Current Southern Hemisphere Tropical Systems: Tropical Cyclone 13S Felleng

301500Z POSITION NEAR 16.5S 52.4E.
TROPICAL CYCLONE (TC) 13S (FELLENG), LOCATED APPROXIMATELY 330 NM
NORTH-NORTHWEST OF LA REUNION, HAS TRACKED SOUTH-SOUTHWESTWARD AT 13
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY SHOWS THE SYSTEM HAS FURTHER DEEPENED WITH CONVECTIVE BANDS
WRAPPING TIGHTER INTO A SYMMETRICAL 20-NM EYE. THE SAME ANIMATION 
ALSO SHOWS A POLEWARD CHANNEL HAS EMERGED ALONG THE SOUTHEASTERN
PERIPHERY, COMPLEMENTING AN ALREADY ROBUST EQUATORWARD OUTFLOW. THE
INITIAL POSITION IS FIXED WITH HIGH CONFIDENCE ON THE EYE FEATURE IN
THE ABOVE ANIMATION. THE INITIAL INTENSITY IS SUPPORTED BY CONGRUENT
DVORAK ESTIMATES FROM PGTW AND KNES. UPPER LEVEL ANALYSIS INDICATES
THE SYSTEM IS IN THE VICINITY OF A POINT SOURCE ANTICYCLONE IN AN
AREA OF LIGHT TO MODERATE (10-15 KNOT) VERTICAL WIND SHEAR (VWS). THE
CYCLONE IS TRACKING ALONG THE NORTHWEST EXTENSION OF A DEEP-LAYERED
SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST THAT HAS BEGUN TO RECEDE IN
RESPONSE TO A MID-LATITUDE TROUGH APPROACHING FROM THE WEST AND
CURRENTLY DIGGING THE WESTERN EXTENT OF THE STR AND CAUSING TC 13S TO
TRACK MORE POLEWARD. THE SYSTEM IS FORECAST TO FURTHER INTENSIFY OVER
THE NEXT 24 HOURS DUE TO THE CONTINUED FAVORABLE UPPER LEVEL
ENVIRONMENT, ENHANCED BY THE OPENING OF A POLEWARD OUTFLOW CHANNEL.
AFTER TAU 24, TC FELLENG WILL GRADUALLY WEAKEN AS VWS INCREASES AND
SEA SURFACE TEMPERATURES BEGIN TO COOL. THE AVAILABLE NUMERIC
GUIDANCE REMAINS IN TIGHT AGREEMENT WITH THE SOLE EXCEPTION OF WBAR
THAT CONTINUES TO DEFLECT THE VORTEX TO THE RIGHT OF THE MODEL
ENVELOPE. THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST WHICH
IS LAID JUST TO THE LEFT OF CONSENSUS TO OFFSET WBAR. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 301200Z IS 38 FEET.

- JTWC + CIMSS