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Hurricane Marie Discussion Number  13
NWS National Hurricane Center Miami FL       EP182020
200 AM PDT Fri Oct 02 2020

Marie has strengthened further since the last advisory, with 
satellite intensity estimates from TAFB and SAB now at 115 kt and 
the CIMSS ADT estimate now near 130 kt.  However, during the past 
couple of hours, satellite imagery shows that the eye has become 
less well defined.  It is unclear at this time whether this is 
because the hurricane is starting an eyewall replacement or whether 
it has peaked in intensity.  The initial intensity for this 
advisory is increased to a possibly conservative 115 kt.  Marie 
currently has good to excellent cirrus outflow in all directions.

The initial motion is west-northwestward or 295/13 kt as the 
hurricane is being steered by a mid-level ridge to the north.  The 
system is expected to move toward the west-northwest or northwest 
at a slower forward speed during the next several days as it 
approaches the western periphery of the ridge and a broad 
mid-latitude trough well off the California coast.  The track 
guidance remains in good agreement on this scenario through 72 h, 
but there remains increasing spread after that time, which is likely 
due to model differences in the vertical depth of Marie and how much 
the trough influences its steering.  The guidance shifted a little 
to the north of the previous guidance through 72 h, so the new 
forecast track is also nudged northward during that time.  The new 
track is in best agreement with the HCCA corrected consensus model.

If Marie is not undergoing an eyewall replacement cycle, conditions 
appear favorable for additional strengthening during the next  
12-18 h.  After that, the system will be moving over decreasing 
sea surface temperatures and entraining dryer air, which should 
cause weakening.  An faster weakening is expected after 36 h due to 
increasing westerly shear.  The new intensity forecast has minor 
adjustments from the previous forecast, and through 72 h it lies 
near the upper edge of the intensity guidance.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/0900Z 16.2N 123.2W  115 KT 130 MPH
 12H  02/1800Z 16.9N 124.8W  125 KT 145 MPH
 24H  03/0600Z 17.9N 126.5W  120 KT 140 MPH
 36H  03/1800Z 19.0N 127.8W  110 KT 125 MPH
 48H  04/0600Z 19.9N 129.0W   95 KT 110 MPH
 60H  04/1800Z 20.6N 130.2W   80 KT  90 MPH
 72H  05/0600Z 21.1N 131.7W   60 KT  70 MPH
 96H  06/0600Z 22.0N 134.5W   45 KT  50 MPH
120H  07/0600Z 23.5N 136.5W   30 KT  35 MPH
 
$$
Forecaster Beven
 
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