CitarREMARKS:
152100Z POSITION NEAR 11.2S 85.8E.
TROPICAL CYCLONE 15S (FIFTEEN), LOCATED APPROXIMATELY 831 NM
EAST-SOUTHEAST OF DIEGO GARCIA, HAS TRACKED WESTWARD AT 04 KNOTS
OVER THE PAST SIX HOURS. RECENT ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS CONSIDERABLE CONSOLIDATION, WITH CONVECTIVE BANDING
WRAPPING INTO A LOW LEVEL CIRCULATION CENTER (LLCC) EVIDENT IN A
151551Z AMSU 89GHZ MICROWAVE SATELLITE IMAGE. INFRARED IMAGERY
FURTHER INDICATES FORMATION OF A LOW- TO MID-LEVEL EYE FEATURE OVER
THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON RECENT
SATELLITE FIXES FROM KNES AND PGTW AND THE AMSU IMAGE. THE INTENSITY
OF 40 KNOTS IS SET ABOVE AGENCY DVORAK ESTIMATES TO ACCOUNT FOR THE
NOTED FORMATIVE EYE FEATURE. UPPER-LEVEL ANALYSIS INDICATES
FAVORABLE CONDITIONS FOR STEADY TO RAPID DEVELOPMENT DUE TO THE
PRESENCE OF STRONG OUTFLOW, LOW VERTICAL WIND SHEAR (5 TO 10 KNOTS)
AND SEA SURFACE TEMPERATURES NEAR 29 CELSIUS. THE SYSTEM IS TRACKING
VERY SLOWLY TO THE WEST IN THE ABSENCE OF A DOMINANT STEERING
MECHANISM, AND IS EXPECTED TO BECOME QUASI-STATIONARY OVER THE NEXT
24 TO 36 HOURS. AFTER TAU 36, A NEAR-EQUATORIAL RIDGE WILL BUILD TO
THE NORTH AND GRADUALLY STEER THE SYSTEM EASTWARD AND POLEWARD
THROUGH TAU 96. IN THE EXTENDED FORECAST PERIOD, TC 15S IS EXPECTED
TO TURN BACK TO THE WEST AS A SUBTROPICAL RIDGE BUILDS POLEWARD OF
THE SYSTEM. DYNAMIC MODEL GUIDANCE IS IN GOOD GENERAL AGREEMENT WITH
THE FORECAST PHILOSOPHY, ALTHOUGH THE GFDN AND COAMPS-TC MODELS
DEPICT OUTLYING EASTWARD TRACKS THROUGH TAU 120. THESE OUTLYING
TRACKS MAY RESULT FROM DEPENDENCE ON THE NAVGEM INITIALIZATION
FIELDS, WHICH DEPICT TC 15S AS ERRONEOUSLY WEAK AND NON-DEVELOPING.
THE REMAINING GUIDANCE, CONSISTING OF THE GFS, GEFS, HWRF, UKMET,
AND ECMWF MODELS, DISAGREE IN THE EXACT TIMING AND DIRECTION OF THE
NEAR-TERM TURN TO THE EAST AND EXTENDED-TERM WESTWARD TURN. THE
CURRENT FORECAST TRACK FAVORS THE GFS, GEFS, HWRF MODEL GROUPING
GIVEN THE ACCURATE ANALYSIS AND REALISTIC DEVELOPMENT PATTERN
DEPICTED IN THESE MODELS. DUE TO NOTED UNCERTAINTY IN THE MODEL
GUIDANCE, THERE IS LOW CONFIDENCE IN THE FORECAST TRACK.