Hurricane Oscar Forecast Discussion Number 5

Issued at 500 AM EDT Sun Oct 20 2024 000 WTNT41 KNHC 200844 TCDAT1 Hurricane Oscar Discussion Number 5 NWS National Hurricane Center Miami FL AL162024 500 AM EDT Sun Oct 20 2024 Animation of 1-minute GOES infrared satellite images indicates that Oscar's center has made landfall on the eastern side of Great Inagua Island in the southeastern Bahamas. Small convective bursts have occasionally been noted close to the center during the overnight hours, suggesting that the hurricane still has a very tight inner core. Overall, the satellite presentation is not quite as well organized as it was yesterday afternoon, and with the small core now over Great Inagua, the estimated intensity is lowered slightly to 70 kt--albeit with a very large error bar. An Air Force Reserve Hurricane Hunter mission is scheduled to investigate Oscar in a few hours. Oscar is moving south of due west (260 degrees), still at about 10 kt. Due to strong mid-level ridging to the north and west, Oscar is forecast to turn west-southwestward this morning, which will bring the center to the coast of northeastern Cuba later this afternoon. The ridge is expected to be replaced by a developing mid- to upper-level trough over the western Atlantic in 24-48 hours, which should cause Oscar to turn westward and then northward while inland over Cuba on Monday. Oscar is then forecast to accelerate northeastward over the central Bahamas on Tuesday ahead of the trough. The NHC track forecast is very close to the HCCA consensus aid for the first 36 hours of the forecast, and then more closely follows a blend of HCCA with TVCA after that time. This forecast is not too different from the previous prediction. Oscar's small size will continue to make it susceptible to intensity fluctuations, but the cyclone is expected to reach northeastern Cuba as a hurricane later this afternoon. That small size will also make the core vulnerable to being heavily disrupted by the terrain of eastern Cuba, which rises several thousand feet above sea level. Because of this, the GFS and ECMWF global fields in particular show Oscar's circulation becoming less compact and less well defined in about 36 hours. Oscar is forecast to weaken over Cuba, but it could still be a tropical storm when it emerges back over the Atlantic and moves across the central Bahamas in 2-3 days. Alternatively, it's also possible the Oscar could degenerate into a remnant low or dissipate entirely while over eastern Cuba. If Oscar does survive Cuba, it is likely to be absorbed by a larger non-tropical area of low pressure over the western Atlantic, and the new NHC forecast therefore shows dissipation by day 4. Key Messages: 1. A Hurricane Warning remains in effect for the southeastern Bahamas and for a portion of the northeastern coast of Cuba. 2. Oscar is expected to produce a dangerous storm surge on portions of the southeastern Bahamas this morning, especially Great Inagua Island, and along the north shore of Cuba later this afternoon and evening. 3. Heavy rainfall from Oscar will lead to areas of flash flooding along with possible mudslides across portions of eastern Cuba, especially within the Sierra Maestra, through Tuesday. FORECAST POSITIONS AND MAX WINDS INIT 20/0900Z 21.1N 73.1W 70 KT 80 MPH 12H 20/1800Z 20.6N 74.3W 70 KT 80 MPH 24H 21/0600Z 20.4N 75.4W 50 KT 60 MPH...INLAND 36H 21/1800Z 20.8N 76.1W 40 KT 45 MPH...INLAND 48H 22/0600Z 21.7N 76.0W 40 KT 45 MPH...OVER WATER 60H 22/1800Z 22.7N 75.2W 35 KT 40 MPH 72H 23/0600Z 23.8N 74.0W 35 KT 40 MPH 96H 24/0600Z...DISSIPATED $$ Forecaster Berg

Oct 20, 2024 - 08:00
Hurricane Oscar Forecast Discussion Number 5
Issued at 500 AM EDT Sun Oct 20 2024

000
WTNT41 KNHC 200844
TCDAT1
 
Hurricane Oscar Discussion Number   5
NWS National Hurricane Center Miami FL       AL162024
500 AM EDT Sun Oct 20 2024
 
Animation of 1-minute GOES infrared satellite images indicates that 
Oscar's center has made landfall on the eastern side of Great 
Inagua Island in the southeastern Bahamas.  Small convective bursts 
have occasionally been noted close to the center during the 
overnight hours, suggesting that the hurricane still has a very 
tight inner core.  Overall, the satellite presentation is not quite 
as well organized as it was yesterday afternoon, and with the 
small core now over Great Inagua, the estimated intensity is lowered 
slightly to 70 kt--albeit with a very large error bar.  An Air Force 
Reserve Hurricane Hunter mission is scheduled to investigate Oscar 
in a few hours.

Oscar is moving south of due west (260 degrees), still at about 10 
kt.  Due to strong mid-level ridging to the north and west, Oscar 
is forecast to turn west-southwestward this morning, which will 
bring the center to the coast of northeastern Cuba later this 
afternoon.  The ridge is expected to be replaced by a developing 
mid- to upper-level trough over the western Atlantic in 24-48 
hours, which should cause Oscar to turn westward and then northward 
while inland over Cuba on Monday.  Oscar is then forecast to 
accelerate northeastward over the central Bahamas on Tuesday ahead 
of the trough.  The NHC track forecast is very close to the HCCA 
consensus aid for the first 36 hours of the forecast, and then more 
closely follows a blend of HCCA with TVCA after that time.  This 
forecast is not too different from the previous prediction.

Oscar's small size will continue to make it susceptible to 
intensity fluctuations, but the cyclone is expected to reach 
northeastern Cuba as a hurricane later this afternoon.  That small 
size will also make the core vulnerable to being heavily disrupted 
by the terrain of eastern Cuba, which rises several thousand feet 
above sea level.  Because of this, the GFS and ECMWF global fields 
in particular show Oscar's circulation becoming less compact and 
less well defined in about 36 hours.  Oscar is forecast to weaken 
over Cuba, but it could still be a tropical storm when it emerges 
back over the Atlantic and moves across the central Bahamas in 2-3 
days.  Alternatively, it's also possible the Oscar could 
degenerate into a remnant low or dissipate entirely while over 
eastern Cuba.  If Oscar does survive Cuba, it is likely to be 
absorbed by a larger non-tropical area of low pressure over the 
western Atlantic, and the new NHC forecast therefore shows 
dissipation by day 4.
 
 
Key Messages:

1. A Hurricane Warning remains in effect for the southeastern 
Bahamas and for a portion of the northeastern coast of Cuba.
 
2. Oscar is expected to produce a dangerous storm surge on portions
of the southeastern Bahamas this morning, especially Great Inagua 
Island, and along the north shore of Cuba later this afternoon and 
evening.
 
3. Heavy rainfall from Oscar will lead to areas of flash flooding 
along with possible mudslides across portions of eastern Cuba, 
especially within the Sierra Maestra, through Tuesday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0900Z 21.1N  73.1W   70 KT  80 MPH
 12H  20/1800Z 20.6N  74.3W   70 KT  80 MPH
 24H  21/0600Z 20.4N  75.4W   50 KT  60 MPH...INLAND
 36H  21/1800Z 20.8N  76.1W   40 KT  45 MPH...INLAND
 48H  22/0600Z 21.7N  76.0W   40 KT  45 MPH...OVER WATER
 60H  22/1800Z 22.7N  75.2W   35 KT  40 MPH
 72H  23/0600Z 23.8N  74.0W   35 KT  40 MPH
 96H  24/0600Z...DISSIPATED
 
$$
Forecaster Berg