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#940666 (Received by flhurricane at: 10:51 PM 16.Sep.2018) TCDAT5 Tropical Depression Joyce Discussion Number 18 NWS National Hurricane Center Miami FL AL102018 1100 PM AST Sun Sep 16 2018 Joyce is managing to maintain tropical cyclone status despite very strong westerly vertical wind shear. The system still displays cold cloud tops, but only within the northeast quadrant and at least 100 nm from the center. The shear is being induced primarily by 50-kt 200 mb winds. Usually such strong vertical shear would completely decapitate a tropical cyclone. However, systems in higher latitudes and moving in the same direction as the shear vector tend to be somewhat more resilient to the detrimental effects of the shear. Nonetheless, it is anticipated that Joyce will soon succumb to the combination of high shear, cool waters, and dry mid-levels, and become a remnant low within 48 hours, if not sooner. The official intensity forecast shows a gradual weakening, nearly the same as the previous advisory and based upon a blend of the LGEM statistical scheme and the HWRF/HMON dynamical models. Joyce is moving toward the east at a quick 18-kt clip. The system has not been picked up by the mid-latitude westerlies and is expected to be advected around the lower tropospheric Bermuda-Azores high. Joyce should slow its forward speed and turn toward the southeast (on Monday), the south (on Tuesday), and finally the southwest (on Wednesday) before dissipating in about four days. The track forecast is based upon the tightly clustered TVCN multi-model consensus and is slightly farther east because of the quicker eastward initial motion than previously observed. FORECAST POSITIONS AND MAX WINDS INIT 17/0300Z 34.0N 30.3W 30 KT 35 MPH 12H 17/1200Z 33.7N 27.9W 30 KT 35 MPH 24H 18/0000Z 32.8N 26.5W 30 KT 35 MPH 36H 18/1200Z 31.7N 26.3W 25 KT 30 MPH 48H 19/0000Z 30.5N 27.1W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 20/0000Z 28.9N 29.8W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 21/0000Z...DISSIPATED $$ Forecaster Landsea |