ZCZC MIATCDAT3 ALL TTAA00 KNHC DDHHMM Hurricane Lee Discussion Number 17 NWS National Hurricane Center Miami FL AL132023 1100 AM AST Sat Sep 09 2023 Satellite imagery shows that deep convection continues to pulse near the center of Lee. Recent reports from reconnaissance aircraft and an earlier SSMIS microwave image indicates that Lee has a small (5 to 10 n-mi-wide) eye that is obscured by the higher convective cloud tops. The NOAA P-3 Hurricane Hunter aircraft penetrated the eye around 1013 UTC this morning and found that the pressure was down a few millibars. The NOAA aircraft measured peak SFMR surface winds of 100 kt, and 700-mb flight-level winds of 103 kt. An Air Force Reserve reconnaissance aircraft remains in the storm environment, but due to safety concerns was not able to penetrate the northeastern eyewall on its first pass through the storm due to very strong convection and mesovortices orbiting the small eye. A recent center drop from the Air Force plane suggest that the minimum pressure is around 957 mb. Drops from both aircraft and Doppler radar data from the earlier NOAA aircraft indicate that there is some southwest to northeast tilt to the vortex. Based on the aircraft data, the initial intensity remains 100 kt for this advisory. There is still some question as to how conducive the upper-level environment will be during the next few days. The GFS and regional hurricane models indicate that the shear that has been affecting Lee will decrease today, and that the upper-level wind pattern will become much more favorable for restrengthening. Meanwhile, the ECMWF and UKMET models depict a less favorable environment, with a continuation of at least some moderate shear. The NHC forecast follows the scenario that there will be at least some relaxation of the shear and it calls for gradual restrengthening during the next two to three days. The official wind speed forecast is not as high as some of the dynamical model guidance, but is a blend of the HFIP corrected consensus model and the IVCN multi-model consensus. Lee is still moving west-northwestward or 300/10 kt. A mid-level ridge located over the central Atlantic is forecast to build west-southwestward during the next few days. This should keep Lee on a general west-northwestward heading, but the building ridge is expected to impede Lee's progress, and a much slower forward speed is anticipated over the next several days. By Wednesday, Lee should begin to turn northwestward, and then north-northwestward as a mid-latitude trough moves into the Great Lakes region and eastern United States. While the cross track spread in the guidance remains fairly low, there is significant long track (forward speed) spread in the models. The GFS and ECMWF depict similar overall tracks, but the cross-track spread between those two typically reliable models is more than 150 n mi by day 3. The NHC forecast splits these speed differences and lies near the various consensus aids. KEY MESSAGES: 1. 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 affecting portions of the northern Leeward Islands. These conditions are spreading westward and northward and will begin affecting Puerto Rico, Hispaniola, the Turks and Caicos, the Bahamas, and Bermuda later today and Sunday. 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 and Monday. Continue to monitor updates to Lee's forecast during the next several days. FORECAST POSITIONS AND MAX WINDS INIT 09/1500Z 20.3N 58.2W 100 KT 115 MPH 12H 10/0000Z 21.0N 59.3W 100 KT 115 MPH 24H 10/1200Z 21.7N 60.6W 105 KT 120 MPH 36H 11/0000Z 22.4N 61.9W 110 KT 125 MPH 48H 11/1200Z 22.9N 63.1W 115 KT 130 MPH 60H 12/0000Z 23.3N 64.2W 120 KT 140 MPH 72H 12/1200Z 23.6N 65.3W 120 KT 140 MPH 96H 13/1200Z 24.4N 67.0W 110 KT 125 MPH 120H 14/1200Z 26.8N 67.8W 105 KT 120 MPH $$ Forecaster Brown NNNN