Breaking news: the Republican Party may postpone its convention, depending on what Tropical Storm Gustav does, according to Fox News.

Postponing the convention for Gustav is a problematic option, considering there could potentially be a succession of hurricane threats to the U.S. in the next few weeks. If you postpone the convention because of Hurricane Gustav hitting the Gulf, what happens if the rescheduled convention runs into a threat from, say, Hurricane Hannah or Hurricane Ike? It promises to be a busy couple of weeks for hurricanes, and presumably the GOP wants to formally nominate McCain at some point in September. Just saying.

Anyway, the 5:00 PM EDT advisory on Tropical Storm Gustav is out, and the headline remains: we just don’t know what’s going to happen. A couple of key quotes from the discussion:

THE CENTER OF GUSTAV MADE LANDFALL ALONG THE EASTERN TIP OF JAMAICA AT ABOUT [2:00 PM EDT] … FLIGHT-LEVEL WIND SPEEDS INDICATED THAT GUSTAV WAS RIGHT NEAR THE THRESHOLD BETWEEN TROPICAL STORM AND HURRICANE INTENSITY…BUT THE DATA WERE NOT QUITE CONVINCING ENOUGH TO INCREASE THE INTENSITY . . .

A LITTLE WEAKENING IS FORECAST IN THE SHORT TERM AS GUSTAV INTERACTS WITH LAND…BUT ONCE IT EMERGES OVER THE OPEN WATERS OF THE NORTHWESTERN CARIBBEAN BY TOMORROW…CONDITIONS APPEAR RATHER FAVORABLE FOR STRENGTHENING. DUE TO THE VERY WARM WATERS SOUTH OF CUBA…COMBINED WITH ANTICYCLONIC FLOW ALOFT…IT IS POSSIBLE THAT GUSTAV COULD RAPIDLY INTENSIFY AT SOME POINT WITHIN THE NEXT COUPLE OF DAYS…ALTHOUGH THAT IS NOT EXPLICITLY SHOWN IN THE OFFICIAL FORECAST. . . .

GUSTAV COULD REACH MAJOR HURRICANE STATUS WITHIN A FEW DAYS…AS FORECAST BY ESSENTIALLY ALL AVAILABLE INTENSITY GUIDANCE. . . .

IT IS SIMPLY IMPOSSIBLE TO DETERMINE EXACTLY WHERE AND WHEN GUSTAV WILL MAKE FINAL LANDFALL. IN FACT…TAKING INTO ACCOUNT THE UNCERTAINTIES IN TRACK…INTENSITY…AND SIZE FORECASTS…THE CHANCES OF HURRICANE-FORCE WINDS WITHIN THE NEXT FIVE DAYS ARE ESSENTIALLY THE SAME AT EACH INDIVIDUAL LOCATION FROM THE FLORIDA PANHANDLE COAST WESTWARD THROUGH THE ENTIRE COASTLINE OF LOUISIANA.

Meanwhile, Alan Sullivan writes about the “traffic jam in the tropics”:

There is usually a burst of Atlantic hurricane activity in early September — a very distinct peak to the season. . . . We are certainly commencing a burst with Gustav and Hanna. There are also two tropical waves with potential for development in the eastern Atlantic, and a tropical low trying to form in the Bay of Campeche. The latter could interact with Gustav. Its outflow is already pluming toward Yucatan, and it could prove to be an adverse influence for Gustav if it persists – sending a shot of northwesterly headwinds at high level toward the NW Caribbean. The more this system organizes, the greater its potential to exert at least some suppressive effect on the other.

As the satellite loops show vividly, Gustav continues to pummel Jamaica. Its forward movement is extremely slow. The two systems to Gustav’s east, the TUTT low and Hanna, are also scarcely moving. There’s a traffic jam in the tropics, with numerous disturbances trying to gain control of a very muddled upper level wind pattern. It’s absolutely fascinating to behold.

Dr. Jeff Masters has also posted a new, full update.