178 WTPZ45 KNHC 262032 TCDEP5 Hurricane Rosa Discussion Number 7 NWS National Hurricane Center Miami FL EP202018 300 PM MDT Wed Sep 26 2018 Rosa continues to strengthen this afternoon. Improved deep convective banding features with -83C cloud tops are evident in both visible and microwave images, particularly in the east semicircle. The initial intensity is bumped up to 70 kt and is a compromise of the subjective and objective satellite intensity estimates. It still appears likely that Rosa will continue to quickly strengthen through this evening while it moves over warm oceanic temperatures and in a high moisture and low shear atmospheric environment. The official forecast is based on a blend of the IVCN and NOAA-HCCA intensity consensus models, and shows strengthening, at a slower pace, after the RI period. Beyond 48 hours, steady weakening is forecast due to decreasing sea surface temperatures, increasing southwesterly shear, and a high statically stable surrounding environment. Rosa is currently moving west-northwestward, or 285/9 kt, within the mid-level easterly steering flow produced by a mid-level ridge extending from northern Mexico westward over the eastern Pacific. At around day 3, Rosa is expect to move northwestward and then northward day 4 in response to a mid-latitude trough approaching from the northwest. The along track spread beyond day 3 continues to be an issue with the GFS global and HWRF hurricane model indicating a much more faster north to north-northeast motion than the slower European model cluster. In this scenario, the NHC forecast will remain near the better performing various multi-model consensus models. FORECAST POSITIONS AND MAX WINDS INIT 26/2100Z 16.5N 112.2W 70 KT 80 MPH 12H 27/0600Z 16.7N 113.6W 90 KT 105 MPH 24H 27/1800Z 16.9N 115.3W 100 KT 115 MPH 36H 28/0600Z 17.2N 116.7W 105 KT 120 MPH 48H 28/1800Z 17.8N 117.7W 110 KT 125 MPH 72H 29/1800Z 20.1N 119.4W 95 KT 110 MPH 96H 30/1800Z 23.3N 119.2W 80 KT 90 MPH 120H 01/1800Z 26.6N 117.5W 60 KT 70 MPH $$ Forecaster Roberts