ZCZC MIATCDEP3 ALL TTAA00 KNHC DDHHMM TROPICAL STORM HERNAN DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP082014 200 AM PDT MON JUL 28 2014 Hernan is now on a weakening trend. The coverage of deep convection has decreased markedly over the past several hours, and the cloud pattern has a more elongated appearance than it did earlier. Microwave images also show a pronounced vertical tilt of the vortex due to about 15 kt of westerly shear. Dvorak and ADT intensity estimates have decreased from all agencies, and using a blend of the CI- and T-numbers yields an initial intensity of 60 kt. A combination of moderate shear, a dry stable air mass, and decreasing sea surface temperatures should cause Hernan to continue weakening during the next few days. The system is expected to become a remnant low in about 2 days when it is forecast to be over waters cooler than 23 C. The storm has turned slightly to the left, and the latest initial motion estimate is 300/13 kt. This general motion should continue for the next 24 hours while Hernan remains steered by a strong mid-level high over the southwestern United States. After that time, a gradual turn to the west with a decrease in forward speed is predicted when the shallow system becomes more influenced by the lighter low-level flow. The official track forecast is just a little to the left of the previous one, and near the multi-model consensus TVCE. FORECAST POSITIONS AND MAX WINDS INIT 28/0900Z 19.9N 114.5W 60 KT 70 MPH 12H 28/1800Z 20.9N 116.4W 50 KT 60 MPH 24H 29/0600Z 22.3N 118.8W 45 KT 50 MPH 36H 29/1800Z 23.4N 120.6W 35 KT 40 MPH 48H 30/0600Z 24.1N 122.2W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 31/0600Z 24.5N 124.2W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 01/0600Z 24.5N 126.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 02/0600Z...DISSIPATED $$ Forecaster Cangialosi NNNN
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Page last modified: Wednesday, 31-Dec-2014 12:09:34 UTC