000 WTNT44 KNHC 180847 TCDAT4 Hurricane Humberto Discussion Number 23 NWS National Hurricane Center Miami FL AL092019 500 AM AST Wed Sep 18 2019 Humberto's satellite presentation continues to be outstanding with a large ragged eye and surrounded by deep convection. The eye of the hurricane is very near NOAA Buoy 41048 and most likely will passing over it by the time this advisory is being released. The pressure from the buoy has been dropping fast and is now at 961 mb and the sustained winds have reached 58 kt with gusts to 78 kt. Based on satellite appearance and continuity, the initial intensity is kept at 100 kt. Another Hurricane Hunter aircraft will check the cyclone in a few hours. Some fluctuations in strength due to a potential eyewall replacement are possible during the next 12 to 24 hours or so. After that time very strong southwesterly wind shear should impact the hurricane resulting in weakening. In 72 hours or earlier, the global models show the system merging with a frontal zone, so the NHC forecast calls for extratropical transition by that time. The official intensity forecast follows the corrected consensus HCCA and is not very different from the previous one. Humberto is accelerating, and satellite fixes yield an initial motion toward the east-northeast or 065 degrees at 14 kt. Humberto is located at the base of a strong mid-to upper-level trough, and the hurricane will likely interact with this amplifying trough. This should force Humberto to turn toward the northeast and north- northeast at a faster forward speed in 24-36 hours. Later in the forecast period, the track guidance indicates that Humberto will turn back toward the east-northeast while becoming embedded within the mid-latitude westerlies. The NHC track forecast is very similar to the previous one and is in the middle of the guidance envelope. Key Messages: 1. Hurricane conditions are expected in Bermuda tonight and Thursday morning, with tropical-storm-force winds expected to begin later today. Residents there should follow advice given by local officials. 2. Storm surge and dangerous breaking waves could cause coastal flooding tonight and Thursday along the southern coast of Bermuda. 3. Swells will continue to affect the northwestern Bahamas and the southeastern coast of the United States from east-central Florida to North Carolina during the next couple of days, creating life- threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 18/0900Z 31.7N 69.6W 100 KT 115 MPH 12H 18/1800Z 32.7N 67.2W 105 KT 120 MPH 24H 19/0600Z 34.8N 63.5W 100 KT 115 MPH 36H 19/1800Z 37.5N 61.0W 85 KT 100 MPH 48H 20/0600Z 40.0N 59.5W 65 KT 75 MPH 72H 21/0600Z 43.0N 53.9W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 22/0600Z 45.5N 38.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 23/0600Z 52.1N 23.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Avila