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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
 
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