000 WTPZ44 KNHC 310237 TCDEP4 Tropical Storm Lidia Discussion Number 6 NWS National Hurricane Center Miami FL EP142017 900 PM MDT Wed Aug 30 2017 Satellite images indicate that the circulation, although broad, is more consolidated, and convection has become more concentrated near the center. However, there is no evidence of an inner core at this time. Data from a unmanned NASA Global Hawk aircraft currently in the area of Lidia, and observations from the Mexican Navy automatic weather stations, were very helpful in determining the structure of the cyclone. The best estimate of the initial intensity is 35 kt. Lidia is within a very favorable environment of low shear, and the ocean is warm. The only factor against a higher intensification rate appears to be the large size of the cyclone. The NHC forecast calls for gradual strengthening during the next 12 to 24 hours, and Lidia has a chance to be near hurricane strength before the cyclone begins to interact with the high terrain of the Baja California peninsula. After that time, gradual weakening should then begin. The overall circulation is still moving toward the north-northwest or 345 degrees at 6 kt. Lidia is being steered by the flow between a weak ridge over Mexico and a weak cyclonic gyre to the west. This pattern will persist, and the cyclone should continue on the same general track for the next 2 days. Once the cyclone reaches the central portion of Baja California peninsula, a ridge to the north is forecast to amplify, and this flow pattern will force a weaker Lidia on a more west-northwest track toward cold waters. It is important to emphasize that Lidia is a large system accompanied by very heavy rains which are already occuring over portions of western Mexico and Baja California Sur. These rains are already causing threatening flash floods and mudslides and regardless of exactly how strong Lidia becomes, this should be a significant hazard. FORECAST POSITIONS AND MAX WINDS INIT 31/0300Z 20.7N 109.2W 35 KT 40 MPH 12H 31/1200Z 21.6N 109.5W 45 KT 50 MPH 24H 01/0000Z 22.8N 110.0W 55 KT 65 MPH 36H 01/1200Z 23.8N 110.6W 45 KT 50 MPH...INLAND 48H 02/0000Z 25.5N 111.7W 40 KT 45 MPH...INLAND 72H 03/0000Z 28.0N 114.3W 25 KT 30 MPH...INLAND 96H 04/0000Z 29.0N 117.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 05/0000Z 29.5N 119.5W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Avila