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| #1150278 (Received by flhurricane at: 7:45 AM 30.Aug.2023) TCDAT3 Hurricane Franklin Discussion Number 39 NWS National Hurricane Center Miami FL AL082023 500 AM AST Wed Aug 30 2023 Franklin has a large eye this morning since completing its eyewall replacement cycle yesterday. The estimated diameter from satellite data is about 50 n mi. With that said, there are some subtle signs that vertical wind shear over the system has begun to increase. The hurricane`s outflow has become restricted in the western side of the storm, related to the outflow of Idalia spreading quickly towards it. Intensity estimates have been gradually decreasing, and the initial intensity was lowered to 95 kt this advisory. This intensity lies roughly in between the higher TAFB and lower SAB subjective estimates, and is very close to the most recent ADT and D-MINT estimates provided by UW-CIMSS. Franklin appears to be accelerating ever so slightly to the northeast, with the motion of its large eye estimated at 040/11 kt. This motion is expected to continue today with a turn to the east-northeast in about 24-36 h. However, once again the guidance this cycle has trended much slower compared to the previous one. The ECMWF, which had been on the slow and south end of the guidance envelope for days now, related to it missing the mid-latitude trough capture, is no longer alone, with the latest GFS forecast substantially slower and also missing an initial trough capture. The track forecast has thus been slowed down again from the prior cycle, but since most of this track adjustment was in the along- and not across-track direction, it actually lies pretty much on top of the prior NHC track, just slower. This current forecast may need to be adjusted further in subsequent cycles, as suggested by the TVCA and HCCA consensus aids. Even though the center of Franklin is still forecast to pass to the northwest of Bermuda later today, the large area of tropical-storm-force winds associated with the hurricane to its southeast are expected to extend near or over the island, where a tropical storm warning remains in place. Intensity-wise, Franklin should gradually weaken early on, while shear remains fairly low, but then more quickly as northwesterly shear increases to between 20-30 kt from 24-48 h. Based on the latest forecast track, it may take a bit longer for Franklin to become an extratropical cyclone, and this is now delayed to day 4 in the latest NHC intensity forecast. This intensity forecast is in best agreement with the HCCA consensus aid. KEY MESSAGES: 1. Tropical storm conditions are expected on Bermuda this morning, when Franklin is forecast to make its closest approach to the island. 2. Life-threatening surf and rip currents are occurring along the east coast of the United States. These conditions are expected to continue during the next several days. FORECAST POSITIONS AND MAX WINDS INIT 30/0900Z 33.0N 68.2W 95 KT 110 MPH 12H 30/1800Z 34.0N 66.6W 95 KT 110 MPH 24H 31/0600Z 35.0N 63.7W 90 KT 105 MPH 36H 31/1800Z 35.8N 60.6W 80 KT 90 MPH 48H 01/0600Z 37.0N 57.0W 70 KT 80 MPH 60H 01/1800Z 38.0N 53.5W 65 KT 75 MPH 72H 02/0600Z 40.0N 49.5W 60 KT 70 MPH 96H 03/0600Z 44.1N 44.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 120H 04/0600Z 49.0N 43.0W 50 KT 60 MPH...POST-TROP/EXTRATROP $$ Forecaster Papin |
