WTPA41 PHFO 300253 RRA

TCDCP1



TROPICAL STORM WALAKA DISCUSSION NUMBER   2

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP012018

500 PM HST SAT SEP 29 2018



THE SATELLITE PRESENTATION OF WALAKA HAS NOT CHANGED SIGNIFICANTLY

SINCE THIS MORNING. THE BANDING FEATURE TO THE EAST AND SOUTH OF THE

CENTER HAS BECOME LESS DISTINCT, THOUGH A LARGE AREA OF DEEP

CONVECTION HAS PERSISTED NEAR THE CENTER. SUBJECTIVE DVORAK CURRENT

INTENSITY ESTIMATES RANGE FROM 2.0/30 KT OUT OF JTWC TO 2.5/35 KT

FROM HFO AND SAB. THE INITIAL INTENSITY WILL BE HELD AT 35 KT FOR

THIS ADVISORY.



WALAKA CONTINUES TO MOVE TOWARD THE WEST (265 DEGREES) AT 13 KT. A

DEEP RIDGE TO THE NORTH WILL STEER WALAKA ON A GENERAL WESTWARD

MOTION THROUGH SUNDAY, TAKING THE CYCLONE WELL SOUTHWEST OF THE MAIN

HAWAIIAN ISLANDS. LATE SUNDAY THROUGH MONDAY NIGHT, WALAKA WILL MAKE

A GRADUAL TURN TOWARD THE NORTHWEST THEN NORTH AS A DEEP NORTH

PACIFIC TROUGH DIGS SOUTHWARD AND STEADILY ERODES THE RIDGE. AS A

RESULT, WALAKA WILL PASS VERY CLOSE TO, OR OVER, JOHNSTON ATOLL AS

EARLY AS MONDAY NIGHT AND LIKELY ON TUESDAY. THE DEEP TROUGH WILL

STALL ROUGHLY ALONG 171W LONGITUDE ON TUESDAY, AND AS INTERACTION

WITH THE TROUGH INCREASES, WALAKA WILL ACCELERATE NORTHWARD ON DAYS

FOUR AND FIVE. THIS SHOULD TAKE THE SYSTEM ACROSS THE

PAPAHANAUMOKUAKEA MARINE NATIONAL MONUMENT. THE TRACK GUIDANCE

ENVELOPE IS TIGHTLY CLUSTERED THROUGH 72 HOURS, WITH DIFFERENCES IN

FORWARD MOTION INCREASING THEREAFTER. THROUGH 72 HOURS, THE TRACK

FORECAST IS ESSENTIALLY UNCHANGED AND LIES NEAR THE MIDDLE OF THE

TIGHTLY CLUSTERED GUIDANCE ENVELOPE. ON DAYS FOUR AND FIVE, THE

FORECAST FORWARD MOTION HAS BEEN ACCELERATED TO FOLLOW THE TVCE