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