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#707723 (Received by flhurricane at: 10:42 PM 04.Aug.2014) TCDAT3 HURRICANE BERTHA DISCUSSION NUMBER 17 NWS NATIONAL HURRICANE CENTER MIAMI FL AL032014 1100 PM EDT MON AUG 04 2014 Bertha certainly does not look like a typical hurricane in satellite imagery this evening. The center has become partially exposed to the northwest of the deep convection. A NOAA Hurricane Hunter aircraft that recently investigated the cyclone observed flight-level, SFMR, and dropsonde winds that all supported hurricane intensity late this afternoon. Since that time, the organization has degraded a little and it is possible that Bertha has weakened below hurricane strength. However, new convection has recently formed just east of the center near where the strongest winds were measured earlier. Therefore, the initial intensity is held at 65 kt. This could be generous, but it is best to maintain hurricane status until the the next Hurricane Hunter aircraft examines the storm around 0600 UTC. Bertha is forecast to gradually weaken during the next day or two while it moves into an area of increasing southwesterly vertical wind shear and over decreasing sea surface temperatures. On Wednesday, the cyclone is expected to interact with an approaching mid-latitude trough and Bertha is forecast to become an extratropical cyclone over the North Atlantic shortly thereafter. Fixes from the aircraft show that Bertha is moving a little faster and has turned north-northeastward this evening. The track forecast reasoning remains unchanged. Bertha is expected to accelerate northeastward during the next day or two between a mid-level ridge over the western Atlantic and a deep-layer trough moving off the northeast United States coast. After Bertha becomes a post-tropical cyclone in 48 to 72 hours, it is forecast to turn east-northeastward in the mid-latitude westerly flow over the north Atlantic. FORECAST POSITIONS AND MAX WINDS INIT 05/0300Z 31.3N 73.1W 65 KT 75 MPH 12H 05/1200Z 33.7N 71.9W 60 KT 70 MPH 24H 06/0000Z 36.6N 68.8W 60 KT 70 MPH 36H 06/1200Z 39.3N 64.2W 55 KT 65 MPH 48H 07/0000Z 42.1N 58.9W 55 KT 65 MPH 72H 08/0000Z 47.5N 47.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 09/0000Z 48.5N 31.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 10/0000Z 49.5N 15.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown |