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| #981423 (Received by flhurricane at: 10:54 PM 06.Sep.2019) TCDAT5 Hurricane Dorian Discussion Number 55 NWS National Hurricane Center Miami FL AL052019 1100 PM EDT Fri Sep 06 2019 During the past couple of hours Dorian`s eye has become no longer apparent in conventional satellite imagery. Microwave data shows an eye-like feature just to the south of the convection, and also indicates that the hurricane is becoming asymmetric. The lack of symmetry is the first indication or hint that Dorian is slowly beginning to acquire some extratropical characteristics. The rain shield is now placed to the northwest of the center, and the wind field is expanding in the southern semicircle. Dvorak numbers are either steady or have decreased slightly, and consequently the initial intensity is kept at 80 kt in this advisory. The hurricane is rapidly reaching cooler waters and guidance shows an area of significantly strong shear along the forecast path of Dorian. Given these conditions, the NHC forecast calls for gradual weakening, but Dorian is still expected to make landfall in Nova Scotia with hurricane intensity late Saturday. Dorian is forecast to complete its transition to extratropical once it crosses Nova Scotia. The hurricane is racing northeastward or 045 degrees at 22 kt. Since Dorian is already embedded within a fast southwesterly flow ahead of a mid-latitude trough, the current northeast heading should continue until dissipation occurs in about 3 days, if not sooner. The track guidance is in remarkably good agreement, and the NHC forecast is in the middle of the guidance envelope, increasing the confidence in the track forecast. Key Messages: 1. Regardless of whether it is a hurricane or a post-tropical cyclone, Dorian is expected to have a significant impact in portions of eastern Canada. Dangerous storm surge impacts are likely in portions of the Gulf of St. Lawrence, southwestern Newfoundland and eastern Nova Scotia this weekend. Hurricane-force winds are also likely in Nova Scotia, Prince Edward Island and possibly Newfoundland Saturday and Sunday. Refer to information from the Canadian Hurricane Centre for more information on these hazards. FORECAST POSITIONS AND MAX WINDS INIT 07/0300Z 38.3N 70.2W 80 KT 90 MPH 12H 07/1200Z 40.8N 66.9W 75 KT 85 MPH 24H 08/0000Z 45.0N 63.0W 70 KT 80 MPH...INLAND 36H 08/1200Z 49.0N 59.5W 55 KT 65 MPH...POST-TROP/EXTRATROP 48H 09/0000Z 52.0N 55.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 72H 10/0000Z 56.0N 41.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 11/0000Z...DISSIPATED $$ Forecaster Avila |
