000 WTPZ42 KNHC 182034 TCDEP2 Tropical Storm Greg Discussion Number 6 NWS National Hurricane Center Miami FL EP072017 300 PM MDT Tue Jul 18 2017 Satellite imagery suggests that the circulation of Greg has become better defined today. However, the earlier dense convective overcast has dissipated, leaving a small area of convection near the center and some thin outer banding. Subjective satellite intensity estimates from TAFB and SAB are 35 kt, while estimates based on microwave sounder data are 40-45 kt. Based on the current convective trends, the initial intensity remains 35 kt, and it is possible this is conservative. Water vapor imagery indicates that upper-level westerlies produced by the outflow of Hurricane Fernanda and Tropical Depression Eight-E are impinging on the western side of Greg, although the analyzed vertical shear is currently low. The initial motion is 275/8. For the first 48 h, Greg should move generally westward to the south of a mid-level ridge. After that, the forecast becomes low confidence due to interaction, and possible merger, with Tropical Depression Eight-E. The large-scale models are showing run-to-run inconsistency on which of the cyclones will be dominant during this process and which might get destroyed. The current forecast scenario is that both systems will survive, with Greg moving quickly around the north semicircle of the circulation of Eight-E. The new forecast track is near the model consensus through 72 h and north of the model consensus after that time. A combination of light/moderate vertical wind shear and warm sea surface temperatures should allow Greg to slowly strengthen during the first 36-48 h. After that, the intensity forecast also becomes low confidence due to the interaction with Tropical Depression Eight-E. The forecast track takes Greg over decreasing sea surface temperatures after 48-60 h, and on this basis the intensity forecast shows a weakening trend. However, an alternate forecast scenario is for Greg to weaken faster than currently forecast during the cyclone interaction. The new forecast follows the trend of the guidance and is a little above the intensity consensus. FORECAST POSITIONS AND MAX WINDS INIT 18/2100Z 14.6N 109.0W 35 KT 40 MPH 12H 19/0600Z 14.8N 110.3W 40 KT 45 MPH 24H 19/1800Z 15.2N 112.4W 45 KT 50 MPH 36H 20/0600Z 15.6N 114.5W 50 KT 60 MPH 48H 20/1800Z 16.2N 117.0W 50 KT 60 MPH 72H 21/1800Z 17.5N 122.5W 40 KT 45 MPH 96H 22/1800Z 17.5N 127.5W 30 KT 35 MPH 120H 23/1800Z 16.5N 131.5W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Beven