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| #1106121 (Received by flhurricane at: 4:57 AM 07.Sep.2022) TCDAT1 Hurricane Earl Discussion Number 18 NWS National Hurricane Center Miami FL AL062022 500 AM AST Wed Sep 07 2022 Strong westerly shear (analyzed to be around 30 kt) continues to affect Earl, with the hurricane exhibiting an asymmetric convective structure in infrared satellite imagery. A recent Air Force Reserve Hurricane Hunter aircraft reported that the central pressure has fallen to 981 mb, however there`s been no apparent change in the maximum winds and the eyewall is open to the south and southeast. The plane measured a peak 700-mb flight-level wind of 78 kt and SFMR winds as high as 71 kt; therefore the maximum sustained winds are still estimated to be 70 kt. Earl has been moving slowly just west of due north, or 355/5 kt, while sandwiched between a mid-level ridge over the central Atlantic and high pressure over Florida. A trough over the eastern United States is expected to move offshore during the next couple of days, causing Earl to turn northeastward and accelerate through day 3. The track guidance is tightly clustered during the first 3 days of the forecast, although many of the models have trended a little slower during the northeastward turn. No cross-track adjustments to the NHC forecast were needed during that period. There has been a marked shift and increase in spread among the track models on days 4 and 5, however, with the GFS, ECMWF, and COAMPS-TC showing Earl merging with a deep-layer low and turning northward or northwestward toward Newfoundland as an extratropical low. For now, the updated NHC forecast shows Earl slowing down considerably to the southeast of Newfoundland on days 4 and 5. GFS- and ECMWF-based SHIPS guidance show the strong shear currently affecting Earl decreasing to moderate levels in about 12 hours, and even to low levels in about 36 hours. Combined with very warm waters and a possible positive trough interaction during the next 24 hours, Earl is forecast to strengthen and is likely to become a major hurricane in the next 36 to 48 hours while passing to the southeast of Bermuda. Weakening is expected to begin after day 3 due to colder waters and another increase in shear, and Earl is forecast to become extratropical by day 4 while it interacts with the aforementioned deep-layer low to the southeast of Atlantic Canada. 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. These swells are likely to cause life-threatening surf and rip current conditions through Friday. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 07/0900Z 25.3N 65.9W 70 KT 80 MPH 12H 07/1800Z 26.4N 65.8W 75 KT 85 MPH 24H 08/0600Z 27.9N 65.6W 85 KT 100 MPH 36H 08/1800Z 29.7N 64.9W 95 KT 110 MPH 48H 09/0600Z 31.8N 63.2W 105 KT 120 MPH 60H 09/1800Z 34.5N 60.1W 110 KT 125 MPH 72H 10/0600Z 37.9N 55.7W 110 KT 125 MPH 96H 11/0600Z 43.6N 48.3W 75 KT 85 MPH...POST-TROP/EXTRATROP 120H 12/0600Z 45.3N 46.7W 50 KT 60 MPH...POST-TROP/EXTRATROP $$ Forecaster Berg |
