WTPA44 PHFO 080240

TCDCP4



TROPICAL STORM JIMENA DISCUSSION NUMBER  50

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP132015

500 PM HST MON SEP 07 2015



JIMENA APPEARS TO BE A MESSY...VERTICALLY TILTED SYSTEM LATE THIS

AFTERNOON. AN SSMI PASS AT 0021 UTC AND AN AMSU-B PASS AT 0014

UTC SEEM TO SUGGEST THAT THE LOW LEVEL CENTER MAY BE MORE TO THE

WEST OF WHERE THE CONVENTIONAL SATELLITE IMAGERY WOULD INDICATE...

WHICH COULD BE A MID-LEVEL CENTER. THE OFFICIAL POSITION IS A

COMPROMISE AMONG THESE VARIOUS POSITIONS. UNANIMOUS SUBJECTIVE

INTENSITY ESTIMATES OF 2.5...AND CIMSS ADT WAS 2.4. THIS...ALONG

WITH A SLOWLY DEGRADING BANDED STRUCTURE TO THE CONVECTION WHICH

MIGHT NOT EVEN BE FOLLOWING THE LOW LEVEL CENTER ANYMORE...IS THE

BASIS FOR LOWERING THE ADVISORY INTENSITY TO 40 KT.



THE INITIAL MOTION ESTIMATE IS A RATHER UNCERTAIN 290/6...DRIVEN

MAINLY BY A HIGH AT THE SURFACE AND ALOFT TO THE NORTHEAST OF THE

CYCLONE. JIMENA CONTINUES TO STRUGGLE THROUGH RELENTLESS WESTERLY

SHEAR OF 20 TO 30 KT...WHICH IS ONLY EXPECTED TO INCREASE ALONG THE

FORECAST TRACK. THIS SHEAR ALONG WITH MARGINAL SEA SURFACE

TEMPERATURES IS EXPECTED TO LEAD TO ADDITIONAL SLOW WEAKENING. THE

MODELS ARE CONTINUING TO SHOW THE LOW AND MID-LEVEL CIRCULATIONS

BECOMING INCREASINGLY DECOUPLED...AND SEPARATING IN ABOUT 24 HOURS

OR SO. AT THIS POINT JIMENA WILL BE STEERED BY THE SHALLOW LAYER

FLOW WHICH WILL TAKE THE CYCLONE JUST SOUTH OF DUE WEST FOR A TIME...

BEFORE LOW PRESSURE DEVELOPING NORTH OF LAYSAN PICKS UP WHAT

REMAINS OF THE CIRCULATION AND TURNS IT NORTHWARD ON DAYS 3-5. THE

TRACK GUIDANCE SHIFTED A LITTLE TO THE WEST AND SOUTH ONCE AGAIN...

LIKELY BECAUSE OF INCREASING CONFIDENCE IN JIMENA/S WEAKER STATE AT

THAT TIME...AND ADJUSTED OUR FORECAST TO MATCH THAT TREND AS WELL.

JIMENA IS STILL FORECAST TO BECOME A REMNANT LOW BY DAY 4...BUT THIS

COULD OCCUR SOONER.





FORECAST POSITIONS AND MAX WINDS



INIT  08/0300Z 26.5N 150.9W   40 KT  45 MPH

 12H  08/1200Z 26.6N 151.8W   40 KT  45 MPH

 24H  09/0000Z 26.4N 153.4W   35 KT  40 MPH

 36H  09/1200Z 26.1N 154.9W   35 KT  40 MPH

 48H  10/0000Z 26.0N 156.5W   30 KT  35 MPH

 72H  11/0000Z 26.1N 159.3W   25 KT  30 MPH

 96H  12/0000Z 26.5N 161.8W   25 KT  30 MPH...POST-TROP/REMNT LOW

120H  13/0000Z 29.0N 163.4W   20 KT  25 MPH...POST-TROP/REMNT LOW



$$

FORECASTER R BALLARD