068 
 WTPA44 PHFO 080844
 TCDCP4
  
 Tropical Storm Norman Discussion Number  45
 NWS Central Pacific Hurricane Center Honolulu HI   EP162018
 1100 PM HST Fri Sep 07 2018
  
 The exposed low-level circulation center (LLCC) of Norman remains
 clearly evident in infrared and fog product satellite imagery this
 evening, with diminishing deep convection confined only to the
 northeast quadrant in a strongly sheared pattern. The subjective
 Dvorak current intensity estimate came in at 3.5/55 kt from PHFO,
 while JTWC estimated 3.0 or 45-50 kt using the subtropical method.
 Objective intensity estimates are lower, with CIMSS SATCON showing
 44 kt, and CIMSS ADT 2.8/41 kt. Recent satellite images since the
 06Z synoptic time also show the remaining deep convection becoming
 increasingly separated from the LLCC. Out of respect for the
 stronger winds found around midday today by the 53rd Weather
 Reconnaissance Squadron aircraft penetration as well as the 2001Z
 ASCAT pass, will lower the initial intensity for this advisory only
 slightly to 55 kt.   
 
 The initial motion estimate for this advisory is 335/8 kt. Norman 
 continues to move to the north-northwest between a deep-layer ridge 
 centered to the east, and a longwave trough to the northwest. The
 latest track guidance has shifted a bit more to the right, in better
 agreement with the motion of Norman during the past 18 hours or so,
 and shows the cyclone continuing on a north-northwest to northward
 course during the next 2 to 3 days. The new track forecast lies 
 close to the consensus HCCA and TVCE objective aids, and was shifted
 only slightly to the right from the previous forecast. 
 
 The CIMSS vertical wind shear estimate for this advisory is 230/56
 kt, and is supported by recent GOES satellite-derived upper-level
 wind retrievals. Very strong wind shear of 45-55 kt will persist
 over Norman for the next 36 hours, with some decrease possible
 thereafter. However, the system is forecast to be moving over cool
 SSTs below 25C by that time. The combined effects of the shear and
 increasingly cool water should cause Norman to steadily weaken
 to a remnant low by 72 hours, then dissipate by day 5. It is worth
 noting that the GFS and ECMWF models maintain Norman as a stronger
 system, possibly transitioning toward extratropical after 72 hours,
 while the hurricane dynamical and statistical models show more rapid
 weakening. The official intensity forecast compromises between these
 extremes, and delays dissipation as compared to the statistical
 guidance, but does not keep Norman as strong as the GFS/EC and does
 not show extratropical transition. If the recent loss of deep
 convection near the LLCC persists, Norman could become post-tropical
 considerable sooner than indicated in this forecast.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  08/0900Z 25.6N 153.6W   55 KT  65 MPH
  12H  08/1800Z 26.8N 154.0W   50 KT  60 MPH
  24H  09/0600Z 28.6N 154.3W   45 KT  50 MPH
  36H  09/1800Z 30.3N 154.3W   40 KT  45 MPH
  48H  10/0600Z 32.3N 154.0W   35 KT  40 MPH
  72H  11/0600Z 34.5N 154.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
  96H  12/0600Z 35.5N 156.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 120H  13/0600Z...DISSIPATED
  
 $$
 Forecaster Jacobson