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Hurricane Marie Discussion Number  12
NWS National Hurricane Center Miami FL       EP182020
800 PM PDT Thu Oct 01 2020
 
Marie is still strengthening this evening.  Satellite images 
indicate that the hurricane has a well-defined compact eye with a 
ring of cold cloud tops surrounding that feature.  The Dvorak 
classifications at 0000Z were T5.5/102 kt from both TAFB and SAB, 
but since the cyclone has continued to strengthen, the initial 
intensity is increased to 110 kt.  This value is below the latest 
Dvorak ADT numbers that are currently around 6.2/120 kt.  Marie has 
strengthened at an impressive rate of 45 kt over the past 24 hours.
 
Satellite fixes indicate that the hurricane is moving fairly quickly 
to the west-northwest on the south side of a mid-level ridge, with 
the latest initial motion estimated to be 285/13 kt.  The system is 
expected to move slower to the west-northwest or northwest during 
the next several days as it nears the western periphery of the ridge 
and moves toward a broad trough well off the California coast.  The 
models are in fair agreement in the short term, but there is a 
notable amount of spread in the guidance in 4 to 5 days, likely due 
to differences in the vertical depth of Marie and how much the 
trough influences its steering.  The NHC track forecast remains near 
the consensus aids, and is largely an update of the previous one.
 
The major hurricane will likely continue to strengthen during the 
next 12 to 24 hours while it remains in quite favorable conditions 
of low vertical wind shear, a moist air mass, and over warm 28-29 C 
SSTs.  It should be noted that eyewall replacement cycles could 
occur during that time, which might cause fluctuations in the 
cyclone's strength.  By Saturday, Marie is expected to level off in 
intensity and then rapidly weaken when the hurricane crosses the 
26-deg-C SST isotherm and moves into an environment of increasing 
west-southwesterly shear and drier air.  The NHC intensity forecast 
remains above the guidance in the short term, but falls in line with 
the bulk of the models beyond 36 hours.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/0300Z 15.6N 122.1W  110 KT 125 MPH
 12H  02/1200Z 16.3N 123.9W  125 KT 145 MPH
 24H  03/0000Z 17.3N 125.9W  125 KT 145 MPH
 36H  03/1200Z 18.4N 127.4W  115 KT 130 MPH
 48H  04/0000Z 19.4N 128.7W   95 KT 110 MPH
 60H  04/1200Z 20.2N 130.0W   80 KT  90 MPH
 72H  05/0000Z 20.8N 131.5W   65 KT  75 MPH
 96H  06/0000Z 22.0N 134.4W   50 KT  60 MPH
120H  07/0000Z 23.4N 136.4W   35 KT  40 MPH
 
$$
Forecaster Cangialosi
 
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