Tropical Depression Thirteen Discussion Number   1
NWS National Hurricane Center Miami FL       AL132024
200 PM CVT Wed Oct 02 2024

The system we have been monitoring several hundred miles to the 
southwest of the southernmost Cabo Verde Islands has become 
gradually better organized this morning with some curved bands 
organizing to the west of the estimated center. Visible satellite 
images show that at least a broad closed circulation has developed. 
Based on the latest subjective Dvorak fixes of T2.5/35-kt from TAFB 
and T1.5/25-kt from SAB, advisories are being initiated on Tropical 
Depression Thirteen, with an initial intensity in between these 
estimates at 30 kt.

The depressions initial motion appears to be slowly due west, at 
270/6 kt. Over the next day or two this motion should continue, 
though some of the track guidance actually shows a south of due west 
motion, partially related to the steering flow and also the 
possibility that the center might try to reform underneath deep 
convective bursts in the southern semicircle. After 48 h, the 
guidance shows TD13 turning west-northwestward and then 
northwestward by the end of the forecast as mid-level ridging 
becomes more eroded on its northwestern side while a large long-wave 
trough becomes established over the Northwest Atlantic. The initial 
NHC track forecast has opted to favor a track close to the consensus 
aid TVCN. Interestingly, both the GFS and ECMWF are on the east side 
of the guidance, while HCCA is on the western side by the end of the 
forecast period. 

Intensity wise, initial strengthening could be on the slower end, as 
the system has to deal with some northwesterly shear related of the 
outflow from the much larger Hurricane Kirk impinging upon the 
system. However, the guidance insists this shear will soon decrease, 
especially after 24-36 h where the upper-level flow seems to split 
off into a cutoff low to the southwest, and a upper-level trough 
that shifts east of the depression, leaving the depression in a more 
favorable upper-level diffluent pattern. After TD13's inner core 
become better defined, the rate of intensification could increase 
after 36 h, and the latest NHC intensity forecast forecasts the 
depression to become a hurricane in 3 days. Additional 
intensification is forecast after that point as long as the cyclone 
tracks far enough away from the cold ocean wake left behind by Kirk. 
This forecast is roughly in the mean of the intensity guidance 
envelope. 


FORECAST POSITIONS AND MAX WINDS

INIT  02/1500Z 10.6N  29.1W   30 KT  35 MPH
12H  03/0000Z 10.5N  29.8W   35 KT  40 MPH
24H  03/1200Z 10.2N  30.8W   40 KT  45 MPH
36H  04/0000Z 10.2N  31.9W   45 KT  50 MPH
48H  04/1200Z 10.4N  33.3W   55 KT  65 MPH
60H  05/0000Z 11.0N  34.6W   60 KT  70 MPH
72H  05/1200Z 11.7N  35.8W   65 KT  75 MPH
96H  06/1200Z 13.5N  38.1W   75 KT  85 MPH
120H  07/1200Z 16.5N  41.0W   80 KT  90 MPH

$$
Forecaster Papin