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#717902 (Received by flhurricane at: 10:56 PM 15.Sep.2014) TCDAT1 HURRICANE EDOUARD DISCUSSION NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062014 1100 PM AST MON SEP 15 2014 Edouard has not strengthened further. While the eye has become somewhat better defined and warmer since the last advisory, deep convection in the central dense overcast is not quite as cold. The intensification phase that the cyclone was experiencing earlier may have been interrupted by 15-20 kt of southeasterly shear as analyzed by the SHIPS model output and UW-CIMSS analyses. Dvorak intensity estimates remain a consensus T5.0/90 kt from TAFB and SAB, while UW-CIMSS CI values are around T5.6/105kt. A blend of these data is used to hold the initial intensity at 95 kt. Edouard still has another 24-36 hours to intensify. Moderately strong southeasterly shear, resulting from the flow between a low to the southwest and a high to the east at upper levels, is forecast to decrease as Edouard nears its point of recurvature. Near and immediately after that time, the shear and motion vectors should align, which tends to favor more symmetric convection. These favorable factors, despite gradually cooler waters beneath the cyclone, should allow Edouard to reach major hurricane status. Drastically cooler waters and a substantial increase in southwesterly shear beyond 48 hours suggest that a rapid decay of the cyclone should occur by that time. Interaction with a baroclinic zone in 2-3 days should cause the beginning of extratropical transition, but this process is expected to become interrupted when the cyclone shears apart and outruns this weather system. Edouard is likely to become a post-tropical cyclone in 96 hours, if not slightly sooner, and gradually spin down over the northeastern Atlantic. The NHC wind speed forecast is the same as the previous one through 48 hours and is above all of the intensity guidance. The forecast is lowered relative to the last advisory after that time and is near the multi-model consensus IVCN. Edouard has recently turned north-northwestward and the initial motion estimate is now 335/11. The track guidance remains in excellent agreement through 72 hours. The cyclone is expected to turn northward in 12-18 hours when it rounds the western periphery of a subtropical ridge. An acceleration toward the northeast, and then east-northeast, is expected beyond 24 hours as Edouard is captured by a relatively fast-paced westerly flow over the north Atlantic. Near the end of the forecast period, the increasingly shallow vortex should turn eastward and southeastward within the flow on the west side of a deep-layer low over the northeast Atlantic. The track guidance has shifted noticeably to the left on this cycle. However, to maintain continuity, the new NHC track forecast is only nudged to the left of the previous one, and lies on the far right side of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 16/0300Z 29.0N 56.9W 95 KT 110 MPH 12H 16/1200Z 30.5N 57.3W 100 KT 115 MPH 24H 17/0000Z 32.8N 56.6W 105 KT 120 MPH 36H 17/1200Z 35.5N 54.3W 95 KT 110 MPH 48H 18/0000Z 38.1N 50.4W 80 KT 90 MPH 72H 19/0000Z 40.9N 41.3W 60 KT 70 MPH 96H 20/0000Z 40.0N 36.0W 45 KT 50 MPH...POST-TROPICAL 120H 21/0000Z 38.6N 32.3W 35 KT 40 MPH...POST-TROPICAL $$ Forecaster Kimberlain |