000 WTNT44 KNHC 200249 TCDAT4 Post-Tropical Cyclone Humberto Discussion Number 30 NWS National Hurricane Center Miami FL AL092019 1100 PM AST Thu Sep 19 2019 Satellite images show what little deep convection remains has been displaced well to the north of the center of the cyclone, and it can no longer be classified via the Dvorak technique. Moreover, cold air stratocumulus clouds over the western and southern portions of the circulation are indicative of cold air advection that is characteristic of an extratropical cyclone. Therefore, Humberto is now post-tropical and this will be the last advisory issued by the National Hurricane Center on this system. It is estimated that the cyclone still has hurricane-force winds and based on continuity from previous estimates with a gradual weakening rate, the current intensity is set at 85 kt. Continued gradual weakening is likely, and after 48 hours the system is expected to merge with another extratropical low over the north Atlantic. The cyclone has turned north-northeastward along the eastern side of a deep layer cyclonic circulation, with a current motion estimate of 030/17 kt. A turn toward the east-northeast is expected in a day or so as the system moves within the mid-latitude westerlies until dissipation. Key Messages: 1. Large swells will continue to affect Bermuda, the northwestern Bahamas, and the east coast of the United States from east-central Florida to the Mid-Atlantic States during the next couple of days. These swells could create life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 20/0300Z 40.0N 58.0W 85 KT 100 MPH...POST-TROP/EXTRATROP 12H 20/1200Z 41.8N 56.8W 70 KT 80 MPH...POST-TROP/EXTRATROP 24H 21/0000Z 44.0N 54.0W 60 KT 70 MPH...POST-TROP/EXTRATROP 36H 21/1200Z 45.5N 48.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 48H 22/0000Z 46.5N 40.5W 50 KT 60 MPH...POST-TROP/EXTRATROP 72H 23/0000Z...DISSIPATED $$ Forecaster Pasch