribbean, so the Yucatan Peninsula and Belize need to be aware that a hurricane could be bearing down on them early in the week.

06z 08/05/12 track guidance for TS Ernesto.

The early morning track guidance for Ernesto shows two main clusters. One cluster moves Ernesto into Belize, while a second cluster moves Ernesto towards the Yucatan, but south of Cancun and Cozumel. The latter cluster is most likely due to the models having a stronger storm, while the former cluster is due to a weaker storm. The northern cluster will be more of a concern to interests in TX.

06z 08/05/12 intensity guidance for TS Ernesto.

The early morning intensity guidance above shows us that a few models think Ernesto could strengthen to a hurricane in the next 48-72 hours. Depending on how well the storm fights off the dry air, this forecast could be conservative as the ocean heat content and shear will be very favorable in the Western Caribbean.

My forecast is for a Category 1 hurricane moving towards the Yucatan by late Tuesday night with a decent hurricane threatening south Texas to northern Mexico by Friday or Saturday. For the time being, I think the northern Gulf Coast is safe, but this may change as the pattern in the U.S. is in transition this week.

Tropical Storm Florence

Infrared satellite image of TS Florence in the far eastern Atlantic valid at 3:35 am on 08/05/12.
06z 08/05/12 track guidance for TS Florence.

Tropical Storm Florence will not be a big concern for the U.S. over the next week. The storm quickly intensified in the last 24 hours and now exhibits a compact, central dense overcast (CDO) which usually means the storm has strengthened. As of this writing, the estimated strength is 60 mph, but weakening is likely over the next few days due to lower sea surface temperatures and dry air. The weaker Florence remains, the higher likelihood of the storm getting back far enough west to raise concern on the East Coast. While this is only a very slight chance at this point, I think it’s worth mentioning as this storm should not be ignored. The track guidance above again shows two main clusters. . .a northern cluster with less skillful models and a southern cluster which shows a more westward direction.

My forecast for Florence is to remain a tropical storm through the next 4 days with possible weakening as the storm encounters hostile environmental conditions. I think the storm gets back far enough west to threaten Bermuda with a possible run at the East Coast the week of 8/13.

Thanks for reading!

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