ZCZC HFOTCDCP2 ALL TTAA00 PHFO DDHHMM Hurricane Lane Discussion Number 34 NWS Central Pacific Hurricane Center Honolulu HI EP142018 500 PM HST Wed Aug 22 2018 The eye of Lane has become a bit less distinct in visible and infrared imagery over the past few hours, but the core structure remains well organized. Satellite intensity estimates were 6.0 from SAB and TAFB, and 6.5 from PHFO and JTWC. The CIMSS-ADT remained steady at 6.3. The current intensity was set to 125 kt, based on the consensus of the satellite estimates. Unfortunately Lane appears to have started a more northwest motion, 310/7 over the past several hours. A deep layer ridge to the east and southeast of Lane is expected to build south of the tropical cyclone over the next 24 to 36 hours, which will impart a more northward motion. By 48 to 72 hours, the track guidance begins to show a sharp westward turn, as the low level circulation of Lane decouples in the face of 35 to 40 kt of shear. Exactly when this critical turn will happen is very difficult to forecast, so confidence in this portion of the track is quite low and necessitates expanding the Hurricane Warning to Oahu with this forecast package. The track forecast is virtually unchanged from the previous advisory in this time frame, and now closely follows the HCCA and other consensus guidance, which shifted slightly to the northeast around the time of closest approach to the islands. Beyond 72 hours, the shallow circulation of Lane is expected to be carried westward in the trades. Lane is beginning to move underneath increasing shear as shown in an animation of UW-CIMSS shear analyses. The shear is expected to remain moderate for the first 24 to 36 hours, then become quite strong beyond 48 hours. A gradual weakening trend is shown through 48 hours, with more rapid weakening beyond that time frame. The intensity forecast remains on the high end of the guidance, in best agreement with the ECMWF which maintains the deeper circulation of Lane the longest. KEY MESSAGES: 1. Lane will pass dangerously close to the main Hawaiian Islands as a hurricane Thursday and Friday, and is expected to bring damaging winds. These winds can be accelerated over and downslope from higher terrain, and higher in high rise buildings. 2. The slow movement of Lane also greatly increases the threat for prolonged heavy rainfall, life-threatening flash flooding, and landslides. The flood threat in particular will extend far to the east and northeast of the center of Lane. 3. Large and damaging surf can be expected along exposed shorelines, along with localized storm surge. 4. Do not focus on the exact forecast track or intensity of Lane, and be prepared for adjustments to the forecast. Life threatening impacts can extend well away from the center of a hurricane. FORECAST POSITIONS AND MAX WINDS INIT 23/0300Z 15.9N 156.5W 125 KT 145 MPH 12H 23/1200Z 16.8N 157.2W 125 KT 145 MPH 24H 24/0000Z 18.1N 157.5W 115 KT 130 MPH 36H 24/1200Z 19.2N 157.8W 100 KT 115 MPH 48H 25/0000Z 20.0N 158.2W 85 KT 100 MPH 72H 26/0000Z 20.7N 159.8W 65 KT 75 MPH 96H 27/0000Z 20.3N 162.4W 50 KT 60 MPH 120H 28/0000Z 20.5N 165.5W 40 KT 45 MPH $$ Forecaster R Ballard NNNN