Atlantic Basin Tropical Cyclones

Subtropical Storm Teresa Forecast Discussion


000
WTNT44 KNHC 250242
TCDAT4

Subtropical Storm Teresa Discussion Number   2
NWS National Hurricane Center Miami FL       AL192021
1100 PM AST Fri Sep 24 2021

Teresa's cloud pattern is not well organized, even for a 
subtropical cyclone.  The main convective band is rather ragged in 
appearance, and situated 100 n mi or more to the east and northeast 
of the exposed low-level center.  The current intensity estimate, 
40 kt, is in general agreement with the latest subtropical 
satellite classification from TAFB, but given the disheveled 
appearance of the system, this may be generous.

Teresa has recently been moving more westward than northward, on 
the northern side of a mid-level cyclonic circulation, and the 
current motion estimate is an uncertain 300/9 kt.  During the 
next day or so, the cyclone is likely to turn northward and 
northeastward ahead of a mid-tropospheric trough that will 
be moving over the northeastern United States and Atlantic 
Canada.  The official forecast is a little faster than the previous 
one, but along the same general trajectory.  The HCCA model 
consensus is somewhat faster than the NHC prediction.

The cyclone has been situated under an upper-level low which has 
kept the vertical shear fairly low thus far.  However, as this low 
moves away from the area, Teresa will begin to experience 
increasing west-southwesterly shear, and no strengthening is 
expected.  In 48 hours or so, based on the global models, the storm 
is forecast to become absorbed by the aforementioned trough.


FORECAST POSITIONS AND MAX WINDS

INIT  25/0300Z 34.3N  65.4W   40 KT  45 MPH
 12H  25/1200Z 35.2N  65.5W   40 KT  45 MPH
 24H  26/0000Z 36.2N  64.9W   40 KT  45 MPH
 36H  26/1200Z 37.8N  64.0W   40 KT  45 MPH
 48H  27/0000Z...ABSORBED

$$
Forecaster Pasch



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