701. Tropical Storm 13S » Text Products

• STORM FLOATER •

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PUBLIC ADVISORY #
FORCE THIRTEEN , 

    
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SUMMARY OF INFORMATION
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LOCATION...NEAR    ...
MAXIMUM SUSTAINED WINDS...MPH...KM/H
MINIMUM CENTRAL PRESSURE...MB
    
WATCHES AND WARNINGS
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...CYCLONE WARNING...
Cocos Island

For related warnings, please refer to the Bureau of Meteorology for latest warnings.

DISCUSSION
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Position accuracy has improved in visible images before sunset as the low level
centre became exposed again from the CDO. Intensity based on observations from
Cocos Island located 35nm to the northwest and recent scatsat scatterometer pass
at 21/0130 UTC.

Tropical low 10U has shown a weakening trend over the last 6 hours with deep
convection over the low level centre being sheared off to the west. In the last
2 hours, another pulse of deep convection has developed on the western side.
Dvorak assessment based on FT=PT=1.5. CI was held at 2.5 due to inital weakening
but reintensification is expected as the system moves into the diurnally
favourable period.

10U is in an area of moderate vertical wind shear on the northern side of the
upper ridge, under a divergent easterly flow of around 10-20kt at 200hPa. 

Model guidance indicates a slight decrease in the upper winds over the next 24
hours, although moderate shear is still expected. A mid level ridge developing
over southern Java and to the east of 10U is expected to slowly steer the system
towards the southwest tonight and on Friday, aided by a mid level trough further
south over the Indian Ocean. Consequently, increased poleward outflow will
slightly intensify the system in the short term. 10U is expected to continue
moving southwards on the perphery of the mid level ridge to the east over the
next 2 to 3 days. The system is expected to start tracking towards the southwest
later in the weekend or early next week as a ridge to the southwest of 10U in
the southwest Indian Ocean weakens. Sea surface temperatures remain favourable
on 10U's current track. However, mid level dry air in the longer term may
inhibit its development potential.

10U is expected to reach tropical cyclone intensity as gales are forecast to
extend more than half way around the low level centre later tonight or tomorrow.

LOCAL AND OFFICIAL SOURCES BELOW
Bureau of Meteorology
    

    
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Forecaster

• OFFICIAL JTWC FORECAST •
• BUREAU OF METEOROLOGY, PERTH FORECAST •