TROPICAL STORM DEAN DISCUSSION NUMBER 5 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042007 1100 AM EDT TUE AUG 14 2007

SATELLITE IMAGES...MICROWAVE DATA AND QUIKSCAT MEASUREMENTS INDICATE
THAT THE DEPRESSION HAS REACHED TROPICAL STORM STATUS AND ALSO THAT
THE CENTER IS LOCATED FARTHER TO THE SOUTH AND WEST THAN PREVIOUSLY
INDICATED. DEAN HAS DEVELOPED A SMALL CENTRAL DENSE OVERCAST OVER
THE CENTER BUT MOST OF THE CONVECTION IS STILL LOCATED TO THE WEST
AND SOUTH OF THE CENTER. THE OUTFLOW IS CONFINED TO THE WEST AND
SOUTHWEST SINCE THE CYCLONE IS STILL EMBEDDED WITHIN EASTERLY
SHEAR. THE SHEAR IS FORECAST TO DECREASE AND MOST OF THE INTENSITY
GUIDANCE GRADUALLY STRENGTHENS DEAN. IN FACT...DYNAMICAL GUIDANCE
SUGGESTS THAT DEAN COULD BE NEAR THE LESSER ANTILLES AS A HURRICANE
WITH 100 TO 110 KNOTS IN FIVE DAYS.

DEAN APPEARS TO BE MOVING WESTWARD OR 265 DEGREES AT 20 KNOTS AROUND
THE PERIPHERY OF A STRONG SUBTROPICAL RIDGE WHICH IS EXPANDING
WESTWARD. IN THE SHORT TERM...2 TO 3 DAYS...DEAN SHOULD CONTINUE TO
MOVE ON A GENERAL WESTWARD TRACK WITH A GRADUAL DECREASE IN FORWARD
SPEED. THEREAFTER...THE FORECAST BECOMES HIGHLY UNCERTAIN SINCE
SOME RELIABLE MODELS MAINTAIN A STRONG RIDGE TO THE NORTH AND KEEP
THE CYCLONE MOVING WESTWARD ACROSS THE CARIBBEAN AND OTHERS SHOW A
WEAKER RIDGE RESULTING IN A GRADUAL TURN TO THE WEST-NORTHWEST. THE
OFFICIAL FORECAST FOLLOWS THE CONSENSUS AND IS A LITTLE BIT TO THE
SOUTH OF THE PREVIOUS ONE...DUE TO THE REPOSITIONING OF THE
CENTER...AND NOT BECAUSE WE HAVE CHANGED THE FORECAST REASONING.

FORECAST POSITIONS AND MAX WINDS

INITIAL 14/1500Z 11.7N 39.4W 35 KT
12HR VT 15/0000Z 11.8N 42.0W 40 KT
24HR VT 15/1200Z 11.8N 45.6W 45 KT
36HR VT 16/0000Z 11.8N 48.5W 50 KT
48HR VT 16/1200Z 12.0N 51.5W 60 KT
72HR VT 17/1200Z 13.5N 56.5W 70 KT
96HR VT 18/1200Z 15.5N 61.0W 80 KT
120HR VT 19/1200Z 17.5N 65.0W 95 KT