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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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