WTPZ41 KNHC 030847 RRA

TCDEP1



HURRICANE SERGIO DISCUSSION NUMBER  16

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP212018

200 AM PDT WED OCT 03 2018



THERE HAS BEEN LITTLE CHANGE TO THE OVERALL ORGANIZATION OF THE

HURRICANE OVERNIGHT.  RECENT MICROWAVE DATA CONTINUE TO SHOW

THAT THE EYEWALL IS OPEN TO THE NORTHWEST AND THAT THERE IS

SOME NORTHEAST TO SOUTHWEST DISPLACEMENT OF THE LOW- AND MID-LEVEL

CENTERS DUE TO NORTHEASTERLY SHEAR.  A BLEND OF THE VARIOUS

OBJECTIVE AND SUBJECTIVE SATELLITE INTENSITY ESTIMATES YIELDS

AN INITIAL INTENSITY OF 100 KT.  THE GLOBAL MODELS SUGGEST THAT

THE SHEAR CURRENTLY AFFECTING SERGIO WILL DECREASE OVER THE NEXT 24

TO 36 HOURS, WHICH SHOULD ALLOW FOR STRENGTHENING.  THE NHC

INTENSITY FORECAST CALLS FOR SERGIO TO REACH PEAK INTENSITY IN

ABOUT 36 HOURS, AND IT IS NEAR THE UPPER-END OF THE INTENSITY

GUIDANCE.  AFTER THAT TIME, SLIGHTLY COOLER WATERS AND THE

ENTRAINMENT OF DRIER MID-LEVEL AIR ARE FORECAST TO CAUSE GRADUAL

WEAKENING, BUT SERGIO IS EXPECTED TO REMAIN A HURRICANE THROUGH THE

ENTIRE FORECAST PERIOD.



SERGIO IS MOVING WEST-NORTHWESTWARD OR 300 DEGREES AT 10 KT.  THE

WESTERN PORTION OF A MID-LEVEL RIDGE TO THE NORTH OF SERGIO IS

EXPECTED TO WEAKEN DURING THE NEXT DAY OR SO, WHICH SHOULD CAUSE THE

HURRICANE TO MOVE NORTHWESTWARD AT A SLIGHTLY SLOWER FORWARD SPEED.

BY THE WEEKEND, ANOTHER RIDGE IS PREDICTED TO BUILD TO THE

NORTHWEST OF SERGIO, AND THIS SHOULD FORCE THE HURRICANE TO TURN

WESTWARD.  THE TRACK GUIDANCE IS IN GOOD AGREEMENT THROUGH 48

HOURS, BUT THERE IS INCREASING CROSS-TRACK SPREAD THEREAFTER.  THE

UPDATED NHC FORECAST IS NEAR THE MIDDLE OF THE GUIDANCE ENVELOPE FOR