Tropical Storm Oscar Forecast Discussion

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WTNT41 KNHC 220833
TCDAT1

Tropical Storm Oscar Discussion Number  13
NWS National Hurricane Center Miami FL       AL162024
500 AM EDT Tue Oct 22 2024

Oscar is at best barely a tropical storm at this time.  While
convection associated with the system has increased since the last 
advisory, most of it is occurring in clusters well away from the 
center in the eastern semicircle, and there is only minimal 
convection near the center.  Also, while 850 mb flight-level winds 
were as high as 45-50 kt during an earlier Air Force Reserve 
Hurricane Hunter mission, dropsonde and SFMR data suggests those 
winds were having trouble mixing down to the surface.  The system 
will be maintained as a 35-kt tropical storm pending the next recon 
flight and whether convection will increase further during the 
upcoming diurnal maximum.

The global models are in good agreement that a developing mid- to 
upper-level trough over the southwestern Atlantic will cause 
baroclinic cyclogenesis near or north of Oscar during the next 
24-48 h.  The UKMET shows Oscar become the main focus for the 
development and becoming a large extratropical low, while the GFS 
develops a second low to the north of Oscar with Oscar becoming 
absorbed into the new system.  The ECMWF and Canadian models 
forecast a blend of these scenarios, with the baroclinic low forming 
close to Oscar.  Given Oscar's organization and current trends in 
satellite imagery, the intensity forecast leans towards the GFS 
solution, with Oscar becoming a post-tropical low in less than 24 h 
and then being absorbed by the new low in 36-48 h.  

The initial motion is now 030/10 kt.  Interaction with the above 
mentioned trough should steer Oscar generally northeastward with an 
increase in forward speed until it is absorbed by the new 
baroclinic low.  The new forecast track is similar to the previous 
track.


Key Messages:

1. Through Tuesday, localized flash flooding will be possible across 
the southeastern Bahamas as well as the Turks and Caicos Islands.  
With rainfall easing across Cuba, flooding from rainfall which has 
already occurred could remain a concern for the next several days.

2. Tropical storm conditions are expected in portions of the
southeastern and central Bahamas today.


FORECAST POSITIONS AND MAX WINDS

INIT  22/0900Z 22.7N  74.8W   35 KT  40 MPH
 12H  22/1800Z 23.8N  73.8W   35 KT  40 MPH
 24H  23/0600Z 25.7N  71.7W   35 KT  40 MPH...POST-TROPICAL
 36H  23/1800Z 28.5N  69.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 48H  24/0600Z...DISSIPATED

$$
Forecaster Beven