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| #1106157 (Received by flhurricane at: 10:57 AM 07.Sep.2022) TCDAT1 Hurricane Earl Discussion Number 19 NWS National Hurricane Center Miami FL AL062022 1100 AM AST Wed Sep 07 2022 While it is evident that westerly vertical wind shear continues to affect the overall satellite presentation of Earl, useful data from the NOAA-P3 Hurricane Hunter aircraft indicates that the hurricane is holding its own and has even strengthened a bit. Part of this resilience could be due to the fact that the low and mid-level centers of Earl are now vertically stacked with the wind field relatively symmetric per the most recent set of Tail Doppler Radar from the aircraft. However, the westerly shear is still affecting the inner-core structure of the system, with its large 40 n mi wide eye open in the southern semicircle. The highest flight- level winds from this morning`s mission was 82 kt at 700 mb with SFMR at 75 kt. The initial intensity was increased to 75 kt at the 8am intermediate advisory and remains this value for this advisory. Fixes from this morning indicate that Earl has been moving just east of due north, with the motion estimated at 005/6 kt. The hurricane is caught in between a mid-level ridge now centered to its southeast, with a positively-tilted upper-level trough located to the northwest. This synoptic setup should enable Earl to begin recurving north-northeastward and then northeastward as it accelerates over the next 24-48 hours. The track guidance remains tightly clustered during the early portion of the forecast, with the GFS and ECMWF tracks now nearly identical during this period. The official track forecast was only adjusted a touch east of the prior one during this period. However, as noted previously, there is increasing model support that the upper-level trough will ultimately phase with Earl after 72 hours, resulting in the cyclone slowing down significantly and potentially turning more northward in days 4-5. The official track forecast during this period now shows a bit more of a northward bend and further slowdown compared to the prior track, favoring a blend of the latest GFS and ECMWF forecast. The persistent deep-layer westerly vertical wind shear that has been impacting Earl the last several days is finally forecast to subside later today, dropping below 10 kt in 24 hours. This decreasing shear, in combination with very warm sea-surface temperatures, favorable positioning in the right-entrance region of an upper-level jet streak, and significant acceleration in the storm motion, is likely to result in substantial strengthening of the surface wind field and the latest NHC intensity forecast now shows a peak at 115 kt in 60-h, in good general agreement with the latest HCCA, yet still under the LGEM intensity aid. After that, a significant trough interaction is likely to rapidly increase baroclinicity, with Earl forecast to become an extratropical-low as it phases with the upper-level trough between days 3-4 in the forecast period. KEY MESSAGES: 1. Although Earl`s center is forecast to pass southeast of Bermuda, the wind field is expected to grow, with tropical-storm-force winds forecast to spread across the island beginning Thursday afternoon and continuing through Friday morning. 2. Swells generated by Earl are expected to reach Bermuda by tonight and the U.S. East Coast shortly thereafter. 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 07/1500Z 25.7N 65.7W 75 KT 85 MPH 12H 08/0000Z 26.8N 65.6W 80 KT 90 MPH 24H 08/1200Z 28.5N 65.2W 90 KT 105 MPH 36H 09/0000Z 30.4N 64.1W 100 KT 115 MPH 48H 09/1200Z 33.0N 61.5W 110 KT 125 MPH 60H 10/0000Z 36.4N 57.3W 115 KT 130 MPH 72H 10/1200Z 40.1N 53.1W 100 KT 115 MPH 96H 11/1200Z 45.0N 49.0W 60 KT 70 MPH...POST-TROP/EXTRATROP 120H 12/1200Z 47.0N 47.9W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Papin |
