592 WTPZ44 KNHC 152034 TCDEP4 Tropical Storm Lane Discussion Number 4 NWS National Hurricane Center Miami FL EP142018 200 PM PDT Wed Aug 15 2018 Satellite images indicate that Lane is strengthening. The central dense overcast continues to grow, with a large banding feature in the western semicircle and expanding outflow in most quadrants. ASCAT data recently showed maximum winds of about 40 kt, so that will be the initial wind speed, which is also near a blend of the latest Dvorak estimates from TAFB and SAB. While the latest microwave data indicate that the inner core of Lane remains loosely organized, the large-scale environment appears to be favorable for intensification. Low shear, warm waters of 27.5-28C, and moderate levels of mid-level moisture all support strengthening at a higher rate than climatology. However, since the inner core is not well established yet, the intensity forecast will be held just below rapid strengthening (30 kt in 24 h) for day 1. There is still a strong signal for that threshold to be met in the day 2-3 period from the DTOPS rapid intensification index, so the forecast will remain for a major hurricane to form during that time. This forecast is close to a blend of the latest NOAA-HCCA and FSSE corrected consensus models. The storm continues to move just south of due west, now at about 11 kt. The synoptic pattern is well established with a subtropical ridge expected to only slightly weaken in the medium-range period, causing a slight west-northwestward turn in the central Pacific. While the overall spread has increased in the 1200 UTC guidance, the latest model consensus has barely budged since the previous advisory, although it does fit the recent westward trend. The latest official track forecast is again adjusted in that direction, close to the eastern Pacific track model consensus TVCE. FORECAST POSITIONS AND MAX WINDS INIT 15/2100Z 10.6N 124.5W 40 KT 45 MPH 12H 16/0600Z 10.5N 126.2W 50 KT 60 MPH 24H 16/1800Z 10.7N 128.4W 65 KT 75 MPH 36H 17/0600Z 11.1N 130.9W 80 KT 90 MPH 48H 17/1800Z 11.6N 133.6W 95 KT 110 MPH 72H 18/1800Z 12.6N 138.7W 105 KT 120 MPH 96H 19/1800Z 14.0N 143.6W 110 KT 125 MPH 120H 20/1800Z 15.2N 148.2W 105 KT 120 MPH $$ Forecaster Blake