Convention hurricane chances climb

All that supposedly far-fetched talk about a hurricane impacting the Republican National Convention in Tampa isn't so far-fetched any more.

And Democrats eager to smirk at the Republicans shouldn't be so smug, because the chances of tropical systems having an impact on the DNC in Charlotte are not zero either.

The main culprit (there are two, really, but we'll get to the second later) is Tropical Depression 9, which likely will become Tropical Storm Isaac within 24 hours. Late Tuesday morning, it was several hundred miles east of the Lesser Antilles, with 35 mph top winds, and trying to get its act together.

The National Hurricane Center says tropical storm warnings are in effect for the Lesser Antilles -- islands like Martinique, St. Martin, Antigua, Anguilla -- with winds of 40 to 50 mph possible as Isaac passes through on Wednesday.

A tropical storm watch is in effect for Puerto Rico and both the U.S. and British Virgin Islands.

The official NHC forecast calls for Isaac to pass south of Puerto Rico, but close enough to deliver heavy rain and strong winds. It is predicted to be a 60 mph tropical storm at that point, then grow to a hurricane by the time it passes a short distance south of the Dominican Republic and Haiti.

By 11 a.m. Saturday, Isaac is forecast to be a 105 mph hurricane, preparing to cross the center of Cuba on a northwest track toward ... the United States, one would assume, although the Hurricane Center's forecast only goes out for five days.

The major computer models, with their seven-day predictions, take Isaac somewhere near Florida next Monday and Tuesday. Some models call for the storm to move up the Gulf Coast, others up the Atlantic side, and others predict a direct hit. There are other models that show a more southerly track, into the Gulf of Mexico.

This is a big deal, of course, because the Republican National Convention is in Tampa next week.

Jeff Masters, a tropical weather specialist (www.wunderground.com), wrote in his blog Tuesday morning that this season's trend is for tropical systems to remain south, which would steer Isaac into the Yucatan Peninsula of Mexico or into the Gulf.  However, he said that if a low pressure system now in western Canada moves into place across the East, it would create a weakness in the atmosphere and allow Isaac to curve northward into Florida.

Republican Party officials say they've planned for a possible hurricane, but it obviously would cause major disruptions.

Why should Democratic Party officials worry about Isaac for Charlotte?  Realistically, the system would have pushed north of the Carolinas by the time the convention starts on Labor Day weekend. But if Isaac were to curve north into Florida, and if its track were to slow by 24 hours or so, the remnants of the storm -- flooding rains, tornadoes -- could impact the inland Carolinas by late in the week leading up to the convention. A number of outdoor convention-related preview events are scheduled that weekend.

(Time for a reminder to Charlotte-area residents ... dying tropical storms are much more of a threat to us than the thriving systems.  Hurricanes die when they reach land, but their remnant heavy rains and tornado-causing wind shear remain intact far inland.)

I know, there are a ton of IF'S here.  But, as Masters noted, he originally predicted a 0.2% chance of a hurricane interrupting the Republican National Convention. Now the chances are 1 to 3%.

THAT SECOND THING ... There's another area of disturbed weather in the Atlantic, about a thousand miles east of Tropical Depression 9. Right now, it's designated as 96L, but indications are that it also will become a named storm (Joyce) in a few days. In fact, its circulation is better formed than Tropical Depression 9's.

Most computer models call for 96L to curve northwest and then north, into the open Atlantic.

But the southern-most predicted paths would bring the system on a course headed for the Southeast coast.

Stay tuned.