ZCZC HFOTCDCP2 ALL TTAA00 PHFO DDHHMM Hurricane Lane Discussion Number 24 NWS Central Pacific Hurricane Center Honolulu HI EP142018 1100 AM HST Mon Aug 20 2018 Air Force Reserve Hurricane Hunters found a maximum flight level wind of 121 kt, and the NOAA Hurricane Hunters found maximum SFMR wind of 113 kt earlier on the northwest quadrant. The 15 to 20 nm diameter eye had also temporarily become more distinct over the past 6 to 8 hours, and this was the justifiation for raising the current intensity slightly to 115 kt. This is somewhat higher than the 18z satellite based estimates were showing. The eye has since started to become less distinct once again in satellite imagery. The initial motion is 280/10, slightly slower than the previous advisory. Lane is marching toward the west on the southern flank of a large subtropical ridge. In the near term, the track guidance is in excellent agreement. This motion is expected to gradually turn more toward the west-northwest, and then finally northwest over the next few days as the ridge weakens and erodes. Beyond 48 hours, the forecast becomes quite challenging. The guidance shows increasing spread due to noteworthy differences in the handling of the strength of the ridge to the east and southeast of the cyclone. The GFS remains on the far right side of the guidance with a harder right turn starting around 72 hours, and the ECMWF shows a more gentle curve. The consensus guidance remains split down the middle of these two camps and did not change much from the previous advisory. The forecast track at 96 hours was nudged slightly eastward to better agree with the consensus guidance, but it should be noted that in this situation, forecast confidence is lower than normal. A turn back toward the west-northwest is expected toward the end of the forecast period as strong wind shear begins to impact Lane, but this is also a rather low confidence scenario. Lane is expected to remain over 28C sea surface temperatures in the short term in a weak to moderate shear environment that should allow the hurricane to maintain intensity. After a day or two, the models show increasing shear beginning to work on the circulation and weaken the system. However, there are some differences as to when that will begin. The intensity forecast shows a slow weakening trend beginning in the 24 to 36 hour time frame in good agreement with the intensity consensus guidance. Once shear increases in the 48 to 72 hour time frame, a somewhat faster weakening trend is anticipated which should continue through the rest of the forecast period. Interests in the main Hawaiian Islands, as well as the northwestern Hawaiian Islands, should continue to monitor the progress of Lane this week. With such a complex forecast scenario, it is especially important not to focus on the exact forecast track and intensity and be ready for changes to both. FORECAST POSITIONS AND MAX WINDS INIT 20/2100Z 13.6N 149.1W 115 KT 130 MPH 12H 21/0600Z 13.7N 150.6W 115 KT 130 MPH 24H 21/1800Z 13.9N 152.3W 115 KT 130 MPH 36H 22/0600Z 14.3N 153.9W 110 KT 125 MPH 48H 22/1800Z 14.9N 155.3W 105 KT 120 MPH 72H 23/1800Z 16.9N 157.2W 95 KT 110 MPH 96H 24/1800Z 19.4N 158.8W 75 KT 85 MPH 120H 25/1800Z 20.6N 160.4W 55 KT 65 MPH $$ Forecaster R Ballard NNNN