000 WTNT43 KNHC 080836 TCDAT3 TROPICAL STORM CHANTAL DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL032013 500 AM EDT MON JUL 08 2013 CHANTAL HAS CHANGED LITTLE IN ORGANIZATION ON SATELLITE IMAGERY OVER THE PAST FEW HOURS. CONVECTIVE BANDING FEATURES ARE NOT YET WELL DEFINED...AND THE CLOUD PATTERN IS CURRENTLY A LITTLE RAGGED-LOOKING IN APPEARANCE. DVORAK T-NUMBERS FROM TAFB AND SAB REMAIN 2.5...SO THE INTENSITY ESTIMATE IS HELD AT 35 KT FOR THIS ADVISORY. THE VERTICAL SHEAR OVER THE AREA IS NOT STRONG AT THIS TIME...BUT THE SHIPS MODEL INDICATES THAT WESTERLY SHEAR WILL INCREASE IN 1-2 DAYS. ALSO...CLIMATOLOGY SUGGESTS THAT TROPICAL CYCLONES THAT MOVE RAPIDLY WESTWARD OR WEST-NORTHWESTWARD IN THE DEEP TROPICS HAVE DIFFICULTY STRENGTHENING. THE OFFICIAL INTENSITY FORECAST IS THE SAME AS THE PREVIOUS ONE THROUGH THE FORECAST PERIOD...AND CLOSE TO THE MODEL CONSENSUS THROUGH 48 HOURS. BEYOND 2 DAYS...IT IS EXPECTED THAT CHANTAL WILL HAVE INTERACTED WITH THE LAND MASSES OF HISPANIOLA AND EASTERN CUBA...WHICH SHOULD CAUSE WEAKENING IN THE 3-4 DAY TIME FRAME. NEAR THE END OF THE FORECAST PERIOD...THE GLOBAL MODELS SHOW UPPER-TROPOSPHERIC WESTERLIES OVER THE FORECAST TRACK AND THIS SHOULD LEAD TO FURTHER WEAKENING. CONFIDENCE IN THE 3-5 DAY INTENSITY FORECAST...HOWEVER...IS NOT HIGH. LATEST SATELLITE FIXES INDICATE THAT A RAPID WESTWARD MOTION... 280/23...IS CONTINUING. THERE ARE NO BIG CHANGES TO THE TRACK FORECAST REASONING FROM THE PREVIOUS ADVISORY. CHANTAL IS EXPECTED TO MOVE QUICKLY TOWARD THE WEST-NORTHWEST TO THE SOUTH OF A PRONOUNCED MID-LEVEL RIDGE FOR THE NEXT DAY OR SO. A STRONG HIGH PRESSURE CELL OVER THE SOUTHWEST NORTH ATLANTIC SHOULD RESULT IN A CONTINUED WEST-NORTHWESTWARD MOTION IN 2-3 DAYS. THEREAFTER...A WEAKNESS IN THE RIDGE OVER THE EASTERN GULF OF MEXICO AND THE FLORIDA PENINSULA SHOULD LEAD TO A TURN TOWARD THE NORTHWEST AND NORTH-NORTHWEST. THE OFFICIAL TRACK FORECAST IS VERY SIMILAR TO THE PREVIOUS ONE...AND TO THE LATEST MODEL CONSENSUS...THROUGH 48 HOURS. AT 3-5 DAYS...THE NHC TRACK IS SHIFTED JUST SLIGHTLY EAST OF THE PREVIOUS ONE. THE GFS...ONE OF THE FEW DYNAMICAL MODELS TO MAINTAIN A COHERENT VORTEX THROUGH DAY 5...IS FARTHER TO THE EAST OF THE OFFICIAL FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 08/0900Z 10.4N 49.5W 35 KT 40 MPH 12H 08/1800Z 11.4N 53.0W 40 KT 45 MPH 24H 09/0600Z 12.9N 57.6W 45 KT 50 MPH 36H 09/1800Z 14.6N 62.2W 50 KT 60 MPH 48H 10/0600Z 16.2N 66.6W 55 KT 65 MPH 72H 11/0600Z 19.0N 73.5W 45 KT 50 MPH 96H 12/0600Z 22.5N 76.5W 35 KT 40 MPH 120H 13/0600Z 25.5N 77.5W 30 KT 35 MPH $$ FORECASTER PASCH