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| #1193591 (Received by flhurricane at: 4:36 AM 13.Aug.2024) TCDAT5 Tropical Storm Ernesto Discussion Number 7 NWS National Hurricane Center Miami FL AL052024 500 AM AST Tue Aug 13 2024 Satellite imagery and French radar data from Guadeloupe indicate that convection has become more concentrated near the center of Ernesto during the past several hours, and there is increased evidence of cyclonic rotation in the radar imagery. However, this has not yet resulted in significant intensification, with surface obs from the Leeward Islands showing a large area of pressures near 1007-1009 mb and no evidence of any tight wind center. Based on this and the latest satellite intensity estimates, the initial intensity is held at 35 kt. The initial motion is a somewhat uncertain 280/17, a little slower than before. Ernesto should turn west-northwestward with an additional decrease in forward speed during the next 12 h or so as it approaches a developing break in the subtropical ridge. This motion should bring the center near or over the Leeward Islands today and near or over the Virgin Islands and Puerto Rico tonight and early Wednesday. After that, the flow between the subtropical ridge and a mid-latitude trough moving eastward from the United States should cause the cyclone to turn northward and northeastward. By the end of the forecast period, this trough is expected to move eastward away from Ernesto, with a mid-latitude shortwave ridge passing north of the storm. This development should cause another decrease in forward speed during the 96-120 h period. The new forecast track is close to the various consensus models, and it is also similar to the previous forecast track. Ernesto is forecast to be in an environment of light to moderate shear and over warm sea surface temperatures through the forecast period, and this combination should allow it to strengthen. Intensification is likely to be slow during the first 12-24 h primarily due to the current lack of organization. After that, a faster rate of strengthening is expected, with Ernesto forecast to reach hurricane strength in 36-48 h. The intensity forecast follows the overall trend of the intensity guidance, and it lies between the intensity consensus and the upper edge of the guidance. Key Messages: 1. Ernesto is expected to bring tropical storm conditions to portions of the Leeward Islands today and to the Virgin Islands and Puerto Rico by late today or tonight. Tropical Storm Warnings are in effect for this entire area. 2. Heavy rainfall may result in locally considerable flash flooding and mudslides in areas of the Leeward Islands through today, and over the Virgin Islands into Puerto Rico by later today through Wednesday. 3. It is too soon to know what impacts Ernesto could bring to Bermuda late this week, and interests there should monitor the progress of this system. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 16.2N 61.3W 35 KT 40 MPH 12H 13/1800Z 17.1N 63.4W 40 KT 45 MPH 24H 14/0600Z 18.7N 65.7W 50 KT 60 MPH 36H 14/1800Z 20.7N 67.3W 60 KT 70 MPH 48H 15/0600Z 23.0N 68.3W 70 KT 80 MPH 60H 15/1800Z 25.1N 68.3W 80 KT 90 MPH 72H 16/0600Z 27.2N 67.3W 90 KT 105 MPH 96H 17/0600Z 30.5N 65.0W 95 KT 110 MPH 120H 18/0600Z 33.5N 64.5W 95 KT 110 MPH $$ Forecaster Beven |
