ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM DOLORES DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP052015 900 AM MDT MON JUL 13 2015 Dolores is gradually intensifying. The cyclone is maintaining a symmetric and very cold-topped central dense overcast, with the center fully underneath the deepest convection. Very recently the cyclone has also shed its outer bands while the inner core has increased in organization. The outflow remains somewhat restricted to the west, however, and there still is some evidence of west- northwesterly shear as a result of an upper-level trough to the northwest. Dvorak classifications were T3.5/55 kt from both TAFB and SAB at 1200 UTC. Since that time, there has been some further increase in organization, and thus the initial intensity is set to 60 kt. The initial motion estimate continues to be a steady 295/11. Dolores should continue to be steered west-northwestward by a subtropical ridge over the south-central United States during the next couple of days. As the cyclone approaches the western periphery of this ridge, the forward motion should decrease and the heading should become west-northwestward to northwestward in 48 to 72 hours. After that time, the ridge should rebuild somewhat to the northeast, which should result in a slightly faster forward speed late in the forecast period. The GFS and ECMWF model solutions diverge considerably after 72 hours, owing to the strength of the subtropical ridge. The official forecast is a little right of the previous one through 36 hours and very close to the multi-model consensus after that time since the strength of the subtropical ridge is still uncertain late in the forecast period. Although environmental thermodynamics are quite conducive for intensification, global models continue to show a persistent west- northwesterly shear over Dolores during the next 24 hours. The shear, however, has not been enough to impede strengthening, with the cyclone developing at about the standard T-number/day climatological average. SHIPS model output indicates a decrease in shear in about 36 hours, and Dolores is expected to become a major hurricane not long after that time. With decreasing SSTs and a drier and more stable atmosphere along Dolores' path after 96 hours, the cyclone is forecast to gradually spin down. Ultimately, the rate of decay will depend on how quickly Dolores gains latitude late in the forecast period. The official intensity forecast is generally above the multi-model consensus and closest to SHIPS model output. FORECAST POSITIONS AND MAX WINDS INIT 13/1500Z 17.1N 106.0W 60 KT 70 MPH 12H 14/0000Z 17.5N 107.0W 70 KT 80 MPH 24H 14/1200Z 17.8N 108.0W 80 KT 90 MPH 36H 15/0000Z 18.1N 109.0W 90 KT 105 MPH 48H 15/1200Z 18.4N 109.8W 100 KT 115 MPH 72H 16/1200Z 19.7N 112.0W 105 KT 120 MPH 96H 17/1200Z 21.2N 115.0W 90 KT 105 MPH 120H 18/1200Z 22.7N 118.3W 70 KT 80 MPH $$ Forecaster Kimberlain NNNN