000WTNT41 KNHC 170248TCDAT1TROPICAL DEPRESSION SIX DISCUSSION NUMBER 1NWS NATIONAL HURRICANE CENTER MIAMI FL AL0620161100 PM AST TUE AUG 16 2016Convective activity associated with the tropical wave and associatedlow pressure area over the tropical Atlantic has become moreconcentrated and better organized this evening, and a recent ASCAToverpass indicates that the circulation has become better defined.Based on these data, this system has been designated a tropicaldepression, and advisories are being initiated at this time. Theinitial wind speed of 30 kt is supported by the scatterometer data.Some northeasterly shear is affecting the depression, with thecenter located near the northeastern edge of the primary convectivemass. The shear is forecast to decrease tonight and remain lowduring 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 coupleof days, but it is on the lower side of the guidance, closest to theLGEM and intensity consensus. Later in the forecast period,increasing southwesterly shear being produced by a mid- toupper-level trough over the central Atlantic is likely to weaken thetropical cyclone.The initial motion estimate is a somewhat uncertain 310/12 kt. Thedepression is forecast to move generally northwestward into aweakness in the subtropical ridge over the central Atlantic. Thetrack guidance is in relatively good agreement through 48 hours, butthere is a large spread between the GFS-based guidance and the ECMWFlater in the period. The ECMWF and the majority of its ensemblemembers depict a much weaker and shallower cyclone that turnswest-northwestward in the low-level flow after 48 hours. On theother hand, the GFS, GFS ensemble mean, GFDL, and HWRF take astronger cyclone more poleward. For now, the NHC track is betweenthese two distinct solutions, and is located just south of themulti-model consensus at days 4 and 5.FORECAST POSITIONS AND MAX WINDSINIT 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 MPH120H 22/0000Z 25.0N 50.0W 40 KT 45 MPH$$Forecaster Brown