233 
 WTNT41 KNHC 180244
 TCDAT1
 
 TROPICAL STORM FIONA DISCUSSION NUMBER   5
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL062016
 1100 PM AST WED AUG 17 2016
 
 For a time late this afternoon, it seemed that Fiona might lose all
 its deep convection.  However, a new burst developed around 2300 UTC
 and has persisted since that time.  An 0026 UTC ASCAT-B pass
 revealed that the cyclone is still producing a small area of
 tropical-storm-force winds, and the intensity remains 35 kt.
 
 Fiona has a tough road ahead.  Vertical shear right now is
 relatively low, but it is expected to begin increasing within the
 next 24 hours and then become belligerent out of the southwest by
 days 3 and 4.  In addition, the cyclone is surrounded by dry air,
 and any negative impacts that the dry air is already having on the
 convection is likely to be compounded once the shear increases in a
 few days.  With the exception of the GFDL, which makes Fiona a
 hurricane by the end of the forecast period, the rest of the
 intensity models respond to the unfavorable environment by showing
 relatively little strengthening.  The NHC forecast follows this same
 thinking, and it shows Fiona only modestly strengthening during the
 next 36 hours, with some weakening probable by day 3.  Based on the
 latest intensity guidance, the new NHC forecast has been adjusted
 downward from the previous forecast, but it still lies above the
 consensus at most forecast times.
 
 The recent ASCAT data helped to fix the center, and the initial
 motion estimate is now west-northwestward, or 300/14 kt.  A break
 in the mid-tropospheric ridge to the north of Fiona is expected to
 to migrate westward during the next few days, but the cyclone's
 shallow nature is expected to help maintain a west-northwestward
 motion for much of the forecast period.  The bulk of the track
 models are tightly clustered on such a heading.  However, the GFDL
 (which makes Fiona hurricane) shows a sharp northward turn, while
 the HWRF (which essentially shows no intensification) takes a much
 more southern track.  Since these two scenarios appear to cancel
 each other out, the NHC official forecast closely follows the
 consensus models, requiring a westward adjustment to the previous
 forecast.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  18/0300Z 15.5N  39.0W   35 KT  40 MPH
  12H  18/1200Z 16.3N  40.4W   35 KT  40 MPH
  24H  19/0000Z 17.1N  41.9W   40 KT  45 MPH
  36H  19/1200Z 17.8N  43.5W   45 KT  50 MPH
  48H  20/0000Z 18.6N  45.2W   45 KT  50 MPH
  72H  21/0000Z 20.6N  49.1W   40 KT  45 MPH
  96H  22/0000Z 22.5N  53.0W   40 KT  45 MPH
 120H  23/0000Z 24.5N  57.0W   40 KT  45 MPH
 
 $$
 Forecaster Berg