ZCZC MIATCDAT1 ALL TTAA00 KNHC DDHHMM HURRICANE EDOUARD DISCUSSION NUMBER 25 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062014 1100 AM AST WED SEP 17 2014 Edouard is maintaining two concentric rings as indicated in the latest visible satellite images and recent NOAA Hurricane Hunter aircraft wind data. Even though the central pressure is rather low, 958 mb, the pressure gradient is spread out over the large area comprising the two rings, leading to a lower peak wind than a typical cyclone would have. Flight-level and SFMR winds still support an intensity of about 80 kt, which is unchanged from the previous estimate. Edouard is accelerating northeastward with a motion of 045/20 kt. The hurricane is being steered by mid-latitude flow between the subtropical ridge and a broad trough over the western Atlantic Ocean. This pattern should force Edouard to move faster toward the east-northeast by late tonight, and eastward by late tomorrow. In a couple of days, Edouard (or its remnants) should turn southward to the west of the Azores around a large trough over the eastern Atlantic Ocean. The track guidance remains tightly clustered for the first 48 hours but continues to show some divergence during the post-tropical phase. The ECMWF has remained consistent on a sharper southward turn, while the GFS is showing a more gradual equatorward motion. Because of the consistency of the ECMWF during the past few runs, the latest NHC track is staying on the southwest side of the model envelope at long range, roughly halfway between the model consensus and the ECMWF. Edouard is moving quickly toward the northeast and should pass over waters cooler than 26C in less than 12 hours. Only a gradual weakening is shown during the first 24 hours due to cooler waters and moderate shear. All of the global models show a sharp increase in shear after that time while the cyclone is moving over much colder water. Thus a more rapid weakening is shown beginning late tomorrow, which is similar to a blend of the previous NHC forecast, the Florida State Superensemble, and the intensity consensus. The cyclone is expected to become post-tropical in 2 or 3 days, which is in good agreement with the global models. Although Edouard is expected to traverse warmer waters by the end of the forecast period, strong northwesterly shear is anticipated to hinder any redevelopment potential. FORECAST POSITIONS AND MAX WINDS INIT 17/1500Z 36.4N 53.3W 80 KT 90 MPH 12H 18/0000Z 38.3N 49.9W 75 KT 85 MPH 24H 18/1200Z 39.8N 44.7W 70 KT 80 MPH 36H 19/0000Z 40.1N 40.7W 55 KT 65 MPH 48H 19/1200Z 39.7N 38.7W 40 KT 45 MPH 72H 20/1200Z 39.4N 35.8W 35 KT 40 MPH...POST-TROPICAL 96H 21/1200Z 37.5N 33.5W 30 KT 35 MPH...POST-TROPICAL 120H 22/1200Z 34.5N 33.0W 30 KT 35 MPH...POST-TROPICAL $$ Forecaster Blake NNNN