WTPA41 PHFO 010925 RRA

TCDCP1



HURRICANE WALAKA DISCUSSION NUMBER   7

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP012018

1100 PM HST SUN SEP 30 2018



WALAKA IS UNDERGOING RAPID INTENSIFICATION THIS EVENING, WHICH IS

CLEARLY EVIDENT GIVEN THE LARGE RING OF -70 TO -85C CLOUD TOPS

SURROUNDING THE THE WELL DEFINED EYE. ADDITIONALLY, RECENT

MICROWAVE PASSES INDICATE THAT THE ORGANIZATION OF THE SYSTEM HAS

IMPROVED SIGNIFICANTLY, WHILE GEOSTATIONARY SATELLITE ANIMATIONS

SHOW WELL DEFINED OUTFLOW CHANNELS IN ALL QUADRANTS. THE LATEST

INTENSITY ESTIMATES CAME IN AT 5.0 (90 KNOTS) FROM PHFO AND SAB, 4.5

(77 KNOTS) FROM JTWC, WHILE THE UW-CIMSS ADT WAS 4.2 (70 KNOTS).

BASED ON THE SIGNIFICANT IMPROVEMENT IN APPEARANCE AND ORGANIZATION

OF WALAKA, THE INITIAL INTENSITY FOR THIS ADVISORY WAS INCREASED TO

90 KNOTS. THE INITIAL MOTION WAS SET AT 280/10 KNOTS.



WALAKA CONTINUES TO BE STEERED WESTWARD THIS EVENING BY A

SUBTROPICAL RIDGE TO THE NORTH OF THE SYSTEM, AND THIS MOTION IS

EXPECTED TO CONTINUE TONIGHT. A TURN TOWARD THE NORTHWEST IS

EXPECTED ON MONDAY AS A DEEP NORTH PACIFIC UPPER TROUGH DIGS

SOUTHWARD IN THE VICINITY OF 30N 170W. A TURN TOWARD THE NORTH IS

THEN EXPECTED ON TUESDAY, WITH WALAKA CONTINUING ON THIS COURSE

THROUGH TUESDAY NIGHT WITH AN INCREASE IN FORWARD SPEED. THE

TROPICAL CYCLONE SHOULD THEN MAKE A TURN TOWARD THE NORTH-NORTHEAST

WEDNESDAY AND WEDNESDAY NIGHT AS IT BEGINS TO FEEL THE INFLUENCE OF

THE DEEP UPPER LEVEL TROUGH. THE TRACK GUIDANCE THEN SUGGESTS A

SHIFT BACK TOWARD THE NORTH WITH A DECREASE IN FORWARD SPEED

THURSDAY THROUGH FRIDAY AS WALAKA INTERACTS WITH THE DEEP UPPER

LEVEL TROUGH. THE OFFICIAL FORECAST WAS NUDGED SLIGHTLY TO THE LEFT