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Tropical Storm Marie Discussion Number  30
NWS National Hurricane Center Miami FL       EP182020
800 AM PDT Tue Oct 06 2020

Marie continues to gradually spin down this morning, and the 
impressive burst of convection that developed near the surface 
center last night, now consists of a shrinking cloud mass with 
significantly warming cloud tops.  Assuming some weakening since 
the last night's METOP-A and B scatterometer passes indicating 
peak winds of 40 kt, the initial intensity is lowered to 35 kt 
which is also supported by a blend of the Dvorak intensity estimates 
from TAFB and SAB.

Marie is moving over cool oceanic sea surface temperatures and 
through a high statically stable air mass.  The persistent, harsh 
vertical shear environment has displaced what remains of the 
cyclone's associated deep convection well to the northeast of the 
center.  The Statistical-dynamical intensity guidance and the 
large-scale models are in general agreement with Marie degenerating 
into a trough of low pressure in 3 days, and the NHC intensity 
forecast follows suit.

The initial motion estimate is estimated to be west-northwestward, 
or 295/8 kt. There are no significant changes to the previous 
forecast track or reasoning.  The cyclone should continue moving 
toward the west-northwest through Wednesday evening.  Through the 
remaining portion of the period, the post-tropical remnant low 
should continue to gradually spin down while moving westward within 
the low-level easterlies and open up into a trough of low pressure 
by Friday.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  06/1500Z 22.1N 135.1W   40 KT  45 MPH
 12H  07/0000Z 22.5N 136.2W   35 KT  40 MPH...POST-TROPICAL
 24H  07/1200Z 22.9N 137.3W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  08/0000Z 23.2N 138.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  08/1200Z 23.2N 138.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  09/0000Z 23.2N 139.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  09/1200Z...DISSIPATED
 
$$
Forecaster Roberts
 
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