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Hurricane Marie Discussion Number  22
NWS National Hurricane Center Miami FL       EP182020
800 AM PDT Sun Oct 04 2020
 
Conventional satellite imagery reveals an increasingly apparent 
asymmetric/vertical tilt due to persistent west-southwesterly 
shear.  The surface center is beginning to become exposed and is 
now near the western edge of the deep convective mass.  The initial 
intensity is lowered to 80 kt for this advisory and is based on a 
compromise of the available subjective and objective satellite 
intensity estimates.  Weakening should continue rather quickly 
through the forecast period while the shear magnitude increases 
with time and the cyclone traverses cooler oceanic surface 
temperatures.  Marie should degenerate to a post-tropical remnant 
low in 3 days, or less, and this is in agreement with the majority 
of the global/regional and statistical guidance.  The intensity 
forecast is near the IVCN intensity consensus and above the ECMWF 
and GFS Decay SHIPS which actually show dissipation in less than 4 
days.
 
Maria's initial motion is estimated to be northwestward, or 315/6 
kt, within the mid-tropospheric steering flow provided by a 
subtropical ridge anchored to the north of the cyclone.  Marie 
should continue moving in either a west-northwestward or 
northwestward motion through the remainder of forecast period with 
some reduction in forward speed, day 3 and beyond.  The NHC 
forecast track has been adjusted a little bit south of the previous 
advisory after the 24 hour period in order to be closer to the 
various multi-model consensus aids and to conform more with a motion 
typical of a shallower, vertically limited system moving through the 
trade wind flow.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  04/1500Z 20.3N 128.6W   80 KT  90 MPH
 12H  05/0000Z 20.7N 129.5W   65 KT  75 MPH
 24H  05/1200Z 21.3N 131.0W   55 KT  65 MPH
 36H  06/0000Z 22.0N 132.3W   45 KT  50 MPH
 48H  06/1200Z 22.7N 133.9W   35 KT  40 MPH
 60H  07/0000Z 23.4N 135.2W   30 KT  35 MPH
 72H  07/1200Z 24.0N 136.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  08/1200Z 24.8N 136.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  09/1200Z 25.3N 137.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Roberts
 
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