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| #1094340 (Received by flhurricane at: 10:54 PM 05.Jun.2022) TCDAT1 Tropical Storm Alex Discussion Number 14 NWS National Hurricane Center Miami FL AL012022 1100 PM AST Sun Jun 05 2022 The satellite presentation of Alex has evolved from a more classic sheared tropical cyclone this morning to that of an extratropical transitioning cyclone. There are still some fragments of convection near the center, but most of the shower and thunderstorm activity is well removed from the center in a band around the eastern portion of the circulation. This change in structure is due to an approaching mid- to upper-level trough and associated dry air that has become entrained into the circulation. Air Force reconnaissance aircraft observations and data from NOAA buoy 41048 indicate that Alex is slightly stronger. Reports from a center drop from the aircraft showed that the pressure had fallen to around 984 mb, and the buoy reported a peak one-minute wind of 52 kt at 4 meters. Based on these data the initial intensity has been set at 60 kt. However, the cyclone may already be beginning to fill as the latest reconnaissance aircraft pass through the center reported that the pressure had risen 4 mb. Alex will be moving over cooler waters and into a higher shear environment during the next 12-24 hours, therefore weakening should commence very soon. Simulated satellite imagery from the GFS and ECMWF suggest the system will struggle to redevelop deep convection near the center and the system is now forecast to become post-tropical by 24 hours, if not sooner. The global model guidance now also indicates that the post-tropical cyclone will be absorbed along a frontal boundary as a new baroclinic low develops from a strong mid-latitude trough moving southeastward from Atlantic Canada in a day or two. As a result, the new NHC forecast calls for absorption within the new low within 48 hours. Alex is moving 060/24 kt. The cyclone should remain on a general east-northeastward motion during the next day or so, with the center passing north of Bermuda on Monday. The new forecast is again faster than the previous advisory and lies near a blend of the GFS and ECMWF models. KEY MESSAGES: 1. Alex is forecast to pass near or just north of Bermuda on Monday, and tropical storm conditions are expected on the island late tonight and Monday. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 32.5N 69.0W 60 KT 70 MPH 12H 06/1200Z 33.7N 65.3W 50 KT 60 MPH 24H 07/0000Z 35.3N 60.2W 45 KT 50 MPH...POST-TROP/EXTRATROP 36H 07/1200Z 37.4N 54.3W 45 KT 50 MPH...POST-TROP/EXTRATROP 48H 08/0000Z...ABSORBED BY EXTRATROPICAL LOW $$ Forecaster Brown |
