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Tropical Cyclone Narelle (08S) Tracking Southward – January 14th, 2013

21.2S 111.7E

January 14th, 2013 Category: Tropical Storms

Tropical Storm 08S – January 13th, 2013

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Track of Tropical Storm 08S - January 13th, 2013 © Univ. of Wisconsin

Track of TS 08S

Tropical Cyclone Narelle (08S), located approximately 310 nm southwest of Learmonth, Australia, has tracked southward at 11 knots over the past six hours. Maximum significant wave height is 24 feet.

Animated multispectral satellite imagery (MSI) depicts a rapidly decaying system with stratocumulus clouds beginning to wrap around and only shallow convection left obscuring a defined low level circulation center. An SSMIS image concurs with the MSI and is beginning to show dry air wrapping into the system from the south. There is good confidence in the initial position based on the aforementioned imagery.

The initial intensity is assessed at 55 knots based on Dvorak current intensity estimates of 55 knots from PGTW and APRF. Narelle is forecast to track south- southwestward along the western periphery of the subtropical ridge through TAU 12. After TAU 12, the system will recurve southeastward in response to a deep midlatitude shortwave trough.

TC 08S is expected to weaken rapidly as it tracks over cool sea surface temperatures (SSTs) and will also begin extra-tropical transition (ETT) by TAU 24 and is expected to complete ETT by TAU 36. Dynamic model guidance is in tight agreement through the forecast period, lending to high confidence in the JTWC forecast track. There is a possibility that the system will weaken below 35 knots before completing ETT due to the cold SSTs and strong vertical wind shear.

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