Weather Nerd

Gustav almost a hurricane; track shifting left

The National Hurricane Center has bumped Tropical Storm Gustav’s estimated maximum sustained winds up to 70 mph as of 11pm EDT, and the discussion states bluntly that “THE NEXT AIRCRAFT AT [2:00 AM EDT] WILL MOST LIKELY FIND A HURRICANE.”

Meanwhile, the official forecast track has shifted southward somewhat, and yet “MOST OF THE PRIMARY [COMPUTER MODEL] GUIDANCE IS EVEN FARTHER SOUTH.” (You can see that for yourself here: the thick red line is the NHC forecast; most of the models are to its left.)

Translation: unless the models shift back to the right (i.e., north), the official forecast track will likely continue trending even further leftward over the next couple of advisories, to the point where Gustav will soon be formally expected to miss Cuba entirely, or almost entirely. This largely validates Alan Sullivan’s observations, mentioned in my previous post. Bottom line, Gustav is looking more and more like a potential, eventual threat to the central or western Gulf — not just Florida.

How strong will Gustav get? As with T.S. Fay, the track forecast is crucial to the intensity forecast. Gustav’s predicted peak intensity has been nudged upward as of 11pm, to 90 mph, precisely because the official track now calls for the storm to spend less time over land and more over water. And again, the discussion acknowledges that this is still more conservative than some of the most trusted models: “BOTH THE GFDL AND THE HWRF SHOW GUSTAV AVOIDING NEARLY ALL OF CUBA AND HAVE GUSTAV AS A MAJOR HURRICANE IN FIVE DAYS.”

As I noted earlier, Alan Sullivan — frequently an outspoken critic of hurricane “hype” — is bullish on Gustav’s prospects, predicting that it will become a Category 4 or 5 hurricane “in a few days,” if its “core stays over open water south of Cuba.” Dr. Jeff Masters, for his part, says “the potential for rapid intensification exists should the center stay more than 50 miles from the Cuban coast.” And those conditions precedent appear increasingly likely to occur.

Yikes. Stay tuned, as they say.