594 
 WTNT45 KNHC 131437
 TCDAT5
 
 Subtropical Storm Joyce Discussion Number   4
 NWS National Hurricane Center Miami FL       AL102018
 1100 AM AST Thu Sep 13 2018
 
 Joyce's satellite presentation is less than impressive this morning,
 with the low-level center exposed to the northwest of a small patch
 of deep convection. The initial intensity is set to 35 kt based on
 the latest subtropical classification of ST2.5 from TAFB a 1208Z
 ASCAT-B overpass that showed 30-35 kt winds north and northeast of
 the center. Cyclone phase space diagrams still show Joyce with a
 shallow-to-moderate warm core, and the system remains a subtropical
 storm for now.
 
 Little change in intensity is expected during the next few days, as
 Joyce will continue to be affected by strong westerly-to-
 southwesterly vertical wind shear. The new NHC forecast is a little
 below the intensity consensus given the weakening trend seen in the
 global models. Dissipation is shown at 96 hours, but it wouldn't be
 surprising if Joyce becomes a post-tropical cyclone before that.
 
 The initial motion estimate is 245/05. Joyce is currently situated
 a little to the west of an upper-level low, which is currently
 steering the system southwestward and southward, and that should
 continue for the next day or so. Then, Joyce should begin to
 accelerate northeastward ahead of an approaching mid-level trough.
 The new NHC track forecast follows the trend of the latest
 guidance, and is a little to the west of the previous one through
 36 hours. The official forecast is close to the latest HCCA and
 TVCA consensus aids.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  13/1500Z 33.7N  43.7W   35 KT  40 MPH
  12H  14/0000Z 33.1N  44.1W   35 KT  40 MPH
  24H  14/1200Z 32.2N  44.4W   40 KT  45 MPH
  36H  15/0000Z 31.9N  44.0W   40 KT  45 MPH
  48H  15/1200Z 32.5N  42.6W   40 KT  45 MPH
  72H  16/1200Z 35.5N  38.5W   35 KT  40 MPH
  96H  17/1200Z...DISSIPATED
 
 $$
 Forecaster Brennan