ZCZC MIATCDAT3 ALL TTAA00 KNHC DDHHMM Hurricane Lee Discussion Number 12 NWS National Hurricane Center Miami FL AL132023 500 AM AST Fri Sep 08 2023 Lee remains an extremely powerful category 5 hurricane. Satellite images indicate that Lee has a symmetric inner core with a 10 n mi circular and clear eye and no indications of concentric eyewalls forming yet. Although the hurricane is incredibly powerful, its wind field is not particularly large with its tropical-storm-force winds extending roughly 100 n mi from the center. The Air Force Hurricane Hunters investigated Lee earlier this morning and found that the pressure has fallen to about 926 mb, based on dropsonde data. In addition, the maximum 700-mb flight-level wind reported was 153 kt and maximum surface SFMR wind was 158 kt, but this estimate could be inflated. Blending these measurements, the initial wind speed is nudged upward to 145 kt. Both the NOAA and Air Force Hurricane Hunters will further investigate Lee in a couple of hours. Since Lee is expected to remain in favorable atmospheric conditions while moving over even warmer waters during the next couple of days, it seems likely that the hurricane will at least maintain its intensity or become a little stronger during that time. The dominant factor for Lee's short term intensity will be internal dynamics, like eyewall replacement cycles. These conditions will often cause fluctuations in the hurricane's strength, which are challenging to forecast. There likely will be some weakening beyond a few days when Lee moves over somewhat cooler waters and into an environment of slightly higher shear. Regardless of the details, Lee is expected to remain a powerful hurricane during the next several days. The major hurricane has been on a steady west-northwest path during the past couple of days as it has been steered by the flow on the south side of a subtropical ridge over the central Atlantic. A continued west-northwest motion is expected, but at a progressively slower pace during the forecast period as the ridge to the north of the system weakens. The models are in fairly good agreement, and little change was made to the previous NHC track forecast. Lee is expected to increase in size and become more symmetric over the weekend and early next week as the hurricane slows down. Recent wave altimeter data showed peak significant wave heights between 45 and 50 feet near the center. Dangerously high seas are expected to continue near the core of the hurricane, and large swells will spread well away from the system through the forecast period. KEY MESSAGES: 1. Lee is a dangerous category 5 hurricane, and further strengthening is possible. Lee's core is expected to move well north of the northern Leeward Islands, the Virgin Islands, and Puerto Rico this weekend and early next week. 2. Dangerous surf and life-threatening rip currents are likely in the northern Leeward Islands beginning later today. These conditions will spread westward and northward, affecting Puerto Rico, Hispaniola, the Turks and Caicos, the Bahamas, and Bermuda through the weekend. 3. It is way too soon to know what level of impacts, if any, Lee might have along the U.S. East Coast, Atlantic Canada, or Bermuda late next week, particularly since the hurricane is expected to slow down considerably over the southwestern Atlantic. Regardless, dangerous surf and rip currents are expected along most of the U.S. East Coast beginning Sunday. Continue to monitor updates to Lee's forecast during the next several days. FORECAST POSITIONS AND MAX WINDS INIT 08/0900Z 17.8N 53.5W 145 KT 165 MPH 12H 08/1800Z 18.6N 55.1W 155 KT 180 MPH 24H 09/0600Z 19.6N 57.1W 150 KT 175 MPH 36H 09/1800Z 20.5N 58.8W 145 KT 165 MPH 48H 10/0600Z 21.2N 60.2W 145 KT 165 MPH 60H 10/1800Z 21.9N 61.5W 140 KT 160 MPH 72H 11/0600Z 22.4N 62.7W 135 KT 155 MPH 96H 12/0600Z 23.3N 65.1W 130 KT 150 MPH 120H 13/0600Z 24.4N 67.1W 120 KT 140 MPH $$ Forecaster Cangialosi NNNN