ZCZC MIATCDAT2 ALL TTAA00 KNHC DDHHMM Potential Tropical Cyclone Seven Discussion Number 1 NWS National Hurricane Center Miami FL AL072017 500 PM EDT Sun Aug 06 2017 Surface and scatterometer data indicate that the broad area of low pressure over the northwestern Caribbean Sea still lacks a well-defined center of circulation. However, this system is likely to become a tropical storm before reaching the coast of the Yucatan Peninsula late tomorrow, and advisories are being initiated to enable the issuance of a tropical storm warning and watch for Yucatan and Belize respectively. The scatterometer pass and NOAA data buoy observations indicate that the maximum winds are near 30 kt. The disturbance has been experiencing westerly vertical shear due to a nearby upper-level low and this has been inhibiting development. Global model predictions show that this low will soon dissipate and an upper-level anticyclone will become established over the area. Therefore, strengthening is likely with the main impediment being interaction with land. The official intensity forecast is a little above the model consensus. It should be noted that the system could become a hurricane between 72 and 96 hours, i.e. prior to reaching the Gulf coast of Mexico. Since the center lacks definition, the initial location and motion are quite uncertain, and my best guess for the current motion is 290/10. The steering pattern for the disturbance/tropical cyclone is expected to be fairly straightforward and persistent for the next few days. A general west-northwestward track is expected to continue until landfall in mainland Mexico. The official track forecast is generally a blend of the latest GFS and ECMWF solutions. FORECAST POSITIONS AND MAX WINDS INIT 06/2100Z 15.6N 82.0W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 12H 07/0600Z 16.6N 83.6W 35 KT 40 MPH...TROPICAL CYCLONE 24H 07/1800Z 18.0N 85.9W 45 KT 50 MPH 36H 08/0600Z 19.0N 88.0W 45 KT 50 MPH...INLAND 48H 08/1800Z 19.9N 90.1W 35 KT 40 MPH...INLAND 72H 09/1800Z 21.0N 93.8W 60 KT 70 MPH...OVER WATER 96H 10/1800Z 21.2N 97.8W 60 KT 70 MPH...INLAND 120H 11/1800Z...DISSIPATED $$ Forecaster Pasch NNNN