WTPA41 PHFO 300908 RRA

TCDCP1



TROPICAL STORM WALAKA DISCUSSION NUMBER   3

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP012018

1100 PM HST SAT SEP 29 2018



THE SATELLITE PRESENTATION OF WALAKA HAS IMPROVED THIS EVENING,

WITH AN INCREASE IN DEEP CONVECTION AROUND THE LOW LEVEL

CIRCULATION CENTER. SEVERAL MICROWAVE PASSES WERE HELPFUL IN

DETERMINING THE CENTER LOCATION, BUT ALSO INDICATED THAT THE

TROPICAL STORM LACKS GOOD ORGANIZATION AT THE MOMENT. THE LATEST

SATELLITE INTENSITY ESTIMATES FROM PHFO, SAB AND JTWC ALL CAME IN AT

2.5 (35 KNOTS) WITH THE ADT VALUE FROM UW-CIMSS APPEARING

UNREALISTICALLY HIGH AT 3.6 (57 KNOTS). AS A RESULT, THE INITIAL

INTENSITY FOR THIS ADVISORY WILL BE HELD AT 35 KNOTS. THE INITIAL

MOTION BASED ON INTERPOLATING BETWEEN MICROWAVE PASSES ALONG WITH

GEOSTATIONARY SATELLITE ANIMATIONS WILL BE SET AT 270/14 KNOTS.



WALAKA IS EXPECTED TO TRACK NEARLY DUE WEST ALONG THE SOUTH SIDE OF

A SUBTROPICAL RIDGE THROUGH SUNDAY NIGHT, WITH A GRADUAL DECREASE

IN FORWARD SPEED. A DEEP NORTH PACIFIC UPPER TROUGH WILL ERODE THE

SUBTROPICAL RIDGE TO THE NORTH OF WALAKA ON MONDAY AND STEER THE

TROPICAL CYCLONE NORTHWESTWARD, WITH A TURN TOWARD THE NORTH AND

NORTHEAST ALONG WITH AN INCREASE IN FORWARD SPEED FORECAST BEYOND

72 HOURS. THE GUIDANCE IS FAIRLY TIGHTLY CLUSTERED THROUGH 48 HOURS

WITH INCREASING MODEL SPREAD FROM FORECAST HOUR 72 ONWARD. THE

OFFICIAL FORECAST CLOSELY FOLLOWS THE GFEX AND TVCN CONSENSUS

MODELS THROUGH 48 HOURS, AND LIES NEARLY ON TOP OF THE TRACK FROM

THE PREVIOUS ADVISORY. BEYOND 48 HOURS, THE OFFICIAL FORECAST TRACK

WAS NUDGED TO THE RIGHT TO BETTER ALIGN WITH THE LATEST CONSENSUS