Atlantic Basin Tropical Cyclones

Tropical Storm Wanda Forecast Discussion


000
WTNT41 KNHC 040233
TCDAT1

Tropical Storm Wanda Discussion Number  17
NWS National Hurricane Center Miami FL       AL212021
300 AM GMT Thu Nov 04 2021

Wanda's convective pattern has waned slightly since this afternoon. 
Earlier there were convective bands noted wrapping around the 
center, but now the primary band only wraps around the southern and 
western portions of the circulation. Subjective and objective Dvorak 
satellite estimates have not changed appreciably since earlier 
today, and recent scatterometer wind data and UW/CIMSS SATCON 
estimates still support an initial intensity of 45 kt. 

Wanda is moving northward or 005/08 kt. The track forecast reasoning 
is unchanged once again. A mid-latitude trough approaching from the 
west should cause Wanda to move northward for another 6-12 hours, 
but after that time the trough is forecast to lift northward. As 
subsequent ridging builds behind the trough, Wanda is expected to 
turn sharply eastward, and then south-southeastward to southward on 
Friday. Another mid-latitude trough moving across Newfoundland by 
the weekend should finally cause Wanda to begin to accelerate 
northeastward after 72 hours. The dynamical model guidance remains 
in relatively good agreement on the evolution of the steering 
pattern over the next several days, and the NHC track forecast is 
near the middle of the guidance envelope. 

Despite Wanda being over 20-21C sea surface temperatures, some 
cooling aloft is forecast over the next couple of days.  That, 
along with generally favorable upper-level winds could allow for 
some slight strengthening within the next day or so.  The global 
models indicate that Wanda will merge with a frontal system on 
Sunday, resulting in the system's transition into an extratropical 
low.  The updated NHC intensity forecast is unchanged from the 
previous advisory and is a blend of the IVCN and HCCA consensus 
aids. 


FORECAST POSITIONS AND MAX WINDS

INIT  04/0300Z 40.6N  39.6W   45 KT  50 MPH
 12H  04/1200Z 41.6N  39.5W   50 KT  60 MPH
 24H  05/0000Z 42.0N  38.8W   50 KT  60 MPH
 36H  05/1200Z 41.0N  37.7W   50 KT  60 MPH
 48H  06/0000Z 39.0N  37.3W   50 KT  60 MPH
 60H  06/1200Z 37.8N  37.4W   45 KT  50 MPH
 72H  07/0000Z 38.1N  36.6W   45 KT  50 MPH
 96H  08/0000Z 44.7N  29.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  09/0000Z 51.0N  20.0W   45 KT  50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Brown



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