ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM SEYMOUR DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL EP202016 400 PM CDT SUN OCT 23 2016 The cyclone has become better organized during the last several hours. Visible satellite images suggest that an inner core is forming, with a few curved bands surrounding this central convection. The latest Dvorak classifications from TAFB and SAB are 2.5/35 kt, and automated values from CIMSS at the University of Wisconsin are slightly higher. In addition, an ASCAT pass around 1600 UTC showed maximum winds in the 30 to 35 kt range. Based on these data, the initial wind speed is increased to 35 kt. The global models are in agreement that Seymour should remain in a favorable upper-level wind pattern during the next few days. These light upper-level winds, combined with very warm water and high mid-level moisture values should allow Seymour to steadily, or perhaps rapidly, strengthen during the next 72 hours. Beyond that time, a significant increase in southwesterly shear, cooler waters, and a decrease in moisture should end the strengthening trend and induce weakening. The NHC intensity forecast is raised from the previous one, and is near the middle of the guidance envelope. The tropical storm is moving west-northwestward at 12 kt. A mid-level ridge over Mexico should continue to steer Seymour west-northwestward at a slightly slower pace during the next few days. After that time, the ridge is likely to erode as a deep- layer low pressure moves eastward toward California. This pattern change will likely cause Seymour to turn northwestward and then northward in 4 to 5 days. The models have shifted considerably to the right at the longer range points, and the new NHC track forecast has been adjusted in that direction. FORECAST POSITIONS AND MAX WINDS INIT 23/2100Z 13.9N 105.9W 35 KT 40 MPH 12H 24/0600Z 14.5N 107.8W 40 KT 45 MPH 24H 24/1800Z 15.2N 110.2W 50 KT 60 MPH 36H 25/0600Z 15.8N 112.7W 60 KT 70 MPH 48H 25/1800Z 16.4N 115.1W 70 KT 80 MPH 72H 26/1800Z 17.8N 119.0W 75 KT 85 MPH 96H 27/1800Z 20.8N 121.1W 55 KT 65 MPH 120H 28/1800Z 23.1N 120.7W 35 KT 40 MPH $$ Forecaster Cangialosi NNNN