| No change to the 5pm AST Monday info in the subject line. They do talk about the large eyewall and about from an earlier satellite pass it was closed. At the end of the 5 day forecast period the storm is forecast to be post-tropical. That just means wider impacts with a broader wind field. The 5 day forecast track is almost to Canada, so over 5 days the storm is really going to start picking up speed. They mention the Saildrones Cypress posted about, with some in, or near, the path upcoming: https://canetalk.com/2023/09/1694179868.shtml Hurricane Lee Discussion Number 27 NWS National Hurricane Center Miami FL AL132023 1100 PM AST Mon Sep 11 2023 This evening, Lee appears to be in the final stages of completing another eyewall replacement cycle (ERC). A GPM microwave pass at 2201 UTC showed that the outer eyewall remains closed and, while it remains quite large, continues to contract slowly as the inner eyewall decays within. The initial intensity is held at 100 kt this advisory, blending the subjective and objective intensity estimates this evening. Another Air Force Reserve Reconnaissance mission is scheduled to investigate the storm overnight, and several saildrones along Lee's path are also likely to provide additional in-situ observations in the hurricane over the next day or so. Lee continues to move slowly west-northwestward, with the motion estimated at 295/6 kt. Lee is expected to continue moving slowly west-northwest or northwest over the next 24-36 h while mid-level ridging remains in place centered northwest of the hurricane. However, the ridge should then become eroded and shift eastward as a mid- to upper-level trough swings into the northeastern United States. This pattern change should result in Lee turning northward and gradually accelerating. The biggest spread in the track guidance solutions remains in the along-track direction, with the GFS on the faster end, and ECMWF on the slower end. The NHC track forecast continues to favor a blend of the simple and corrected consensus aids, and is very close to the previous forecast track through 72 h, and is just a touch east of the prior track thereafter. On this track, Lee is likely to pass near, but west of, Bermuda late Thursday and Friday and then be situated offshore of the mid-Atlantic states and New England late Friday and Saturday. With the pending completion of Lee's ERC, expected over the next 6-12 hours, the NHC intensity forecast continues to show some modest re-intensification. This seems reasonable given that sea surface temperatures (SSTs) observed by a saildrone in Lee's south outer eyewall are still around 29 C. After the next day or so, however, coupled atmospheric-ocean models suggest the large wind field of Lee will begin to upwell cooler SSTs, and Lee is still forecast to move over a cool SST wake left behind by Hurricanes Idalia and Franklin later this week. In addition, the approaching mid-latitude trough should also result in an increase in shear, and dry air entrainment, which should result in more steady weakening later this week and over the weekend. This trough interaction will also ultimately lead to Lee transitioning to an extratropical cyclone by the end of the forecast period as it crosses the north wall of the Gulf Stream. The NHC intensity forecast is a bit lower than the prior cycle after 72 h but remains close to the consensus intensity aids. Although Lee is expected to weaken later in the week, it is still expected to significantly increase in size and hazards will extend well away from the storm center by the end of the forecast period. 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. Lee could bring strong winds, rainfall, and high surf impacts to Bermuda later this week. Interests there should continue to monitor updates to the forecast of Lee during the next several days. 3. It remains too soon to know what level of additional impacts Lee might have along the Northeast U.S. coast and Atlantic Canada late this week and this weekend. However, because wind and rainfall hazards will likely 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 12/0300Z 23.9N 64.8W 100 KT 115 MPH 12H 12/1200Z 24.4N 65.6W 105 KT 120 MPH 24H 13/0000Z 25.0N 66.5W 105 KT 120 MPH 36H 13/1200Z 26.1N 67.2W 100 KT 115 MPH 48H 14/0000Z 27.5N 67.6W 95 KT 110 MPH 60H 14/1200Z 29.4N 67.9W 90 KT 105 MPH 72H 15/0000Z 31.6N 67.8W 80 KT 90 MPH 96H 16/0000Z 37.6N 66.4W 70 KT 80 MPH 120H 17/0000Z 43.0N 66.0W 60 KT 70 MPH...POST-TROP/EXTRATROP $$ Forecaster Papin |