069 
 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