The waiting has begun on Gustav with the system looking quite ragged this afternoon. In fact, hurricane hunters this evening found no more than 39 knot winds at flight level with sustained winds lowered to 45mph as of the 700pm bulletin. But as this system drifts farther to the west a slow re-strengthening process will likely begin. Per the National Hurricane Center, Gustav will regain hurricane status by Friday with the system heading into very warm waters and a low wind shear environment. Therefore the possibility of Gustav becoming a major storm is still in the mix. The forecast track continues to be quiet similar as the past several days (but a little farther to the east and on the eastern side of most of the models) with the intensity forecasts not quite as aggressive as they were yesterday as the hurricane models have backed off a bit as well.Nonetheless all of coastal Louisiana is in the “cone of uncertainty” 5 days out.
The cone represents the average track error given any forecast period. Although the NHC’s average track error has improved over the last several years the long-term averages for radius of errors are as follows: 12 hour – 46 miles, 24 hour – 81 miles, 36 hour - 115 miles, 48 hour – 147 miles, 72 hour – 216 miles, 96 hour – 266 miles, 120 hour – 350 miles. So although the “official” track puts the center of circulation of Gustav just of the southeast coast of Louisiana the final path could be as far off as the Florida Panhandle or back to the upper Texas Coast. This is why we shouldn’t pay as much attention to the line, but follow the cone more closely.Acadiana is in the “cone” of uncertainty 4-5 days down the road and the uncertainty remains rather high.The latest wrinkle this evening is the possibility of a blocking ridge that may develop over the Southeast U.S. by early next week. The near-term steering influences associated with Gustav will be the ridge of high pressure to the north of the system that will initially push Gustav westward, a subtle weakness in the Gulf of Mexico (left behind from Fay) and then another ridge that will be building over the south-central U.S. by early next week. The big question this weekend and beyond will be whether Gustav will find a path of least resistance between the two aforementioned ridges or if they “bridge” with one another and allow for Gustav to stall prior to landfall with a push or drift to the west. The bottom line is that we’ll likely be talking about this system at least for another week. Be patient, be ready, and stay tuned.