Hurricane Gustav rapidly intensified into a hurricane on 26 August 2008 (less than 24 hours after the first advisory was issued). As noted by the National Hurricane Center’s Gustav discussion number 6:
HURRICANE GUSTAV DISCUSSION NUMBERÂ Â 6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FLÂ Â AL072008
1100 AM EDT TUE AUG 26 2008
AN AIR FORCE RECONNAISSANCE MISSION EARLY THIS MORNING FOUND PEAK FLIGHT-LEVEL WINDS OF 91 KT…AND AN SFMR SURFACE WIND OF 78 KT. THESE MEASUREMENTS SUPPORT AN INITIAL INTENSITY OF 80 KT.Â A DROPSONDE RELEASED IN THE EYE OF GUSTAV DURING THE LAST AIRCRAFT PASS THROUGH THE CENTER JUST BEFORE 1200 UTC…FOUND A SURFACE PRESSURE OF 982 MB…BUT WITH 12 KT OF WIND AT THE SURFACE…SO THE MINIMUM PRESSURE HAS BEEN ESTIMATED SLIGHTLY LOWER.Â THE AIRCRAFT AND EARLIER MICROWAVE SATELLITE IMAGERY INDICATE THE PRESENCE OF A VERY SMALL EYE…HOWEVER THE EYE HAS NOT YET BECOME APPARENT IN CONVENTIONAL SATELLITE IMAGERY.
A comparison ofÂ imagery from the CIMSS Tropical Cyclones site (above) shows the shield of central dense overcast (cold cloud tops) on the GOES-12 IR image, with evidence of an eye structure showing up on the SSM/IS microwave image. 1-km resolution GOES-12 visible imagery (below) also did not display an eye with Hurricane Gustav during the morning hours.