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Hurricane EDOUARD Forecast Discussion Number 13
2014-09-14 16:51:30| National Hurricane Center (Atlantic)
Issued at 1100 AM AST SUN SEP 14 2014 000 WTNT41 KNHC 141451 TCDAT1 HURRICANE EDOUARD DISCUSSION NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062014 1100 AM AST SUN SEP 14 2014 Edouard's inner core convective pattern has continued to improve since the previous advisory, with a ring of deep convection surrounding a brief appearance of a 20 nmi diameter eye around 1200 UTC. Since that time, the eye has become cloud-covered with cirrus from a strong convective burst in the western eyewall. A 0924 UTC Windsat microwave overpass revealed good low-level structure and a 15-20 nmi diameter eye. Satellite intensity estimates are a consensus T4.5/77 kt from TAFB and SAB, and UW-CIMSS ADT values have been T4.4/75 kt for the past few hours. However, due to the eye recently becoming cloud-filled, the initial intensity is only being increased to 70 kt, which still makes Edouard the fourth hurricane of the 2014 Atlantic season. Edouard has made slight wobble to the right, possibly due to the formation of the eye, but a 12-hour-average yields a motion of about 305/14 kt. A deep-layer subtropical ridge along 30N-32N latitude is expected to steer the hurricane northwestward today, followed by a turn to the north on Monday and Tuesday. On Wednesday, the cyclone is expected to accelerate to the northeast ahead of a strong mid-tropospheric trough that is forecast to move off of the U.S. east coast. By Days 4 and 5, Edouard is expected to get caught up into the strong mid-latitude westerlies and turn toward the east-northeast. The NHC model guidance is in excellent on this developing steering pattern, and the official forecast closely follows the previous forecast track and the consensus model TVCA. Given the well-developed structure noted in the Windsat imagery, a very favorable poleward outflow pattern forecast to develop by all of the models, and anomalously warm SSTs of 29.5C ahead of the cyclone, there appears to be no physical reason why Edouard should not continue to strengthen and eventually become a major hurricane over the next 2 days or so. The only inhibiting factor could be the dry mid-level air surrounding the cyclone, and that is the only reason why rapid intensification is not being forecast at this time. By Day 4 and beyond, Edouard will be moving over sub-24C SSTs and encountering vertical wind shear greater than 25 kt, which is expected to induce significant weakening. By Day 5, Edouard is forecast to transition to an extratropical cyclone as the system becomes embedded within the strong mid-latitude westerlies. The official intensity forecast follows the trend of the previous forecast and the SHIPS model, except that the timing of the peak intensity has been moved forward by 24 hours, in order to coincide with the time that Edouard will be over the warmest water and in the lowest shear conditions. A NOAA hurricane hunter aircraft is currently conducting a research mission into Edouard. FORECAST POSITIONS AND MAX WINDS INIT 14/1500Z 24.7N 50.7W 70 KT 80 MPH 12H 15/0000Z 25.8N 52.5W 80 KT 90 MPH 24H 15/1200Z 27.1N 54.6W 90 KT 105 MPH 36H 16/0000Z 28.5N 56.1W 100 KT 115 MPH 48H 16/1200Z 30.1N 56.7W 105 KT 120 MPH 72H 17/1200Z 34.5N 54.6W 95 KT 110 MPH 96H 18/1200Z 39.4N 47.1W 75 KT 85 MPH 120H 19/1200Z 41.7N 38.0W 60 KT 70 MPH...POST-TROP/EXTRATROP $$ Forecaster Stewart
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