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#940441 (Received by flhurricane at: 4:45 PM 15.Sep.2018) TCDAT5 Tropical Storm Joyce Discussion Number 13 NWS National Hurricane Center Miami FL AL102018 500 PM AST Sat Sep 15 2018 The circulation of Joyce is elongated this afternoon, with the center partially exposed. It has been interesting to watch deep convection firing in the northeastern quadrant, kicking off new small swirls that rotate around the mean circulation. A blend of the Dvorak estimates from TAFB/SAB supports keeping the wind speed 40 kt on this advisory. There is no change to the intensity forecast reasoning. The environment is predicted to be nearly steady-state around Joyce through Sunday, with strong shear being offset by waters near 27C. Thereafter, as the hostile shear continues, the mid-level air should become drier near the center, and SSTs cool off below 26C. These conditions should cause Joyce to slowly weaken early next week, and dissipate in 3 days or so. This forecast is basically the same as the previous one, but it isn`t out of the realm of possibility the cyclone could open up into a trough before that time. Joyce continues to accelerate, now moving east-northeastward at about 15 kt. The storm remains embedded within the same trough as Tropical Storm Helene, and Joyce should move east-northeastward during the next day or so. Beyond that time, as Joyce becomes a shallow cyclone, it is forecast to turn southeastward due to low-level flow around the eastern side of a building ridge over the central Atlantic Ocean. The track forecast is simply an update to the previous one, and continues to be on the southern side of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 15/2100Z 33.1N 39.6W 40 KT 45 MPH 12H 16/0600Z 34.1N 37.2W 40 KT 45 MPH 24H 16/1800Z 34.8N 33.8W 40 KT 45 MPH 36H 17/0600Z 34.8N 30.5W 35 KT 40 MPH 48H 17/1800Z 34.0N 28.0W 30 KT 35 MPH 72H 18/1800Z 31.5N 26.5W 25 KT 30 MPH 96H 19/1800Z...DISSIPATED $$ Forecaster Blake |