WTPA42 PHFO 042044

TCDCP2



TROPICAL STORM OHO DISCUSSION NUMBER   7

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP072015

1100 AM HST SUN OCT 04 2015



OVERALL SYSTEM ORGANIZATION HAS IMPROVED A BIT SINCE LAST

NIGHT...WITH THE LOW LEVEL CIRCULATION CENTER...LLCC...LOCATED ON

THE EASTERN EDGE OF DEEP CONVECTION. ADDITIONAL RAINBANDS ARE

FORMING ACROSS THE NORTHEAST QUADRANT...AND ANIMATION OF THESE IN

THE FEW VISIBLE IMAGES AVAILABLE INCREASES FIX CONFIDENCE.

SUBJECTIVE DVORAK SATELLITE INTENSITY ESTIMATES RANGE FROM 2.0...30

KT...FROM PHFO AND SAB TO 2.5...35 KT...FROM JTWC. UW-CIMSS ADT WAS

HIGHEST AT 2.7...39 KT. THE BEST CHOICE FOR INITIAL INTENSITY IS A

BLEND OF THESE...AND WE WILL KEEP OHO AS A 35 KT TROPICAL STORM FOR

THIS ADVISORY.



OHO CONTINUES TO MEANDER TO THE SOUTH OF THE HAWAIIAN ISLANDS THIS

MORNING...AND THE INITIAL MOTION OF 360/02 KT MAY BE JUST A SNAPSHOT

OF THIS MEANDERING. UW-CIMSS AND SHIPS ANALYSIS SHOW EASTERLY SHEAR

ACROSS OHO RANGES FROM 10 TO 15 KT...SO IT MAKES SENSE THAT

ASSOCIATED DEEP CONVECTION LIES WEST OF THE LLCC AND THAT THE CORE

IS TILTED TOWARD THE WEST WITH HEIGHT. THIS TILTING ADDS

UNCERTAINTY TO MOTION IN SPITE OF VISIBLE IMAGE ANIMATION. STEERING

INFLUENCES ARE WEAK AND INCLUDE A MID-LEVEL RIDGE WHICH EXTENDS

WESTWARD FROM THE EASTERN PACIFIC AND THE FIRST GENTLE NUDGES FROM A

DEEP TROUGH DEVELOPING NORTHWEST OF THE HAWAIIAN ISLANDS. WHILE

FORECAST TRACK GUIDANCE REMAINS CLUSTERED AROUND NORTHERLY MOTION

TODAY BECOMING NORTHEASTERLY MOTION MONDAY AND AFTERWARDS...FORWARD

SPEED BETWEEN MODELS VARIES WIDELY...WITH ECMWF DEPICTING LONG RANGE

FORWARD SPEED ABOUT DOUBLE WHAT GFS DEPICTS. THIS IS LIKELY DUE TO

DIFFERENCES IN HOW EACH MODEL SEES THE INTERACTION BETWEEN OHO AND

THE EXPECTED DEEP TROUGHING NORTH OF HAWAII BEYOND 48 HOURS...AND

WITH THE INTERACTION WITH ANOTHER LOW FARTHER TO THE EAST. THE

CURRENT FORECAST TRACK CLOSELY ALIGNS WITH THE PREVIOUS ONE THROUGH

72 HOURS...THEN IS ADJUSTED TO THE LEFT AT 96 AND 120 HOURS TO

REMAIN WITHIN THE CONSENSUS ENVELOPE.



INTENSITY GUIDANCE CONTINUES TO INDICATE THAT OHO WILL REMAIN A

TROPICAL STORM THROUGH THE FORECAST PERIOD...IN SPITE OF MOVING

ACROSS 28C TO 29C WATER THROUGH 48 HOURS. SHEAR IS EXPECTED TO

INCREASE DRAMATICALLY ACROSS OHO BEYOND 48 HOURS AS THE DEEP TROUGH

NORTH OF HAWAII DIGS SOUTHEASTWARD AND BEGINS TO SCOOP THIS SYSTEM

OUT OF THE DEEP TROPICS. HOWEVER...SOME STRENGTHENING IS EXPECTED

UNTIL THEN AS SHEAR REMAINS MODERATE TODAY...THEN ACTUALLY

DECREASES TEMPORARILY MONDAY. THE INTENSITY TREND FOR THIS ADVISORY

CLOSELY FOLLOWS THE PREVIOUS ONE...BUT CAPS INTENSITY AT 55 KT.

THIS IS SLIGHTLY HIGHER THAN SHIPS BUT BELOW HWRF AND GFDL.



THE 53RD WEATHER RECONNAISSANCE SQUADRON HAS BEEN TASKED TO FLY THIS

SYSTEM IN SUPPORT OF CPHC OPERATIONS. INITIAL FLIGHTS INTO THE

SYSTEM ARE PLANNED FOR THIS EVENING AND MONDAY MORNING.

ADDITIONALLY...THE G-IV AIRCRAFT WILL FLY SYNOPTIC MISSIONS...WITH

A HIGH-ALTITUDE FLIGHT PLANNED MONDAY MORNING...IN ORDER FOR THE

DATA TO BE UTILIZED BY AFTERNOON MODEL RUNS.





FORECAST POSITIONS AND MAX WINDS



INIT  04/2100Z 13.6N 154.9W   35 KT  40 MPH

 12H  05/0600Z 14.0N 155.0W   40 KT  45 MPH

 24H  05/1800Z 14.6N 154.6W   45 KT  50 MPH

 36H  06/0600Z 15.5N 153.8W   50 KT  60 MPH

 48H  06/1800Z 16.3N 152.7W   55 KT  65 MPH

 72H  07/1800Z 18.3N 150.5W   55 KT  65 MPH

 96H  08/1800Z 22.0N 148.3W   55 KT  65 MPH

120H  09/1800Z 26.2N 146.2W   50 KT  60 MPH



$$

FORECASTER POWELL