Dangerous hurricane forecasted into the north-central Gulf of Mexico late this weekend.


Current:


Gustav has finally emerged off the SW coast of Haiti…and has turned toward the WNW per recon fixes. In fact the forward motion has slowed greatly and is less than 5mph as Gustav has yet to become caught in the faster steering of the ridge over FL. The high mountains of SW Haiti have disrupted the small inner core and the system has weakened to a 60mph TS with surface pressure of 996mb and winds of 40-45kts at the surface per the aircraft.


Track:


Per mid and upper level steering…showing a strong high pressure ridge over FL which Gustav should get caught within the southern part of this high within the next several hours and begin a westward motion. CMISS data shows this high centered over S FL ridging SW into the NW Caribbean. While the available model guidance does not suggest a WSW or SW motion…based on the position of this high such a motion is possible. The GFS continues to be trash…a far eastern outlier with a track along the N Cuban coast…which is highly unlikely. The GFS along with the NOGAPS make up the eastern side of the guidance envelop with the GFDL and HWRF nearly on top of each other down the middle and the EURO and CMC off to the western side of the clustering. It should be noted that the GFDL continues wide swings between model runs while both the CMC and GFS have been more stable…but are far outliers to either side.


For the short term a track toward the W or even WSW seems most likely as Gustav rounds the south side of the ridge over S FL. By late Friday into Saturday Gustav will begin to reach the SW side of this ridge and begin to turn toward the WNW and NW. At this time a new high pressure ridge will be building across the SE US and this high will be the controlling factor in determining Gustav’s final landfall location. Do not think the GFS weakness it is showing over the SE US will be a factor and this is why the GFS continues its strong right runs…and of a much weaker system.


Through 72 hours the forecast is fairly straight forward with a track toward the NW Caribbean Sea….thereafter the uncertainty increases to the point that the entire error cone would be at risk. At this point, extrapolation of the centerline NHC track is highly discouraged given the spread in the respected global guidance and the noted errors of TC forecasting at days 4 and 5. Equal and similar preparations should be made within the entire error cone from TX to the FL panhandle.


Intensity:


While Gustav has weakened due to land interactions…the system is now back over the warm waters with favorable upper level winds aloft. While the tiny inner core was disrupted, it should slowly rebuild itself as the cyclone tracks off toward the west. Conditions in the western Caribbean Sea are nearly perfect for rapid intensification, deep warm water within the start of the Gulf loop current, favorable light winds aloft, and a decent outflow channel on the SW side of the FL high to help expel and vent the system. The 06Z runs of the GFDL and HWRF are both at the extreme end of the intensity guidance showing a category 5 hurricane moving through the Gulf with very deep pressures of 892mb and 904mb, while SHIPS only shows 81kts at 96 and 120 hours. The NHC forecast maintains a major hurricane event into the central Gulf of Mexico with 120mph sustained winds nearly splitting the intensity guidance. Once the inner core of Gustav reforms there appears to be little to prevent intensification and Gustav could easily be stronger than NHC is forecasting in the Gulf and this is noted in their discussions.


Actions:


Residents along the US Gulf coast should be reviewing their hurricane plans and be prepared to activate those plans this weekend.