ZCZC MIATCDAT3 ALL TTAA00 KNHC DDHHMM Hurricane Lee Discussion Number 31 NWS National Hurricane Center Miami FL AL132023 1100 PM AST Tue Sep 12 2023 Geostationary satellite images show that Lee has a large eye about 40 n mi in diameter surrounded by very cold-topped central convection. There are numerous convective banding features, especially over the northern portion of the circulation. The cirrus-level outflow pattern is fairly symmetric at this time, suggesting that the vertical wind shear over the system is still low. The intensity estimate is held at 100 kt for this advisory, which is a blend of subjective and objective satellite estimates from TAFB, SAB, and UW/CIMSS. The objective intensity estimates are generally a little higher than the subjective values. Lee continues to move on a generally northwestward heading, with a motion estimate of 320/6 kt, on the southwestern side of a mid-level anticyclone. Over the next couple of days, a 500-mb trough moving through the eastern United States should induce a northward turn with some increase in forward speed. Even though the predicted track has the center of the hurricane passing well to the west of Bermuda, Lee's very large wind field should result in tropical storm conditions spreading over the island by late Wednesday or early Thursday. In the 3 to 4 day time frame, the model guidance suggests just a slight leftward bend in the track while Lee interacts with the trough. There has been little change to the NHC forecast track, which remains close to the corrected and simple model consensus predictions. After 96 hours, Lee should turn northeastward and east-northeastward in the mid-latitude westerlies. Gradual weakening is anticipated during the next few days days while Lee moves over cooler waters and encounters high vertical wind shear. However the system is likely to remain a large and dangerous hurricane while it approaches the coast. If Lee moves faster than forecast over the colder waters north of the Gulf Stream, it will likely retain more of its strength when it reaches land. Around 96 hours, simulated satellite imagery from the global models show the appearance of an extratropical cyclone with decreased convection and an asymmetric cloud pattern. It should again be noted that the 34- and 50-kt wind speed probabilities beyond 36 hours in the text product and graphics are likely underestimating the risk of those winds occurring. This is because the forecast wind field of Lee is considerably larger than average compared to the wind field used to derive the wind speed probability product. KEY MESSAGES: 1. Dangerous surf and life-threatening rip currents will affect portions of the northern Leeward Islands, the Virgin Islands, Puerto Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas, Bermuda, and most of the U.S East Coast through much of the week. 2. Tropical storm conditions, heavy rainfall, and high surf are expected to impact Bermuda beginning Wednesday night or early Thursday, and a Tropical Storm Warning has been issued for the island. 3. It remains too soon to know what level of additional impacts Lee might have along the northeastern U.S. coast and Atlantic Canada late this week and this weekend. However, since wind and rainfall hazards will extend well away from the center as Lee grows in size, users should continue to monitor updates to Lee's forecast during the next several days. FORECAST POSITIONS AND MAX WINDS INIT 13/0300Z 25.3N 66.7W 100 KT 115 MPH 12H 13/1200Z 26.1N 67.2W 100 KT 115 MPH 24H 14/0000Z 27.7N 67.8W 95 KT 110 MPH 36H 14/1200Z 29.7N 68.2W 90 KT 105 MPH 48H 15/0000Z 32.1N 67.9W 80 KT 90 MPH 60H 15/1200Z 35.0N 67.1W 75 KT 85 MPH 72H 16/0000Z 38.0N 66.6W 75 KT 85 MPH 96H 17/0000Z 44.0N 66.4W 60 KT 70 MPH...POST-TROP/EXTRATROP 120H 18/0000Z 48.5N 62.0W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Pasch NNNN