696 
 WTNT41 KNHC 170248
 TCDAT1
 
 TROPICAL DEPRESSION SIX DISCUSSION NUMBER   1
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL062016
 1100 PM AST TUE AUG 16 2016
 
 Convective activity associated with the tropical wave and associated
 low pressure area over the tropical Atlantic has become more
 concentrated and better organized this evening, and a recent ASCAT
 overpass indicates that the circulation has become better defined.
 Based on these data, this system has been designated a tropical
 depression, and advisories are being initiated at this time. The
 initial wind speed of 30 kt is supported by the scatterometer data.
 Some northeasterly shear is affecting the depression, with the
 center located near the northeastern edge of the primary convective
 mass.  The shear is forecast to decrease tonight and remain low
 during the next couple of days which favors strengthening. However,
 dry mid-level air is lurking just to the north of the depression,
 and intrusions of this unfavorable airmass could arrest development.
 The NHC forecast shows gradual strengthening during the next couple
 of days, but it is on the lower side of the guidance, closest to the
 LGEM and intensity consensus.  Later in the forecast period,
 increasing southwesterly shear being produced by a mid- to
 upper-level trough over the central Atlantic is likely to weaken the
 tropical cyclone.
 
 The initial motion estimate is a somewhat uncertain 310/12 kt.  The
 depression is forecast to move generally northwestward into a
 weakness in the subtropical ridge over the central Atlantic. The
 track guidance is in relatively good agreement through 48 hours, but
 there is a large spread between the GFS-based guidance and the ECMWF
 later in the period. The ECMWF and the majority of its ensemble
 members depict a much weaker and shallower cyclone that turns
 west-northwestward in the low-level flow after 48 hours.  On the
 other hand, the GFS, GFS ensemble mean, GFDL, and HWRF take a
 stronger cyclone more poleward.  For now, the NHC track is between
 these two distinct solutions, and is located just south of the
 multi-model consensus at days 4 and 5.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  17/0300Z 12.6N  34.1W   30 KT  35 MPH
  12H  17/1200Z 13.7N  35.6W   35 KT  40 MPH
  24H  18/0000Z 15.2N  37.2W   40 KT  45 MPH
  36H  18/1200Z 16.8N  38.8W   45 KT  50 MPH
  48H  19/0000Z 18.1N  40.2W   50 KT  60 MPH
  72H  20/0000Z 20.0N  43.2W   50 KT  60 MPH
  96H  21/0000Z 22.5N  46.5W   45 KT  50 MPH
 120H  22/0000Z 25.0N  50.0W   40 KT  45 MPH
 
 $$
 Forecaster Brown