000 WTNT45 KNHC 060236 TCDAT5 Hurricane Danielle Discussion Number 20 NWS National Hurricane Center Miami FL AL052022 300 AM GMT Tue Sep 06 2022 Danielle's cloud pattern has deteriorated during the past several hours. The outer curved band cloud tops have warmed while becoming ragged, and the eye temperature has cooled while becoming partially obscured. A recent microwave image, however, indicated very little vertical tilt while maintaining a symmetric structure. A blend of the subjective satellite intensity estimates from TAFB and SAB along with the AI-enhanced Advanced Dvorak Technique (AiDT) from UW-CIMSS yields an initial intensity of 70 kt for this advisory. Danielle's wind radii profile was expanded a bit in the east semicircle based on recent METOP-B/C scatterometer data. The cyclone should gradually spin down as it traverses cooler SSTs of less than 22C by mid-period. The GFS/ECMWF/UKMET continue to be in agreement that Danielle will complete its extratropical transition on Thursday, although the vertical thermal structure shows the system maintaining a warm core above 600 mb. Over the weekend, Global model simulated IR imagery, and the Cyclone Phase Analysis show Danielle merging with a baroclinic system approaching from the west and developing a warm seclusion structure (shallow warm core with a cold core upper troposphere). Although not explicitly indicated in the official forecast, Danielle could maintain its intensity during this evolution is due to dynamic forcing/favorable jet finger support while it tracks cyclonically over the central-north Atlantic. The NHC intensity forecast resembles the IVCN intensity consensus which has performed well so far on the system. Danielle should still move generally northeastward in the deep-layer mid-latitude steering flow through the afternoon hours. Danielle is forecast to turn east-northeast on Wednesday while accelerating. Toward the end of the week, as mentioned above, the cyclone is expected to interact with a baroclinic system, while rotating cyclonically north of the westerlies, then turn toward the southeast. The only significant change in the official forecast track is the implementation of the cyclonic turn around day 3-4, which is based on the majority of the global models. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 41.6N 42.6W 70 KT 80 MPH 12H 06/1200Z 42.2N 41.6W 65 KT 75 MPH 24H 07/0000Z 42.8N 39.5W 65 KT 75 MPH 36H 07/1200Z 43.9N 36.9W 65 KT 75 MPH 48H 08/0000Z 45.5N 34.1W 60 KT 70 MPH 60H 08/1200Z 47.4N 31.6W 55 KT 65 MPH...POST-TROP/EXTRATROP 72H 09/0000Z 49.2N 30.1W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 10/0000Z 49.8N 31.6W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 11/0000Z 46.8N 26.1W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Roberts