ZCZC HFOTCDCP2 ALL TTAA00 PHFO DDHHMM Hurricane Lane Discussion Number 26 NWS Central Pacific Hurricane Center Honolulu HI EP142018 1100 PM HST Mon Aug 20 2018 Lane has quite an impressive satellite signature this evening, with a solid ring of very cold cloud tops surrounding a warming eye. Aircraft from NOAA and the 53rd Weather Reconnaissance Squadron have been flying through lane at 8 to 10 thousand feet respectively this evening, and are confirming that Lane is a powerful hurricane that has intensified since their last visit this morning. The central pressure has dropped roughly 10 mb, peak SFMR winds were 140 kt with max flight level winds near 128 kt, and an eyewall dropsonde recorded winds near 139 kt. Based on a blend of the aircraft data, the initial intensity for this advisory is increased to 130 kt, maintaining Lane as a powerful category 4 hurricane. The initial motion for this advisory is 280/10 kt, with Lane continuing to be steered by a mid-level ridge centered to the north. Over the next couple of days, Lane is expected to reach the western periphery of the ridge, allowing the cyclone to gain latitude. Some increase in the clustering of the track model guidance has occurred this cycle, with the ECMWF no longer on the left hand side of the envelope. All of the reliable model guidance now indicates that Lane will begin to make a gradual turn to the west-northwest by Wednesday, with a gradual slowing in forward speed. A more decided turn toward the northwest is expected Thursday, with relatively slow-moving Lane now forecast to move dangerously close to the main Hawaiian Islands. A turn toward the west is expected in the later forecast periods, with forecast models indicating a weakened Lane increasingly being steered by the low-level trade wind flow. The updated track forecast lies between the previous official forecast and the HCCA. The weakening in the latter forecast periods appears to be related to an increase in vertical wind shear, but it also appears that forecast models are expecting interaction with island terrain to interrupt the low-level wind flow into Lane. Water temperatures along the forecast track will be sufficiently warm to support a major hurricane, and thus any significant weakening before Lane draws closer to the Hawaiian Islands will likely be due to shear. With shear expected to be minimal in the short term, subtle intensity fluctuations associated with inner-core dynamics will likely lead to little overall change in intensity. The later forecast periods anticipate an increase in shear as Lane will lie between the ridge to the east and trough aloft to the northwest of the main Hawaiian Islands, and the updated intensity forecast has been nudged upward in the short term due to recent trends and follows the previous official forecast in the latter forecast periods, close to the IVCN consensus. The uncertainty in the track forecast necessitates that interests in the Hawaiian Islands continue to closely monitor Lane the next couple of days. It is important to not focus on the exact forecast track, as impacts from Lane extend well away from its center. FORECAST POSITIONS AND MAX WINDS INIT 21/0900Z 14.0N 151.2W 130 KT 150 MPH 12H 21/1800Z 14.3N 152.4W 130 KT 150 MPH 24H 22/0600Z 14.7N 153.9W 120 KT 140 MPH 36H 22/1800Z 15.4N 155.1W 115 KT 130 MPH 48H 23/0600Z 16.4N 156.0W 110 KT 125 MPH 72H 24/0600Z 18.9N 157.3W 95 KT 110 MPH 96H 25/0600Z 20.7N 159.0W 75 KT 85 MPH 120H 26/0600Z 21.0N 161.5W 60 KT 70 MPH $$ Forecaster Birchard NNNN