WTNT42 KNHC 231435 RRA

TCDAT2



TROPICAL STORM GASTON DISCUSSION NUMBER   4

NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072016

1100 AM AST TUE AUG 23 2016



GASTON CONTINUES TO INTENSIFY.  THE CYCLONE'S CLOUD PATTERN HAS BEEN

GRADUALLY TRANSITIONING FROM A CURVED-BAND PATTERN TO A CENTRAL

DENSE OVERCAST (CDO).  WITHIN THE FORMATIVE CDO, A RAGGED EYE-TYPE

FEATURE HAS OCCASIONALLY BEEN EVIDENT DURING THE LAST FEW HOURS.  A

SATELLITE CLASSIFICATION OF T3.5 IS USED TO INCREASE IN THE INITIAL

INTENSITY ESTIMATE TO 55 KT, IN AGREEMENT WITH THE LATEST UW-CIMSS

ADT VALUES.



ONLY LIGHT VERTICAL WIND SHEAR IS FORECAST TO AFFECT GASTON DURING

THE NEXT 24 TO 36 HOURS WHILE THE CYCLONE MOVES OVER MARGINALLY

WARM WATERS AND THROUGH A GENERALLY MOIST ENVIRONMENT.  THESE

FACTORS SUGGEST THAT FURTHER INTENSIFICATION IS LIKELY DURING THIS

PERIOD OF TIME.  BY 48 HOURS, GASTON SHOULD ENCOUNTER INCREASING

SOUTHWESTERLY TO WESTERLY FLOW AT UPPER-LEVELS ASSOCIATED WITH A

POTENT TROUGH OVER THE EAST-CENTRAL ATLANTIC.  IN THE VERY LEAST,

THE FORECAST SHEAR AND A DRIER ATMOSPHERE ASSOCIATED WITH THIS

FEATURE SHOULD RESULT IN AN ARRESTED DEVELOPMENT PHASE, IF NOT

WEAKENING.  LATE IN THE FORECAST PERIOD, GLOBAL MODELS INDICATE A

REDUCTION OF THE SHEAR WHILE GASTON IS OVER WARMER WATERS OF 29 DEG

C, WHICH COULD ALLOW FOR SOME RE-STRENGTHENING.  THROUGH 36 HOURS,

THE NHC INTENSITY FORECAST IS A BIT ABOVE THE MULTI-MODEL CONSENSUS

AND CLOSEST TO THE FSU SUPERENSEMBLE OUTPUT AND THE LGEM. AFTER THAT

TIME, THE FORECAST TRENDS TOWARD THE MULTI-MODEL CONSENSUS.



THE INITIAL MOTION ESTIMATE IS 285/18.  GASTON IS BEING STEERED

QUICKLY TOWARD THE WEST-NORTHWEST AROUND THE WESTERN EXTENSION OF=