000 WTPZ42 KNHC 132046 TCDEP2 Hurricane Linda Discussion Number 15 NWS National Hurricane Center Miami FL EP122021 300 PM MDT Fri Aug 13 2021 Linda has become an impressive looking hurricane this afternoon. The eye that first became evident on geostationary satellite imagery this morning has continued to clear out and warm while the surrounding cold convection associated with the eyewall wraps around the eye. The convective structure on microwave imagery has also improved, with a distinct eye and closed eyewall apparent in an earlier 1417 UTC SSMIS pass. The 1800 UTC subjective and objective Dvorak estimates were in unanimous agreement with T5.5/102 kt provided by SAB, TAFB, and ADT sources. Therefore, the initial intensity has been increased to 100 kt this advisory, making Linda a major hurricane. Linda continues to move steadily to the west-northwest, at 300/12 kt. The track philosophy has not changed much over the past 24 hours. A mid- to upper-level ridge currently centered over the southwestern United States is expected to expand westward, building in to the northwest of the hurricane. This evolution should result in Lisa's motion bending left, first to the west, and then to the west-southwest over the next 2-3 days. The track guidance remains tightly clustered near and just slightly poleward of the previous forecast track. The latest NHC track forecast was nudged just slightly northward over the first few days, but is nearly on top of the previous forecast by the end of the period. Linda has rapidly intensified, with a 35-kt increase over the past 24 hours, and the hurricane still has an opportunity to intensify a bit more over the next 12 hours. After 24 hours, Linda will begin to cross over gradually decreasing sea-surface temperatures and into a and drier mid-level environment. These factors should lead to gradual weakening. One fly in the ointment is that the shear diagnosed by SHIPS guidance is expected to remain low and easterly while sea-surface temperatures remain between 26-27 C through 60 hours. Both the ECMWF and HWRF simulated brightness temperatures during that time suggest that Linda could develop a stable annular structure, which often results in a slower than expected weakening rate. For this reason, the latest intensity forecast only shows gradual weakening through 60 hours, which is a bit above the HCCA consensus aid. More rapid weakening is likely at the end of the forecast period when Linda will move over sub 25 C water. FORECAST POSITIONS AND MAX WINDS INIT 13/2100Z 17.5N 112.9W 100 KT 115 MPH 12H 14/0600Z 18.2N 114.6W 110 KT 125 MPH 24H 14/1800Z 18.9N 116.9W 105 KT 120 MPH 36H 15/0600Z 19.2N 119.2W 100 KT 115 MPH 48H 15/1800Z 19.1N 121.3W 95 KT 110 MPH 60H 16/0600Z 18.7N 123.3W 85 KT 100 MPH 72H 16/1800Z 18.2N 125.2W 75 KT 85 MPH 96H 17/1800Z 17.9N 129.0W 65 KT 75 MPH 120H 18/1800Z 19.0N 133.0W 55 KT 65 MPH $$ Forecaster Papin/Brennan