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Tropical Storm Maria Forecast Discussion Number 45
2017-09-27 10:36:17| National Hurricane Center (Atlantic)
Issued at 500 AM EDT Wed Sep 27 2017 000 WTNT45 KNHC 270836 TCDAT5 Tropical Storm Maria Discussion Number 45 NWS National Hurricane Center Miami FL AL152017 500 AM EDT Wed Sep 27 2017 Maria has changed little in structure since the last advisory. A band of deep convection attempted to wrap around the western side of the circulation, but that has since dissipated due to continued shear and dry air. The initial intensity remains 60 kt based on surface winds measured by the SFMR on the previous reconnaissance flight. Maria will likely be moving over some warm and cold eddies associated with the Gulf Stream during the next 2 to 3 days, and with vertical shear expected to gradually decrease during that time, only slow weakening is anticipated. After day 3, vertical shear increases significantly, and Maria is expected to complete extratropical transition by day 4. The global models then indicate that the low will be absorbed by a larger extratropical low over the northeastern Atlantic by day 5. Earlier reconnaissance fixes indicated that Maria's center was jumping around a bit, but its average motion is estimated to be slowly northward, or 005 degrees at 4 kt. Maria is moving around the western periphery of a mid-level ridge located over the central Atlantic, and it should enter the mid-latitude westerlies in about 36 hours, at which point it is expected to accelerate northeastward across the north Atlantic. Most of the model spread continues to be in the along-track direction, highlighted by the faster GFS and HWRF models and the slower ECMWF model. As was the case before, the updated NHC track forecast splits the difference between these scenarios and remains close to the multi-model consensus aids. KEY MESSAGES: 1. Maria is forecast to slowly move away from the U.S. east coast during the next day or so. However, tropical storm conditions are expected to continue along portions of the North Carolina coast through much of today. 2. Storm surge flooding, especially along the sound side of the North Carolina Outer Banks, is expected, and a storm surge warning and watch are in effect for portions of eastern North Carolina. 3. Swells generated by Maria are affecting much of the east coast of the United States, Atlantic Canada, Bermuda, the Bahamas, and the Turks and Caicos Islands. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office for more information. FORECAST POSITIONS AND MAX WINDS INIT 27/0900Z 35.1N 72.9W 60 KT 70 MPH 12H 27/1800Z 35.7N 72.7W 55 KT 65 MPH 24H 28/0600Z 36.2N 71.7W 55 KT 65 MPH 36H 28/1800Z 36.5N 69.3W 50 KT 60 MPH 48H 29/0600Z 37.0N 65.3W 50 KT 60 MPH 72H 30/0600Z 40.5N 52.5W 50 KT 60 MPH 96H 01/0600Z 47.5N 32.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 02/0600Z...ABSORBED BY A LARGER EXTRATROPICAL LOW $$ Forecaster Berg
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