| HOME | ARCHIVES | FORECASTS | IMAGERY | ABOUT NHC | RECONNAISSANCE |

---

Hurricane ISABEL (Text)

ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
HURRICANE ISABEL DISCUSSION NUMBER  38
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT MON SEP 15 2003
 
SATELLITE IMAGERY INDICATES THAT THE INNER CORE STRUCTURE CONTINUES
TO BREAK DOWN...WITH A LESS WELL-DEFINED EYE IN VISIBLE IMAGERY. 
EYEWALL CONVECTION HAS BECOME ASYMMETRIC AND FRAGMENTED...AND THE
OVERALL CONVECTIVE STRUCTURE IS NOW MORE BANDED THAN IT WAS OVER
THE PAST COUPLE OF DAYS.  THE LATEST DVORAK SATELLITE INTENSITY
ESTIMATES ARE 115 KT.  THE ADVISORY INTENSITY IS LOWERED TO 120 KT
AND ANOTHER RECONNAISSANCE AIRCRAFT WILL BE IN THE HURRICANE AT
18Z.

THE INITIAL MOTION IS 300/7...SLOWER THAN BEFORE.  WITH THE
MID-LEVEL SHORT WAVE OFF THE CAROLINAS MOVING OUT TO THE
NORTHEAST...THE STEERING CURRENTS SURROUNDING ISABEL ARE BEGINNING
TO WEAKEN AS SOME RIDGING TEMPORARILY BUILDS IN NORTHWEST...AHEAD
OF...THE HURRICANE.  THIS SHOULD RESULT IN A SLOW MOTION TO THE
NORTHWEST OVER THE NEXT DAY OR TWO.  BY 48 HOURS OR SO...AN
APPROACHING TROUGH FROM THE WEST WILL HELP ACCELERATE ISABEL
NORTH-NORTHWESTWARD AROUND THE WEST SIDE OF THE DEEP-LAYER RIDGE
ANCHORED NEAR 35N AND 60 W.  MODEL GUIDANCE IS IN EXCELLENT
AGREEMENT ON THIS TRACK ALTHOUGH THE GFS IS CONSIDERABLY SLOWER
THAN THE OTHER MODELS.  VERY LITTLE CHANGE HAS BEEN MADE TO THE
OFFICIAL FORECAST TRACK...WHICH IS VERY CLOSE TO THE GFDL...
UKMET...NOGAPS...GFS MODEL CONSENSUS.  

ALTHOUGH THERE HAS BEEN SOME RESTRICTION OF THE OUTFLOW IN THE
SOUTHWEST QUADRANT...THE CURRENT WEAKENING MAY BE MORE A RESULT OF
LESS FAVORABLE ENVIRONMENTAL THERMODYNAMICS.  THERE ARE WESTERLIES
TO THE NORTH OF ISABEL...BUT THE SHEAR IS EXPECTED TO BE LIGHT FOR
THE NEXT 36 HOURS OR SO.    THERE WILL BE PLENTY OF WARM WATER
UNDER THE HURRICANE UNTIL COOLER SHELF WATERS ARE ENCOUNTERED RIGHT
ALONG THE COASTLINE.  ONE KEY TO THE ULTIMATE LANDFALL INTENSITY
WILL BE THE EVOLUTION OF AN UPPER-LEVEL TROUGH THAT COULD ENHANCE
THE OUTFLOW AND REDUCE THE SHEAR PRIOR TO LANDFALL IF IT DIGS AS
SHARPLY AS FORECAST BY THE GFS.  WITH THIS IN MIND...ISABEL COULD
STILL BE A MAJOR HURRICANE AT LANDFALL.

 FORECASTER FRANKLIN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      15/1500Z 25.2N  69.4W   120 KT
 12HR VT     16/0000Z 25.8N  70.3W   115 KT
 24HR VT     16/1200Z 27.0N  71.2W   115 KT
 36HR VT     17/0000Z 28.2N  72.0W   115 KT
 48HR VT     17/1200Z 30.0N  73.0W   115 KT
 72HR VT     18/1200Z 34.5N  75.5W   110 KT
 96HR VT     19/1200Z 40.0N  78.0W    60 KT...INLAND
120HR VT     20/1200Z 49.5N  80.0W    30 KT...EXTRATROPICAL
 
 
NNNN