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Hurricane Erick Discussion Number  20
NWS Central Pacific Hurricane Center Honolulu HI   EP062019
1100 PM HST Wed Jul 31 2019
 
Although Erick's presentation in conventional infrared satellite
imagery continues to deteriorate this evening, deep convection
persists over the core, and microwave imagery (especially a 0357Z
SSMIS pass) indicates that an eye remains intact. Subjective Dvorak
estimates agree that Erick remains a hurricane, with a blend of
these estimates supporting an initial intensity of 80 kt for this
advisory, although ADT and SATCON from UW-CIMSS suggest that Erick
is weaker.
 
Locating the center of the hurricane is somewhat uncertain, leading
to reduced confidence in an initial motion estimate of 290/11 kt.
The track forecast continues to expect a general motion just
north of due west for most of the forecast period, with a low- to
mid-level ridge centered to the north and northeast respectively
providing the primary steering, especially as Erick becomes
increasingly shallow. The official forecast was nudged equatorward
and is a little faster than the previous forecast through the first
72 hours, close to the UKMET and ECMWF, which have the been the top
performers with Erick to this point. Thereafter, little change to
the forecast was made. 
 
Erick is moving into an area of strong vertical wind shear, with
low-level easterlies supported by the ridge to the north, and upper-
level westerlies associated with a semi-permanent trough axis
northwest of the main Hawaiian islands. According to UW-CIMSS
analyses, shear values along the forecast track increase to 30-40 kt
over the next 12 to 24 hours. This unrelenting shear is expected to
lead to the demise of Erick as a tropical cyclone by the end of the
forecast period. The dynamical and statistical guidance indicates
that Erick's recent rapid decay will continue, and it will barely be
hanging on as a tropical storm in 48 hours. The rate of weakening
depicted in the official forecast closely follows, and Erick is now
expected to become a remnant low on days 4 and 5 before dissipating
shortly thereafter.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  01/0900Z 15.5N 150.9W   80 KT  90 MPH
 12H  01/1800Z 15.7N 152.6W   65 KT  75 MPH
 24H  02/0600Z 16.2N 155.3W   50 KT  60 MPH
 36H  02/1800Z 16.6N 158.0W   45 KT  50 MPH
 48H  03/0600Z 17.2N 160.4W   35 KT  40 MPH
 72H  04/0600Z 18.6N 164.5W   30 KT  35 MPH
 96H  05/0600Z 20.0N 167.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  06/0600Z 21.5N 169.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Birchard
 
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