WTPA41 PHFO 061506 RRA

TCDCP1





POST-TROPICAL CYCLONE WALAKA DISCUSSION NUMBER  28

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP012018

500 AM HST SAT OCT 06 2018



WALAKA'S LOW-LEVEL CIRCULATION CENTER (LLCC) REMAINS COMPLETELY

DEVOID OF DEEP CONVECTION EARLY THIS MORNING.  THE LAST FEW

THUNDERSTORMS ASSOCIATED WITH THE SYSTEM ARE SLIGHTLY MORE THAN

90 N MI SOUTHEAST OF THE EXPOSED LLCC. ASCAT PASSES OVER WALAKA AT

0735Z AND 0838Z SHOWED THE SYSTEM WAS STRONGER THAN EXPECTED, WITH

SURFACE WIND SPEEDS UP TO 45 KT. IT WAS ALSO APPARENT THE CENTER OF

THE SYSTEM WAS BECOMING ELONGATED INSTEAD OF CIRCULAR. IN ADDITION,

THE WIND FIELD WAS HIGHLY ASYMMETRIC, WITH THE STRONGEST WINDS IN A

BROAD AREA COVERING THE SOUTHEASTERN SEMICIRCLE, WHILE THE WINDS

WERE MUCH WEAKER OVER MOST OF THE NORTHWESTERN SEMICIRCLE. BASED ON

THIS EVIDENCE, WALAKA HAS ALREADY TRANSITIONED TO AN EXTRATROPICAL

GALE LOW THIS MORNING. THE INITIAL INTENSITY FOR THIS ADVISORY IS

45 KT DUE TO THE ASCAT DATA FROM LAST EVENING.



THE INITIAL MOTION FOR THIS ADVISORY IS 035/23 KT. WALAKA IS BEING

STEERED BY THE DEEP SOUTHWESTERLY FLOW ASSOCIATED WITH AN ADVANCING

UPPER-LEVEL TROUGH. AS A RESULT, IT WILL LIKELY CONTINUE TO MOVE

TOWARD THE NORTHEAST OR NORTH-NORTHEAST AT AN INCREASING FORWARD

SPEED THIS WEEKEND. THE LATEST TRACK FORECAST HAS BEEN ADJUSTED

SLIGHTLY TO THE LEFT COMPARED WITH THE PREVIOUS ADVISORY PACKAGE.

THIS FOLLOWS A BLEND OF THE TRACK GUIDANCE BASED ON THE LATEST

OPERATIONAL RUNS AND THE ENSEMBLE MEANS FROM THE GFS AND ECMWF

MODELS.



THE BAROCLINIC PROCESSES DRIVING WALAKA'S NEW LIFE AS AN

EXTRATROPICAL SYSTEM WILL LIKELY MAINTAIN AN AREA OF GALE FORCE