000 WTNT42 KNHC 062037 TCDAT2 Hurricane Kirk Discussion Number 30 NWS National Hurricane Center Miami FL AL122024 500 PM AST Sun Oct 06 2024 Satellite imagery suggests that Kirk has begun the process of extratropical transition. Most of the convection is located on the north side of the low-level center due to strong south-southwesterly wind shear. Subjective Dvorak estimates from SAB and TAFB range from 65-75 kt, while the latest objective intensity estimates from UW-CIMSS range from 65-80 kt. The intensity has been lowered to 75 kt for this advisory. ASCAT data from earlier this morning necessitated an increase in the initial wind radii, showing that Kirk is a very large hurricane. There have been no significant changes to the track reasoning. A narrow mid- to upper-level ridge east of Kirk will weaken over the next 24-36 h, allowing Kirk to turn east-northeastward or eastward within the zonal mid-latitude westerly flow. The new NHC track forecast lies nearly on top of the previous NHC track, although the new track is a bit slower. This track is relatively close to the TVCA and a bit slower than the HCCA corrected consensus guidance. The NHC forecast shows Kirk passing north of the Azores Monday night and Tuesday as an extratropical cyclone, and should reach western Europe late Wednesday, where it could bring gale force winds. Kirk is forecast to continue to gradually weaken as it reaches cooler waters by tonight. Additionally, the southwesterly vertical wind shear is forecast to increase significantly over the system by early Monday morning. Global models show the development of frontal features on Monday, and extratropical transition has been moved up to 24 h in the latest official forecast. Despite gradual weakening as Kirk becomes post-tropical, the cyclone is expected to remain a large and powerful cyclone until it reaches the coast of western Europe. Therefore, the system will continue to spread very large swells across a large portion of the North Atlantic Ocean for a few more days. The latest NHC intensity forecast is at the high end of the guidance during the extratropical portion of the forecast, in best agreement with the GFS and ECMWF global models. By early Thursday, the cyclone will become elongated over western Europe, and the latest NHC forecast shows dissipation in 96 h. FORECAST POSITIONS AND MAX WINDS INIT 06/2100Z 37.0N 46.2W 75 KT 85 MPH 12H 07/0600Z 39.4N 42.9W 70 KT 80 MPH 24H 07/1800Z 42.1N 37.2W 65 KT 75 MPH...POST-TROP/EXTRATROP 36H 08/0600Z 43.3N 30.2W 60 KT 70 MPH...POST-TROP/EXTRATROP 48H 08/1800Z 43.6N 21.6W 55 KT 65 MPH...POST-TROP/EXTRATROP 60H 09/0600Z 44.7N 11.7W 50 KT 60 MPH...POST-TROP/EXTRATROP 72H 09/1800Z 47.1N 2.6W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 10/1800Z...DISSIPATED $$ Forecaster Hagen