Hurricane Oscar Forecast Discussion

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WTNT41 KNHC 200844
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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