213 WTNT45 KNHC 190234 TCDAT5 Hurricane Ernesto Discussion Number 30 NWS National Hurricane Center Miami FL AL052024 1100 PM AST Sun Aug 18 2024 Ernesto continues to have a good structure this evening with a partly cloud-filled eye surrounded by bands of convection, although the convective cloud tops are not quite as cold as they were 6 h ago. Subjective Dvorak intensity estimates from TAFB and SAB are now near 65 kt, while various objective estimates are now near 75 kt. The initial intensity is increased to 70 kt based on a blend of these data. Some additional strengthening is possible during the next 6-12 h before Ernesto moves north of the north wall of the Gulf Stream. After that, the system should quickly decay as it moves over colder water and encounters increasing southwesterly shear. The cyclone should become an extratropical low by 36 h as it passes south of southeastern Newfoundland, and by 72 h it should be absorbed into a larger non-tropical low developing south of Iceland. The new intensity forecast is near the upper edge of the intensity guidance for the first 12 h, and after that lies near the intensity consensus. The initial motion is now 030/17 kt. A northeastward motion at a faster forward speed is expected over the next 24-36 h as Ernesto becomes caught up in the flow between a large deep-layer trough over the eastern U.S. and a subtropical ridge centered to the hurricane's southeast. This motion should bring the center south of southeastern Newfoundland late Monday night or early Tuesday morning, with most of the wind field staying offshore. A more east-northeastward motion is expected thereafter before the cyclone becomes absorbed by the aforementioned larger extratropical cyclone. The tightly clustered track guidance has shifted a little to the north since the last advisory, so the new track forecast is a little north of the previous track. Key Messages: 1. Even though Ernesto is forecast to remain well offshore of the U.S. East Coast, swells generated by the hurricane will continue to affect the area through the early part of this week. Beach goers should be aware that there is a significant risk of life-threatening surf and rip currents, and should stay out of the water if advised by lifeguards. Surf and rip currents are also possible on the Bahamas, Bermuda, and Atlantic Canada during the next few days. 2. Ernesto could bring wind, wave, and rain impacts to portions of southeastern Newfoundland Monday night into Tuesday morning. Breaking waves could bring the possibility of coastal flooding, particularly along southwest-facing shorelines from Bunin east to Avalon regions. For additional impact specific information, please see statements issued by the Canadian Hurricane Centre. FORECAST POSITIONS AND MAX WINDS INIT 19/0300Z 38.5N 61.4W 70 KT 80 MPH 12H 19/1200Z 40.9N 59.3W 75 KT 85 MPH 24H 20/0000Z 44.3N 54.3W 65 KT 75 MPH 36H 20/1200Z 47.4N 46.6W 55 KT 65 MPH...POST-TROP/EXTRATROP 48H 21/0000Z 50.0N 35.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 60H 21/1200Z 52.5N 24.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 72H 22/0000Z...DISSIPATED $$ Forecaster Beven