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Tropical storm Isaac and the latest track projections

Posted by David Epstein  August 23, 2012 03:40 PM

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Currently, the latest track projection for Isaac takes the storm a bit further west late this weekend and early next week. However, we must be careful about thinking Florida is in the clear based on one new projection. The forecast for this storm will change multiple times in the next two days. Tropical storms and hurricanes tend to impact areas even if they don't hit them directly. Although the storm is still several days away from any possible landfall in the United States the prognosticators and pundits are out in force with what the storm may mean for Florida and the Republican National Convention which begins Monday in Tampa. Issac is still a tropical storm and is forecast to briefly reach hurricane strength before hitting Hispaniola and Cuba. Those islands have a lot of mountainous terrain. This is an important fact because if the core of the storm went over the islands the mountains and land mass in general interferes with the storms development. Isaac would dramatically weaken from this interaction and the storm would then be downgraded to a tropical storm again. The big question after that is will the storm re-strengthen into a hurricane before hitting or passing near the Florida peninsula? I'll be updating my latest thinking about Isaac on Twitter at @growingwisdom

The track
Issac5am.gif
Right now the storm is forecast to move over and and through parts of the Dominican Republic, Haiti and Cuba tomorrow and early Saturday. After that the storm will move near the Florida Keys and then is forecast to move northwest along the western coast of that State. The good news is that the storm is still not forecast to become a major hurricane at any point. The latest track takes the storm to the west of Tampa and keeps the strongest part of the storm over the ocean. You can be sure that the attention this storm is going to receive will be exponentially larger than the actually storm. In our twitterized world, every radar image, satellite photo and new track will be analyzed and reanalyzed 100 times over. Remember, the track of these storms can change dramatically. Although the storm is forecast to ride along the west coast of Florida today, the track could also shift east and impact the east coast of Florida and points north. It's quite rare for a storm to directly hit Tampa and I suspect the track will indeed shift multiple times next couple of days.
Isaac tracks.gif

Why do hurricanes form?
cyclone_map_thumb.en.gif
You might wonder why these storms form in the first place. I tell my students that hurricanes are nature's way of moving excess heat from the tropics to the northern latitudes. From about June through October, the oceans in the tropics are very warm. The water temperatures must be in the 80s not only at the surface but several feet below as well. This temperature structure to the sea only happens in the warm months. As the sun evaporates the ocean water that warm moist air rises and can, if conditions are favorable, create thunderstorms. In some cases, these clusters of thunderstorms will group together and begin to rotate. The rotation can be attributed to something called the Coriolis force. The Coriolis is strongest at the poles and zero at the equator. This is why hurricanes don't happen on or within several hundred miles of the equator. (no Coriolis=no spin) Winds inside the thunderstorms stir up more ocean spray which then evaporates and continues to feed the storms. If the winds reach 39 mph, the storm is called a "tropical storm." And when the wind speeds reach 74 mph, the storm is officially a "tropical cyclone," or hurricane. cat 5 hurricane.bmp Once the storm becomes a hurricane they are then categorized into 5 different levels of strength. Category 5 is the strongest and the last time one of those actually hit the United States was in 1992 when hurricane Andrew came ashore south of Miami.

Gardening tip this week

This is a great time of year to plant. I actually feel that for many plants fall is a better time to plant than it is in the spring. Since the ground stays warm well into October, roots have a good chance to become established. When you plant in the spring, much of the energy of the plant goes into making new leaves, not new roots.
If you have a tough spot that you can't seem to grow anything, check out this video and learn about some of the plants that actually thrive in hard to grow conditions.

I'd love to hear your thoughts on this blog or any others. Please follow me on Twitter at @growingwisdom and check out my latest videos at GrowingWisdom.com

This blog is not written or edited by Boston.com or the Boston Globe.
The author is solely responsible for the content.

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About the author

David Epstein has been a professional meteorologist and horticulturalist for three decades. David spent 16 years at WCVB in Boston and currently freelances for WGME in Portland, ME. In 2006, More »
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