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Hurricane Aletta Discussion Number  13
NWS National Hurricane Center Miami FL       EP022018
300 PM MDT Fri Jun 08 2018

Aletta remains a formidable category 4 hurricane, although there
has been some weakening of the core convection during the day.  The
current intensity is held at 120 kt which is a blend of subjective
Dvorak estimates from TAFB and SAB along with objective Dvorak
values.  After the notable strengthening episode over the last 24
hours, it appears that the intensity has leveled off.  This is
also consistent with GOES-16 measurements of increased inner-core
lightning observed to be occurring to the east of the eastern
eyewall, which some research suggests corresponds to a halting of
the intensification process.  Since vertical shear is expected to
increase in 12 to 24 hours, a weakening trend is forecast to begin
late tonight or tomorrow. A more rapid weakening will likely
commence on Sunday as Aletta begins to traverse cooler waters.  The
official intensity forecast is at the upper bound of the numerical
guidance.

The hurricane has moved on a more westward course today, and the
initial motion estimate is now 290/5 kt.  Aletta is moving along
the southwestern periphery of a mid-level high pressure area and
should continue to do so over the next day or two.  Later in the
forecast period, the weakening and increasingly shallower cyclone
should turn westward and south of westward, following the low-level
tradewind flow.  The official forecast is close to the dynamical
model consensus TVCE and is somewhat south of the previous NHC
track.

FORECAST POSITIONS AND MAX WINDS

INIT  08/2100Z 16.0N 111.7W  120 KT 140 MPH
 12H  09/0600Z 16.5N 112.6W  120 KT 140 MPH
 24H  09/1800Z 17.2N 113.6W  100 KT 115 MPH
 36H  10/0600Z 17.9N 114.5W   75 KT  85 MPH
 48H  10/1800Z 18.3N 115.4W   55 KT  65 MPH
 72H  11/1800Z 18.6N 117.5W   30 KT  35 MPH
 96H  12/1800Z 18.6N 119.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  13/1800Z 18.0N 121.0W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Pasch

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