369 
 WTPZ45 KNHC 050836
 TCDEP5
 
 TROPICAL STORM IVETTE DISCUSSION NUMBER  11
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP102016
 200 AM PDT FRI AUG 05 2016
 
 There has been little change in the convective organization of
 Ivette overnight.  The low-level center remains exposed to the
 west and northwest of a loosely curved band of thunderstorms, due
 to westerly to northwesterly shear.  Subjective and objective
 Dvorak T-numbers are all near T3.0, which yields an initial
 wind speed of 45 kt.  Although the shear is not very strong, it
 appears the small size of the cyclone and perhaps some nearby dry
 mid-level air in combination with the shear have prevented
 intensification during the past day.  The GFS-based SHIPS guidance
 indicates that the shear will decrease during the next 24 hours or
 so, but the ECMWF model shows a continuation of some upper-level
 westerlies over Ivette.  Because of these differences in the
 expected upper-level winds, the NHC intensity forecast is more
 uncertain than normal.  The updated intensity forecast calls for
 some slight strengthening during the next 36 hours, but it is lower
 than the previous advisory, and it is closest to the IVCN intensity
 consensus.  After 48 h, increasing southwesterly shear and cooler
 SSTs should cause a fairly rapid spin down of Ivette, and the
 cyclone is likely to become a remnant low in 4 to 5 days.
 
 The tropical storm is moving westward or 275/12 kt.  Ivette should
 turn west-northwestward in 12 to 24 hours as a deepening mid- to
 upper-level trough to the north of the Hawaiian Islands weakens the
 western portion of the subtropical ridge.  After day 3, Ivette is
 forecast to turn back westward after it weakens and is steered by
 the low-level easterly trades.  There remains high confidence in the
 track forecast since the dynamical models continue to be in good
 agreement.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  05/0900Z 14.9N 129.7W   45 KT  50 MPH
  12H  05/1800Z 15.2N 131.2W   45 KT  50 MPH
  24H  06/0600Z 15.8N 133.1W   50 KT  60 MPH
  36H  06/1800Z 16.4N 134.8W   55 KT  65 MPH
  48H  07/0600Z 17.2N 136.5W   55 KT  65 MPH
  72H  08/0600Z 18.5N 139.5W   40 KT  45 MPH
  96H  09/0600Z 19.0N 142.7W   30 KT  35 MPH
 120H  10/0600Z 18.8N 146.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
 $$
 Forecaster Brown