ZCZC HFOTCDCP2 ALL TTAA00 PHFO DDHHMM Hurricane Lane Discussion Number 21 NWS Central Pacific Hurricane Center Honolulu HI EP142018 500 PM HST Sun Aug 19 2018 Lane's satellite presentation has not changed much since late this morning. The main features include a murky cloud-filled eye surrounded by a symmetric convective ring. Outflow is best to the north through northeast, but remains somewhat constricted elsewhere in the face of 17 kt of UW-CIMSS-derived southwest vertical shear. The coldest cloud tops, -75 to -80 degrees C, are within the north quadrant of the convective ring. The latest subjective Dvorak intensity estimates range from 5.0/90 kt (SAB) to 6.0/115 kt (PHFO). JTWC estimated 5.5/102 kt while UW-CIMSS estimated 5.0/90 kt. The initial intensity for this package is set at 105 kt, representing a slight adjustment downward using a blend of estimates. Initial motion is a steady 280/12 kt as Lane continues tracking westward along the southern flank of a large subtropical ridge. There is still quite a bit of spread in track guidance beyond day 2 as individual models handle the erosion of the western portion of this ridge differently, thanks to the forecast intrusion of a weak frontal band far northwest of the main Hawaiian Islands. GFS and HWRF represent the northern edge of the guidance envelope, while ECMWF lies along the southern edge. The current forecast track lies within the southern third of the guidance envelope, closely following FSSE and TVCX consensus through 96 hours, then bending left at 120 hours and beyond between TVCX and ECMWF guidance. The only noticeable change from the previous track is a slight bump to the right beyond day 4 to account for an overall guidance envelope shift to the right at days 4 and 5. The NOAA G-IV aircraft has completed its initial synoptic sweep around Lane and the main Hawaiian Islands, and the NOAA P-3 aircraft is about to start its mission as of this writing. Air Force Reserve WC-130J aircraft will begin their sampling missions through Lane this evening. The valuable data collected during these missions will be used to better initialize the guidance models and, hopefully, reduce the guidance envelope spread. The intensity forecast follows the logic of the previous one, only with a slightly lower initial intensity. Lane will remain over 27-28 degree C waters through the forecast period, with 10 to 20 kt of vertical shear through most of its track, at least according to the ECMWF-derived SHIPS run. Gradual weakening is forecast through the forecast period, closely following the shape of the DSHIP and FSSE intensity curves but staying above the IVCN intensity curve. Lane is forecast to pass south of the main Hawaiian Islands Wednesday and Thursday, potentially causing local impacts as it tracks west-northwestward. Interests in these islands should watch the progress of Lane closely, since long-range track and intensity forecast errors can be large. FORECAST POSITIONS AND MAX WINDS INIT 20/0300Z 13.8N 145.8W 105 KT 120 MPH 12H 20/1200Z 14.1N 147.5W 100 KT 115 MPH 24H 21/0000Z 14.4N 149.6W 100 KT 115 MPH 36H 21/1200Z 14.6N 151.2W 95 KT 110 MPH 48H 22/0000Z 14.9N 152.9W 90 KT 105 MPH 72H 23/0000Z 15.6N 156.2W 80 KT 90 MPH 96H 24/0000Z 17.0N 159.3W 70 KT 80 MPH 120H 25/0000Z 19.1N 161.8W 60 KT 70 MPH $$ Forecaster Powell NNNN