ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM DOLORES DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL EP052015 400 AM CDT MON JUL 13 2015 Dolores' convective cloud pattern has continued to improve overnight with a distinct CDO now evident along with a large curved band in the eastern semicircle. In addition, a warm spot has recently appeared near the center of the CDO, a possible precursor to the development of an eye. The ship Asia Excellence, call sign C6AX5, traversed the northeastern quadrant during the past several hours and reported winds of 55 kt. Based on that report and a UW-CIMSS ADT intensity estimate of T3.7/59 kt, the intensity of Dolores has been increased to 55 kt. The initial motion estimate is 290/11 kt, and is based on continuity with the previous forecast and limited microwave fix data. The NHC model guidance is in decent agreement on Dolores maintaining a west-northwestward motion along with a decrease in forward speed through the forecast period as a strong ridge to its north holds steady. Some spread in the models occurs after 48 hours due to differences in how they handle the large trough along the U.S. west coast and how much it erodes the western portion of the ridge over the U.S. desert southwest and northwestern Mexico. The reliable ECMWF and GFS global models, and the regional HWRF model, keep the ridge intact across Baja California, and the official track forecast follows this scenario by keeping Dolores well to the south and southwest of Baja California. The latest NHC forecast lies close to a blend of those three model tracks. Dolores is expected to remain over SSTs greater than 28C for the next 48 hours or so, during which time the deep-layer vertical shear is expected to gradually weaken, especially after 24 hours when the shear is forecast to decrease to less than 5 kt. This combination, along with a moist mid-level environment, should allow for Dolores to continue to strengthen into a significant hurricane. Around 96-120 hours, Dolores is forecast to move over SSTs less than 26C, which should induce gradual weakening. The NHC intensity forecast is similar to the previous advisory and follows the trend of the Decay-SHIPS intensity model, which essentially brings Dolores to major hurricane status by 48-72 hours. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 16.6N 105.0W 55 KT 65 MPH 12H 13/1800Z 16.9N 106.1W 65 KT 75 MPH 24H 14/0600Z 17.1N 107.3W 75 KT 85 MPH 36H 14/1800Z 17.4N 108.2W 80 KT 90 MPH 48H 15/0600Z 17.9N 109.1W 85 KT 100 MPH 72H 16/0600Z 19.2N 111.0W 100 KT 115 MPH 96H 17/0600Z 20.6N 113.6W 90 KT 105 MPH 120H 18/0600Z 21.8N 116.6W 75 KT 85 MPH $$ Forecaster Stewart NNNN