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Tropical Storm Theta Discussion Number   6
NWS National Hurricane Center Miami FL       AL302020
900 AM GMT Wed Nov 11 2020

Convection associated with Theta has decreased further this 
morning, with strong southwesterly shear displacing the remaining 
convection to the north of the center.  Based on the decreased 
organization, the initial intensity is lowered slightly to 55 kt.

Theta has continued to slow its forward speed, with the initial 
motion now 075/7.  The cyclone is being steered by the southern 
part of the mid-latitude westerlies to the north of a mid-level 
ridge, and this general motion should continue for the next 72 h or 
so.  After that time, the global models suggest that the cyclone 
should shear apart, with the remnant low-level circulation moving 
northeastward on the southeast side of a deep-layer cyclone over 
the northeastern Atlantic.  There has been little change in the 
guidance since the previous advisory, and the new official forecast 
track is similar to the previous track.

While the cyclone is currently experiencing strong shear, the 
global models show that this might diminish somewhat during the 
next 72 h as Theta moves into an area of light winds near an 
upper-level trough axis.  This, combined with sufficient 
instability for deep convection, should allow the storm to change 
little in strength during this time.  After 72 h, strong mid- to 
upper-level northerly flow should cause the system to weaken as the 
convection dissipates and the upper-level portion of the storm is 
pushed off to the south.  The new intensity forecast is lowered a 
bit from the previous forecast, and it lies in the middle of the 
intensity guidance envelope.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  11/0900Z 29.4N  34.7W   55 KT  65 MPH
 12H  11/1800Z 29.9N  33.5W   55 KT  65 MPH
 24H  12/0600Z 30.4N  31.5W   55 KT  65 MPH
 36H  12/1800Z 30.8N  29.1W   50 KT  60 MPH
 48H  13/0600Z 31.3N  26.7W   50 KT  60 MPH
 60H  13/1800Z 31.8N  24.4W   50 KT  60 MPH
 72H  14/0600Z 32.1N  23.1W   50 KT  60 MPH
 96H  15/0600Z 32.5N  21.5W   45 KT  50 MPH
120H  16/0600Z 34.0N  20.0W   35 KT  40 MPH...POST-TROPICAL
 
$$
Forecaster Beven
 
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