WTPZ41 KNHC 020852 RRA

TCDEP1



HURRICANE SERGIO DISCUSSION NUMBER  12

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP212018

300 AM MDT TUE OCT 02 2018



GEOSTATIONARY SATELLITE IMAGERY INDICATES THAT SERGIO CONTINUES TO

STRENGTHEN.   THE CENTER IS LOCATED WITHIN A FAIRLY SYMMETRIC CDO

WITH CLOUD TOPS OF -70 TO -80 DEGREES C.  EARLIER MICROWAVE DATA

SHOWED A WELL-DEFINED EYE AND INNER CORE, BUT A MORE RECENT AMSU

OVERPASS SUGGESTS THAT THERE HAS BEEN SOME SLIGHT EROSION OF THE

EASTERN PORTION OF THE EYE, POSSIBLY DUE TO SOME INTRUSION OF DRY

MID-LEVEL AIR.  DVORAK INTENSITY ESTIMATES RANGED FROM 75 TO 90 KT,

AND THE INITIAL INTENSITY HAS BEEN INCREASED TO A POSSIBILITY

CONSERVATIVE 75 KT FOR THIS ADVISORY.



THE INTENSITY FORECAST REMAINS SOMEWHAT UNCERTAIN.  ALTHOUGH

SERGIO HAS DEVELOPED AN INNER CORE AND STRENGTHENED DURING THE PAST

12 HOUR OR SO, THE DYNAMICAL MODELS SUGGEST NORTHEASTERLY SHEAR

WILL INCREASE OVER THE HURRICANE TODAY.  THIS IS EXPECTED TO TEMPER

THE INTENSIFICATION SOMEWHAT OVER THE NEXT 12-24 HOURS, HOWEVER,

MOST OF THE GUIDANCE SHOWS AT LEAST GRADUAL STRENGTHENING DURING

THE NEXT DAY OR SO.  THE NHC INTENSITY FORECAST CALLS FOR A GRADUAL

INCREASE IN WIND SPEED OVER THE NEXT 36-48 HOURS, AND IS CLOSE TO

THE IVCN MODEL CONSENSUS.  AFTER 72 H, COOLER WATERS AND THE

ENTRAINMENT OF DRIER AIR IS EXPECTED TO CAUSE GRADUAL WEAKENING.



SERGIO IS MOVING SLIGHTLY SOUTH OF DUE WEST OR 265/12 KT.  THE

HURRICANE IS CURRENTLY LOCATED TO THE SOUTH OF A MID-LEVEL RIDGE,

AND SERGIO SHOULD CONTINUE WESTWARD TODAY.  THE GLOBAL MODELS SHOW

THE WESTERN PORTION OF THE RIDGE WEAKENING OVER THE NEXT SEVERAL

DAYS, WHICH SHOULD CAUSE SERGIO TO TURN WEST-NORTHWESTWARD, THEN