513 
 WTNT43 KNHC 091440
 TCDAT3
 
 Tropical Storm Leslie Discussion Number  53
 NWS National Hurricane Center Miami FL       AL132018
 1100 AM AST Tue Oct 09 2018
 
 Recent Dvorak fixes and ASCAT data indicate that Leslie's maximum
 winds remain around 55 kt. Although the winds have not yet
 increased, the surface center of the tropical storm has become more
 embedded within its cold cloud tops and several recent microwave
 overpasses indicate that the cyclone is beginning to establish an
 inner-core. Strengthening is therefore still expected, and Leslie is
 forecast to become a hurricane by tomorrow. The tropical storm is
 currently moving south-southeastward at around 11 kt, and the models
 are in good agreement that a south-southeastward to southward motion
 will continue for the next 24 h or so.
 
 Beginning around 36 h, both the track and intensity forecasts become
 very uncertain.  In general, most of the global models and their
 ensembles indicate that Leslie will begin to accelerate toward the
 east-northeast or northeast by Thursday as a mid-latitude trough
 approaches from the northwest, however the timing and extent of the
 interaction is still highly variable from model to model. Based on
 the GFS and ECMWF ensembles, a range of possibilities exists, from
 Leslie essentially merging with this trough and becoming
 extratropical over the far northeast Atlantic, to Leslie interacting
 with the trough very little and continuing to meander over the
 central Atlantic.  There has been a significant change in the
 consensus aids to show a slower track for Leslie based on recent
 shifts in the deterministic models, but the NHC track forecast has
 not been changed nearly as much, out of respect for continuity and
 the high uncertainty in the forecast.
 
 The low confidence in the track forecast beyond 36 h affects the
 intensity forecast as well, since it is unclear what environment the
 storm will be located within.  The intensity forecast is therefore
 held near the intensity consensus, and still calls for steady
 strengthening during the next several days, followed by weakening by
 the end of the forecast period.  If Leslie moves as far east as
 shown in the NHC track forecast, it would likely become a post-
 tropical low by day 5, as shown explicitly in the forecast. However,
 until confidence in the track increases, I can't rule out that
 Leslie could remain a tropical cyclone almost indefinitely if it
 continues meandering over the northern Atlantic.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  09/1500Z 31.3N  43.5W   55 KT  65 MPH
  12H  10/0000Z 29.9N  42.9W   55 KT  65 MPH
  24H  10/1200Z 28.5N  42.6W   60 KT  70 MPH
  36H  11/0000Z 28.1N  41.7W   65 KT  75 MPH
  48H  11/1200Z 28.9N  39.5W   70 KT  80 MPH
  72H  12/1200Z 32.0N  31.5W   75 KT  85 MPH
  96H  13/1200Z 33.5N  22.0W   65 KT  75 MPH
 120H  14/1200Z 33.5N  18.0W   50 KT  60 MPH...POST-TROPICAL
 
 $$
 Forecaster Zelinsky