724 WTNT41 KNHC 090847 TCDAT1 Hurricane Earl Discussion Number 26 NWS National Hurricane Center Miami FL AL062022 500 AM AST Fri Sep 09 2022 Radar data from Bermuda and conventional satellite images show that Earl's structure has improved a bit overnight with the eye becoming better defined and the overall cloud envelope looking more symmetric. An Air Force Reserve Hurricane Hunter aircraft measured a peak 700-mb flight-level wind of 97 kt and SFMR winds as high as 77 kt, with the central pressure down slightly to 963 mb. Based on the typical reduction of the flight-level winds, and accounting for undersampling of the surface winds, Earl's initial intensity is raised back to 85 kt. Reconnaissance and scatterometer data also indicate that Earl's wind field has continued to expand. Earl is accelerating toward the north-northeast (030 degrees at 15 kt) ahead of a shortwave trough approaching from the west near the New England coast. The hurricane is forecast to turn northeastward today and continue accelerating to speeds of 25-30 kt within 24 hours. After that time, however, Earl will merge with the aforementioned trough, slowing down considerably to speeds of around 5 kt to the southeast of Newfoundland in 60-72 hours. By days 4 and 5, the system should then move a little bit faster toward the east, embedded within the mid-latitude westerlies. The track guidance is in generally good agreement for much of the 5-day forecast period, and no significant changes were made to the updated NHC track forecast. Earl will remain over warm waters for another 24 hours or so, and the deep-layer shear should be low to moderate during the next 6 to 12 hours. As a result, some additional strengthening is anticipated through tonight, and the NHC intensity forecast is near the IVCN consensus during that period. A few models, including SHIPS, LGEM, and HCCA, still bring Earl to major hurricane strength in 24 hours, but given that the cyclone will be starting to undergo extratropical transition by then, that scenario is becoming increasingly unlikely (although not impossible). Global model fields indicate that Earl should complete the transition to a powerful extratropical low by 36 hours and then gradually weaken through the remainder of the forecast period. During the extratropical phase, the NHC intensity forecast is closest to the GFS solution. KEY MESSAGES: 1. Tropical storm conditions are expected to diminish on Bermuda later this morning. 2. Swells generated by Earl are affecting Bermuda and the U.S. East Coast and are expected to reach Nova Scotia and Newfoundland tonight and on Saturday. These swells are likely to cause life-threatening surf and rip current conditions through the weekend. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 09/0900Z 32.7N 62.4W 85 KT 100 MPH 12H 09/1800Z 35.0N 59.8W 90 KT 105 MPH 24H 10/0600Z 39.2N 55.5W 95 KT 110 MPH 36H 10/1800Z 42.7N 52.5W 80 KT 90 MPH...POST-TROP/EXTRATROP 48H 11/0600Z 44.1N 51.0W 60 KT 70 MPH...POST-TROP/EXTRATROP 60H 11/1800Z 44.9N 50.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 72H 12/0600Z 45.5N 49.4W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 13/0600Z 45.4N 45.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 120H 14/0600Z 46.0N 40.2W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ Forecaster Berg