WTPA41 PHFO 010254 RRA

TCDCP1



HURRICANE WALAKA DISCUSSION NUMBER   6

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP012018

500 PM HST SUN SEP 30 2018



WALAKA'S WELL DEFINED DEEP CONVECTIVE WRAPPING PATTERN HAS MORPHED

INTO A CLOUDY EYE PATTERN IN VISIBLE IMAGERY THIS AFTERNOON.

SATELLITE LOOP SHOWS SYSTEM OUTFLOW IS GOOD ACROSS ALL QUADRANTS

AND OVERALL SYSTEM SYMMETRY AND ORGANIZATION CONTINUE TO IMPROVE.

SUBJECTIVE DVORAK CURRENT INTENSITY (CI) ESTIMATES RANGE FROM

4.0/65 KT FROM JTWC AND PHFO TO 4.5/77 KT FROM SAB. ADT FROM

UW-CIMSS IS 68 KT. GIVEN THE PRESENCE OF A CLOUDY EYE AND HIGHER

OVERALL CI ESTIMATES FROM THE ANALYSIS CENTERS, WE WILL SET THE

INITIAL INTENSITY AT 65 KT FOR THIS ADVISORY. WALAKA IS NOW A

HURRICANE.



THE OVERALL FORECAST PHILOSOPHY FOR WALAKA IS UNCHANGED. THIS

SYSTEM CONTINUES MOVING SLIGHTLY NORTH OF DUE WEST ALONG THE

SOUTHERN FLANK OF THE SUBTROPICAL RIDGE. GLOBAL MODELS SHOW A DEEP

UPPER TROUGH WILL DIG SOUTHWARD, ERODING THE WESTERN EDGE OF THE

SUBTROPICAL RIDGE TO THE NORTH OF WALAKA ON MONDAY. THIS WILL STEER

WALAKA NORTHWESTWARD, THEN NORTHWARD ON TUESDAY. TRACK GUIDANCE

REMAINS VERY TIGHTLY CLUSTERED THROUGH FRIDAY, GREATLY INCREASING

CONFIDENCE IN THE TIMING OF THE CURVE NORTHWARD. OUR FORECAST

CLOSELY FOLLOWS THE PREVIOUS ONE, WITH ANOTHER TAP TO THE WEST FROM

12 TO 36 HOURS NEEDED TO STAY WITHIN THE VERY TIGHT GUIDANCE

ENVELOPE. A SMALL TAP TO THE EAST AT 72 HOURS WAS NEEDED FOR THE

SAME REASON. WITH THE OFFICIAL FORECAST TRACK BRINGING THE CENTER OF

WALAKA VERY NEAR JOHNSTON ATOLL ON TUESDAY, A HURRICANE WARNING IS

NOW IN EFFECT THERE.



WALAKA REMAINS WITHIN IDEAL CONDITIONS FOR STRENGTHENING, WITH HIGH