441 WTPZ42 KNHC 060238 TCDEP2 Hurricane Olivia Discussion Number 21 NWS National Hurricane Center Miami FL EP172018 800 PM PDT Wed Sep 05 2018 Olivia continues to have a large and distinct eye, but the surrounding convection has not changed in the past 6 h or so. Dvorak numbers are steady, and a blend of objective and subjective estimates yield an initial intensity of 85 kt. The shear is not a problem for Olivia since it is forecast to remain low through the entire 5-day period. However, in about a day, the SSTs along Olivia's track will decrease resulting in a gradual weakening of the cyclone. The NHC intensity forecast is similar to the previous one, and follows the intensity consensus. There has been no change in track, and Olivia is still moving toward the west-northwest or 285 degrees at 12 kt. The subtropical ridge is anchored north of the hurricane, and this flow pattern should continue to steer Olivia on the same general track for he next 5 days. By the end of the forecast period, the ridge is expected to expand westward, forcing the cyclone to move westward. Track models are in an excellent agreement, and the guidance envelope remains tightly clustered for the next 3 days. After that time, although the envelope widens a little bit, models still indicate a westward-moving cyclone. The NHC forecast is in the middle of the envelope and very close to the multi-model aids. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 17.7N 124.6W 85 KT 100 MPH 12H 06/1200Z 18.2N 126.5W 80 KT 90 MPH 24H 07/0000Z 18.9N 129.1W 80 KT 90 MPH 36H 07/1200Z 20.0N 132.0W 75 KT 85 MPH 48H 08/0000Z 20.8N 134.5W 70 KT 80 MPH 72H 09/0000Z 21.8N 139.7W 60 KT 70 MPH 96H 10/0000Z 22.0N 144.5W 55 KT 65 MPH 120H 11/0000Z 22.0N 149.0W 55 KT 65 MPH $$ Forecaster Avila