Isaac now forecast to become a hurricane.
Tropical Storm Isaac continues to improve in structure today, continuing a steady trend that began overnight. Initially, Isaac was basically purely tropical, having been forming out of a tropical wave, but over the past day or two, as former Invest 96L interacted with a colder upper level low, he had become largely subtropical, and perhaps in post-season reanalysis his initial couple of days will be reclassified as such during this period.
Today Isaac has been offering hints at building an eye, and slowly deepening convection has been progressively wrapping about this center. We may indeed have a Hurricane Isaac before long.
Isaac
Image Credit: NRL
From NHC:
"NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092006
500 PM EDT FRI SEP 29 2006
CONVECTION HAS BEEN INTENSIFYING AND ATTEMPTING TO FORM A RING
AROUND THE CENTER OF ISAAC. IN ADDITION THE OUTFLOW HAS BEEN
EXPANDING AND BECOMING MORE SYMMETRIC. THESE ARE ALL SIGNS OF AN
INTENSIFYING SYSTEM. DVORAK T-NUMBERS HAVE INCREASED MARKEDLY...
AND SINCE AN EARLIER QUIKSCAT PASS SUPPORTED WINDS OF 40-45 KT
TWELVE HOURS AGO... THE INITIAL INTENSITY IS RAISED TO 50 KT. ISAAC
IS LEAVING THE COOLER WATERS PREVIOUSLY UPWELLED BY GORDON AND
HELENE AND MOVING INTO WARMER SSTS. IN ADDITION... THE DRY AIR IN
THE MIDDLE TO UPPER LEVELS NEAR THE SYSTEM'S CORE HAS BEEN REDUCED
AND THERE IS LITTLE SHEAR APPARENT ON SATELLITE IMAGES. THESE
FACTORS SUPPORT INTENSIFICATION FOR THE NEXT 36 HOURS OR SO. THUS
THE INTENSITY FORECAST IS RAISED FROM THE PREVIOUS ONE AND SHOWS
ISAAC BECOMING A HURRICANE. THE FORECAST IS HIGHER THAN THE
PREVIOUS ONE AND IN BEST AGREEMENT WITH A BLEND OF THE SHIPS/FSSE."
Today Isaac has been offering hints at building an eye, and slowly deepening convection has been progressively wrapping about this center. We may indeed have a Hurricane Isaac before long.
Isaac
Image Credit: NRL
From NHC:
"NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092006
500 PM EDT FRI SEP 29 2006
CONVECTION HAS BEEN INTENSIFYING AND ATTEMPTING TO FORM A RING
AROUND THE CENTER OF ISAAC. IN ADDITION THE OUTFLOW HAS BEEN
EXPANDING AND BECOMING MORE SYMMETRIC. THESE ARE ALL SIGNS OF AN
INTENSIFYING SYSTEM. DVORAK T-NUMBERS HAVE INCREASED MARKEDLY...
AND SINCE AN EARLIER QUIKSCAT PASS SUPPORTED WINDS OF 40-45 KT
TWELVE HOURS AGO... THE INITIAL INTENSITY IS RAISED TO 50 KT. ISAAC
IS LEAVING THE COOLER WATERS PREVIOUSLY UPWELLED BY GORDON AND
HELENE AND MOVING INTO WARMER SSTS. IN ADDITION... THE DRY AIR IN
THE MIDDLE TO UPPER LEVELS NEAR THE SYSTEM'S CORE HAS BEEN REDUCED
AND THERE IS LITTLE SHEAR APPARENT ON SATELLITE IMAGES. THESE
FACTORS SUPPORT INTENSIFICATION FOR THE NEXT 36 HOURS OR SO. THUS
THE INTENSITY FORECAST IS RAISED FROM THE PREVIOUS ONE AND SHOWS
ISAAC BECOMING A HURRICANE. THE FORECAST IS HIGHER THAN THE
PREVIOUS ONE AND IN BEST AGREEMENT WITH A BLEND OF THE SHIPS/FSSE."