The National Hurricane Center’s 5 AM update is, as expected, was full of bad news:

GUSTAV HAS BEEN RAPIDLY INTENSIFYING DURING THE OVERNIGHT HOURS. SATELLITE IMAGES INDICATE THAT AN EYE IS BECOMING VISIBLE AND DEEP CONVECTION SURROUNDING THE EYE IS NOW VERY INTENSE. THE CENTRAL PRESSURE IS DOWN TO 965 MB…A DROP OF ABOUT 24 MB IN 24 HOURS. THE MAXIMUM FLIGHT LEVEL WINDS REPORTED BY THE AIR FORCE CREW WERE 100 KT AROUND 6Z… CORRESPONDING TO ABOUT 90 KT AT THE SURFACE. HOWEVER THE SATELLITE PRESENTATION HAS CONTINUED TO IMPROVE…THUS THE INITIAL INTENSITY IS INCREASED CONSERVATIVELY TO 95 KT. OBJECTIVE DVORAK T-NUMBERS ARE MUCH HIGHER AND THE NEXT AIRCRAFT PASS THROUGH GUSTAV COULD FIND A MAJOR HURRICANE.

FURTHER INTENSIFICATION IS EXPECTED FOR THE NEXT DAY OR SO WHILE THE SYSTEM TRAVERSES THE EXTREMELY WARM AND DEEP WATERS OF THE NORTHWESTERN CARIBBEAN SEA AND SOUTHERN GULF OF MEXICO. HOWEVER…BY 48 HOURS…ALMOST ALL OF THE GLOBAL MODELS SHOW AN INCREASE IN VERTICAL WIND SHEAR NEAR GUSTAV. IN ADDITION…SINCE THE LOOP CURRENT IS SOUTH OF ITS TYPICAL LOCATION…THE HURRICANE WILL BE MOVING OVER WATERS THAT ARE NOT NEARLY AS CONDUCIVE FOR
STRENGTHENING AS THEY COULD BE. THESE TWO FACTORS WILL HOPEFULLY WEAKEN THE STORM PRIOR TO U.S. LANDFALL. HOWEVER…GUSTAV IS EXPECTED TO BE A LARGE AND DANGEROUS HURRICANE AND THE NHC FORECAST CONTINUES TO SHOW GUSTAV AS A MAJOR HURRICANE AT LANDFALL.

THE INITIAL MOTION ESTIMATE IS 310/10. A MID-LEVEL RIDGE FROM THE WESTERN ATLANTIC TO NORTHERN FLORIDA IS EXPECTED TO CONTINUE MOVING THE HURRICANE TO THE NORTHWEST FOR THE NEXT COUPLE OF DAYS. THEREAFTER…A RIDGE OVER THE OHIO VALLEY SHOULD CAUSE A GRADUAL LEFTWARD BEND IN THE TRACK AS GUSTAV APPROACHES THE NORTHERN GULF COAST. MOST OF THE GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO EXCEPT FOR THE UKMET/HWRF…WHICH TURN THE SYSTEM JUST OFFSHORE. THESE TWO MODELS ARE SLOWER AND TO THE LEFT OF MOST OF THE TRACK GUIDANCE…WHICH ALLOWS A RIDGE TO FORM OVER TEXAS TO TURN THE STORM. THE OFFICIAL FORECAST WILL STAY WITH THE MAJORITY OF THE GUIDANCE AND IS BASICALLY AN UPDATE TO THE PREVIOUS PACKAGE. GUSTAV WILL LIKELY SLOW DOWN SIGNIFICANTLY IN THE LONGER-TERM…WHICH COULD CAUSE A CONSIDERABLE FLOODING THREAT OVER LOUISIANA OR TEXAS.

But just an hour later, in a 6 AM special update, the news got worse:

DATA FROM AN AIR FORCE RECONNAISSANCE AIRCRAFT INDICATE THAT GUSTAV CONTINUES TO RAPIDLY STRENGTHEN AND NOW HAS MAXIMUM WINDS NEAR 115 MPH…185 KM/HR WITH HIGHER GUSTS. THIS MAKES GUSTAV A DANGEROUS CATEGORY THREE HURRICANE ON THE SAFFIR-SIMPSON HURRICANE SCALE…THE SECOND MAJOR HURRICANE OF THE 2008 ATLANTIC HURRICANE SEASON.

If you live on the upper Texas coast or in Louisiana you absolutely need to start preparing today if you haven’t started already. Gustav is almost certainly going to cause significant damage and loss of life wherever it strikes.

There’s still a great deal of uncertainty surrounding the storm’s track and I expect that to be the case for the next 36-48 hours:

GUSTAV IS MOVING AT ABOUT 295/7 BUT IS IN THE PROCESS OF TURNING TO THE RIGHT IN RESPONSE TO THE RIDGE TO ITS NORTH…AND IS HEADED FOR A WEAKNESS IN THE RIDGE THAT IS FORECAST BY ALL MODELS TO DEVELOP OVER THE EASTERN GULF OF MEXICO DURING THE NEXT COUPLE OF DAYS. THE GUIDANCE IS IN VERY GOOD AGREEMENT ON A PATH OVER THE WESTERN PORTIONS OF CUBA IN ROUGHLY 36 HOURS…FOLLOWED BY A TRACK INTO THE SOUTH-CENTRAL GULF OF MEXICO. THEREAFTER…THE MODELS DIVERGE TREMENDOUSLY OVER THE NORTHERN GULF DUE TO DIFFERENCES IN HOW THEY HANDLE THE HIGH MOVING EASTWARD ACROSS THE GREAT LAKES REGION. THE MODELS THAT SHOW A SLOWER AND MORE WESTWARD MOTION ACROSS THE NORTHERN GULF SHOW A LITTLE MORE RIDGING EXTENDING SOUTHWESTWARD FROM THE GREAT LAKES HIGH…WHILE THOSE THAT ARE FASTER AND STRAIGHT NORTHWESTWARD TOWARD THE NORTH-CENTRAL GULF COAST SHOW LESS OF THAT RIDGING. THE NEW OFFICIAL TRACK FORECAST IS ADJUSTED ONLY SLIGHTLY RIGHT OF THE PREVIOUS ADVISORY AND THE CONSENSUS…GIVING RESPECT TO THE NWS MODELS GFS…GFDL…AND HWRF…WHICH ALSO SEEM TO DEPICT A SLIGHTLY DEEPER SYSTEM THAT WE EXPECT GUSTAV TO BE. NEEDLESS TO SAY…DUE TO THE MODEL SPREAD THE TRACK FORECAST IS RATHER UNCERTAIN…AND FINAL LANDFALL REMAINS POSSIBLE THROUGHOUT THE NORTHERN GULF COAST.

The NHC forecast may bounce left and right a few miles for the next few days but residents from Texas to Florida should remain vigilant until the track is dialed in.