Hurricane Oscar Forecast Discussion

767 
WTNT41 KNHC 201459
TCDAT1

Hurricane Oscar Discussion Number   6
NWS National Hurricane Center Miami FL       AL162024
1100 AM EDT Sun Oct 20 2024

Oscar remains a compact hurricane as it nears its next landfall in 
the northeastern coast of Cuba. The Air Force Reserve 
Reconnaissance has been performing another resources permitting 
mission, finding that Oscar remains a small hurricane, though the 
last several fixes do indicate the eye is a bit larger than 
observed yesterday, with a 15-20 mile wide eye. This eye feature is 
also being occasionally observed on radar imagery from Guantanamo 
Bay. On satellite, Oscar still remains well organized with a small 
central dense overcast with very cold cloud tops below -80 C. In 
fact, the subjective and objective intensity estimates based on 
satellite are quite a bit higher than yesterday at this time. From 
the aircraft in-situ data, a blend of the flight level, SFMR, and 
dropsonde data still supports a current intensity of 70 kt this 
advisory.

Oscar has made its turn to the west-southwest, with the current 
estimated motion from recon fixes at 250/7 kt. The narrow mid-level 
ridge that was originally north of Oscar has shifted westward while 
a weakness develops farther east from a mid-latitude trough, and 
that has resulted in the steering over the hurricane shifting more 
equatorward, allowing the west-southwestward motion. However, the 
trough's weakness will continue to grow and also migrate westward, 
and Oscar still seems likely to slow to a crawl after it moves 
inland over Cuba. Ultimately Oscar is still expected to reemerge 
into the southwestern Atlantic in 36 h and migrate northeastward as 
it becomes captured by the deep-layer trough.  The NHC track 
forecast remains close to the HCCA and TVCA consensus aids, and is 
quite similar to the prior track forecast.

Oscar appears to be holding its own today, and not much change in 
intensity is expected before it reaches the northeastern Cuba coast 
this afternoon as a hurricane. There is high terrain in eastern Cuba 
that is likely to severely disrupt the small inner-core of Oscar 
after it moves inland. Some of the global model guidance (especially 
the GFS) shows that Oscar could weaken more over than shown here. 
Assuming Oscar survives its passage over Cuba, the NHC forecast 
shows it emerging back offshore as a tropical storm in 36-48 h. 
Environmental conditions will be quite unfavorable for additional 
tropical development by that time, with increasing northwesterly 
shear and very dry mid-level air. Ultimately Oscar will finally be 
absorbed by a larger deep-layer baroclinic trough over the western 
Atlantic after 72 h, similar to the prior forecast. 


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 Wednesday.  In 
addition, localized flash flooding will be possible across the 
southeastern Bahamas through Wednesday.


FORECAST POSITIONS AND MAX WINDS

INIT  20/1500Z 20.7N  73.9W   70 KT  80 MPH
 12H  21/0000Z 20.4N  74.8W   65 KT  75 MPH...INLAND
 24H  21/1200Z 20.5N  75.6W   45 KT  50 MPH...INLAND
 36H  22/0000Z 21.1N  76.0W   40 KT  45 MPH...OVER WATER
 48H  22/1200Z 22.1N  75.7W   40 KT  45 MPH
 60H  23/0000Z 23.0N  75.0W   40 KT  45 MPH
 72H  23/1200Z 24.0N  73.7W   35 KT  40 MPH
 96H  24/1200Z...DISSIPATED

$$
Forecaster Papin