ZCZC MIATCDEP3 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION THREE-E DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032015 400 PM CDT WED JUN 10 2015 Satellite imagery indicates that the deep convection associated with the low pressure system located southwest of the Gulf of Tehuantepec has become sufficiently well organized to designate the formation of a tropical depression. Therefore, advisories are being initiated at this time. The cyclone should remain in an environment of low vertical shear and over warm waters for the next several days, so steady strengthening seems to be a good bet. The official wind speed forecast is generally above the intensity model consensus. There is significant uncertainty in the longer range intensity forecast, depending on how much the system interacts with land. Center fixes have had a fair amount of scatter, and my best estimate of the initial motion is 315/8 kt. During the next 72 hours, the cyclone is likely to respond to a mid-level weakness over the Gulf of Mexico by turning northward and north-northeastward. Later in the forecast period, a mid-level ridge to the northwest is expected to cause the system to turn toward the west-northwest and move parallel the coast. The GFS model takes the system close to the coast in 72 hours, but the ECMWF and GFDL model tracks keep the cyclone offshore and are much farther to the west than the GFS solution. As a compromise, the official track forecast is close to the model consensus TVCN albeit not as far west as TVCN by 120 hours. Given the large divergence of the model tracks, this is a low confidence forecast. FORECAST POSITIONS AND MAX WINDS INIT 10/2100Z 12.4N 98.7W 30 KT 35 MPH 12H 11/0600Z 13.0N 99.4W 35 KT 40 MPH 24H 11/1800Z 13.4N 99.9W 45 KT 50 MPH 36H 12/0600Z 14.0N 99.6W 55 KT 65 MPH 48H 12/1800Z 14.5N 99.2W 65 KT 75 MPH 72H 13/1800Z 15.5N 99.0W 70 KT 80 MPH 96H 14/1800Z 16.5N 100.5W 75 KT 85 MPH 120H 15/1800Z 17.5N 103.5W 75 KT 85 MPH $$ Forecaster Pasch NNNN