ZCZC MIATCDAT3 ALL TTAA00 KNHC DDHHMM Hurricane Lee Discussion Number 41 NWS National Hurricane Center Miami FL AL132023 1100 AM AST Fri Sep 15 2023 Lee remains a very large hurricane over the western Atlantic. The strongest winds extend out to roughly 70 miles from the center, hurricane-force winds around 100 miles and tropical-storm-force winds more than 300 miles. Data from both the NOAA and Air Force Hurricane Hunters indicate that the core winds have decreased slightly, and a blend of the latest flight-level and SFMR winds support an intensity of 70 kt. Satellite images indicate that the hurricane is asymmetric with most of the convection on the north side. The hurricane has been wobbling around, but it has generally been moving north-northeastward at 16 kt during the past 12-18 hours on the western side of a subtropical ridge. A northward to north-northeastward motion at about the same forward speed is expected until Lee makes landfall in Atlantic Canada in 24 to 36 hours. After landfall, Lee is forecast to accelerate to the northeast when it moves in the flow on the east side of an approaching trough. The models are tightly clustered, and no significant changes were made to the previous NHC track forecast. Southerly vertical wind shear and dry air are eroding deep convection on the hurricane's south side. These environmental conditions are expected to persist while Lee moves over sharply cooler waters during the next day or so. Therefore, steady weakening is forecast and Lee will likely become extratropical around the time it makes landfall. The NHC intensity forecast is a little lower than the previous one, and fairly close to the GFS model prediction. Lee is expected to remain a large and dangerous system over the next couple of days. KEY MESSAGES: 1. Hurricane conditions are possible across portions southern New Brunswick, and much of Nova Scotia on Saturday within the Hurricane Watch area. Tropical storm conditions and coastal flooding are expected to begin in southern New England within the Tropical Storm Warning area this afternoon, and spread northward along the coast of New England and over portions of Atlantic Canada through Saturday. These conditions are likely to lead to downed trees and potential power outages. 2. Heavy rainfall from Lee could produce localized urban and small stream flooding in eastern Maine into portions of New Brunswick and Nova Scotia from tonight into Saturday night. 3. Tropical storm conditions and high surf will continue to impact Bermuda during the next few hours. FORECAST POSITIONS AND MAX WINDS INIT 15/1500Z 36.0N 66.9W 70 KT 80 MPH 12H 16/0000Z 38.5N 66.4W 70 KT 80 MPH 24H 16/1200Z 41.8N 66.2W 65 KT 75 MPH 36H 17/0000Z 45.1N 65.7W 55 KT 65 MPH...POST-TROP/EXTRATROP 48H 17/1200Z 47.8N 62.8W 45 KT 50 MPH...POST-TROP/EXTRATROP 60H 18/0000Z 50.8N 57.8W 40 KT 45 MPH...POST-TROP/EXTRATROP 72H 18/1200Z 53.4N 51.3W 35 KT 40 MPH...POST-TROP/EXTRATROP 96H 19/1200Z...DISSIPATED $$ Forecaster Cangialosi/A Reinhart NNNN