Tropical Storm Oscar Forecast Discussion

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WTNT41 KNHC 212042
TCDAT1

Tropical Storm Oscar Discussion Number  11
NWS National Hurricane Center Miami FL       AL162024
500 PM EDT Mon Oct 21 2024

Although the circulation of Oscar is rather broad, visible 
satellite images show that the center is nearing the northern coast 
of eastern Cuba.  Deep convection associated with the system has 
diminished during the day, at least partially due to a diurnal 
fluctuation.  The intensity is kept, perhaps generously, at 35 kt 
for this advisory.  Surface synoptic observations and earlier 
scatterometer data indicate that the strongest winds are over the 
eastern semicircle of the cyclone, and no tropical-storm-force 
wind radii are shown to the northwest or southwest of the center 
for this advisory.

Oscar been turning fairly sharply to the right while the system 
executes a hairpin turn over eastern Cuba.  The current motion 
estimate is around 330/6 kt.  The tropical cyclone is expected to 
turn northward and northeastward with some increase in forward 
speed while it moves on the southeastern and eastern side of a 
mid-level trough.  Since the system has moved a little farther west 
than previously estimated, the overall official track forecast has 
been shifted slightly west of the previous one.  This is a blend of 
the simple and corrected dynamical model consensus predictions.

The tropical cyclone should move back over water soon, so some 
restrengthening is possible during the next day or two.  However, 
Oscar will be moving into an area of strong upper-level winds over 
the next couple of days which should impart significant westerly 
shear over the system.  Also, the cyclone is expected to remain in 
a relatively dry air mass to the north of the Greater Antilles.  
Thus, only slight restrengthening seems possible.  The official 
intensity forecast is above the latest SHIPS and LGEM guidance.  
In 2 to 3 days, the global models show the system being absorbed by 
a non-tropical low pressure system to the west of Bermuda.

The primary hazard associated with Oscar will continue to be heavy
rainfall and life-threatening flash flooding, particularly over the
mountainous terrain of eastern Cuba.  Over the last 24 hours, a 
rainfall total of nearly 15 inches was reported at Punta de Maisi 
on the eastern tip of Cuba.


Key Messages:

1. Through midweek, heavy rainfall from Oscar will lead to areas of
significant, life-threatening flash flooding along with mudslides
across portions of eastern Cuba, especially within the Sierra
Maestra. In addition, localized flash flooding will be possible
across the southeastern Bahamas.

2. Tropical storm conditions are expected to continue into this 
evening across portions of eastern Cuba. Tropical storm conditions 
are also expected in portions of the southeastern and central 
Bahamas tonight and Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT  21/2100Z 21.0N  76.1W   35 KT  40 MPH...INLAND
 12H  22/0600Z 21.8N  75.4W   35 KT  40 MPH...OVER WATER
 24H  22/1800Z 23.3N  74.1W   40 KT  45 MPH
 36H  23/0600Z 25.0N  72.4W   40 KT  45 MPH
 48H  23/1800Z 27.4N  70.2W   40 KT  45 MPH
 60H  24/0600Z 31.5N  67.4W   40 KT  45 MPH
 72H  24/1800Z...ABSORBED BY NON-TROPICAL LOW PRESSURE AREA

$$
Forecaster Pasch/Delgado