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Tropical Storm Marie Discussion Number  29
NWS National Hurricane Center Miami FL       EP182020
1100 PM HST Mon Oct 05 2020
 
A 6/0630Z ASCAT-B scatterometer overpass indicated that Marie has 
refused to weaken despite the deep convection being severely sheared 
to the northeast of the low-level center. A solid area of 40-kt was 
present northwest through northeast of the center, with a couple of 
45-kt vectors present. However, the 45-kt vectors look like they 
could have been rain enhanced, so the initial intensity remains at 
40 kt for this advisory.

The initial motion estimate is 300/08 kt. There are no significant 
changes to the previous forecast track or reasoning. Marie is 
expected to move slowly west-northwestward along the southern 
periphery of a deep-layer ridge for the next 24 hours or so, during 
which time the cyclone will gradually spin down and become more 
vertically shallow. Thereafter, and continuing until dissipation 
occurs, a more westward motion is anticipated when the shallow 
system will be steered by the low-level easterly tradewind flow. The 
new NHC forecast track is similar to but a tad north of the 
previous advisory track, and lies near the middle of the tightly 
packed consensus aids.
 
Although Marie has managed to survive some horrendous southwesterly 
vertical wind of at least 30 kt, the cyclone is not long for this 
world due to the shear increasing further while the cyclone moves 
over sub-25 deg C sea-surface temperatures for the next few days. 
These very unfavorable environmental conditions should result in all 
convection being stripped away by late Tuesday morning, causing 
Marie to degenerate into a 35-kt post-tropical cyclone. Further 
weakening is anticipated, with Marie becoming a remnant low by 
Tuesday night and dissipating by late Friday or Saturday over the 
far western portion of the eastern Pacific basin.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  06/0900Z 21.7N 134.3W   40 KT  45 MPH
 12H  06/1800Z 22.2N 135.5W   35 KT  40 MPH...POST-TROPICAL
 24H  07/0600Z 22.7N 136.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  07/1800Z 23.0N 137.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  08/0600Z 23.2N 138.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  08/1800Z 23.1N 139.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  09/0600Z 23.2N 140.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  10/0600Z...DISSIPATED
 
$$
Forecaster Stewart
 
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