Issued at 500 AM EDT Tue Oct 22 2024
000 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
