The National Hurricane Center’s 5:00 AM update:
AN AIR FORCE RECONNAISSANCE PLANE HAS FOUND A SURPRISE THIS MORNING. GUSTAV HAS EITHER REFORMED TO THE SOUTH OR BEEN MOVING MORE TO THE SOUTH-SOUTHWEST OVERNIGHT. IN ADDITION…THE PRESSURE IS DOWN 10 MB DURING THE LAST SIX HOURS. THE PLANE HAS NOT YET SAMPLED THE ENTIRE STORM…BUT IT IS ASSUMED THE WINDS HAVE COME UP SLIGHTLY WITH THE SIGNIFICANT PRESSURE FALL AND THE INITIAL INTENSITY IS INCREASED TO 45 KT. MID-LEVEL DRY AIR…SOME NORTHEASTERLY SHEAR…AND INTERACTION WITH JAMAICA MAY LIMIT THE INTENSIFICATION OF THIS SYSTEM DURING THE NEXT DAY OR SO. THUS THE OFFICIAL INTENSITY FORECAST IS ONLY SLIGHTLY RAISED FROM EARLIER. THEREAFTER…THE GLOBAL MODELS ARE FORECASTING AN UPPER ANTICYCLONE TO BE NEAR THE CENTER OF GUSTAV…WHICH WOULD BE QUITE FAVORABLE FOR STRENGTHENING. IT IS EXPECTED THAT GUSTAV WILL BE A POWERFUL HURRICANE AS IT MOVES INTO THE SOUTHERN GULF OF MEXICO ON SUNDAY. SOUTHWESTERLY VERTICAL WIND SHEAR COULD INCREASE LATE IN THE PERIOD WHEN THE SYSTEM IS FORECAST TO BE IN THE NORTHERN GULF BUT THERE IS CONSIDERABLY UNCERTAINTY AT THAT TIME.
That’s a very large overnight fall in pressure but I suspect that we’ll see more surprising drops in pressure once this storm hits the Gulf of Mexico. The NHC followed up with a special advisory just a few minutes ago that confirms strengthening:
AN AIR FORCE RECONNAISSANCE PLANE HAS FOUND MAXIMUM 700 MB FLIGHT LEVEL WINDS OF 67 KT…CORRESPONDING TO ABOUT 60 KT AT THE SURFACE. THIS SPECIAL ADVISORY IS TO UPDATE THE INTENSITY FORECAST TO REFLECT THE CURRENT AND FORECAST INTENSITY. THERE HAS NOT BEEN ANY SIGNIFICANT CHANGE TO THE TRACK FORECAST. THE STRENGTHENING OF GUSTAV HAS PROMPTED THE GOVERNMENT OF JAMAICA TO ISSUE A HURRICANE WARNING FOR JAMAICA.
The NHC’s shift of the forecasted track to west, which many models have shown as well, is cause for concern here in Texas but it has to be stressed that anyone on the Gulf of Mexico could be impacted by Gustav. We should have a much better feel for it’s eventual landfall point by Sunday.
