WDXS31 PGTW 010300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 19S (FYTIA) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.8S 48.3E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 46 NM EAST OF ANTANANARIVO, MADAGASCAR
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: XX FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 19S (FYTIA) HAS TRUDGED ACROSS MADAGASCAR
OVER THE PAST SIX HOURS STRUGGLING TO MAINTAIN SOME RESEMBLANCE OF
STRUCTURE WHILE CROSSING THE MORE MOUNTAINOUS REGIONS OF THE
COUNTRY AS DEPICTED BY ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY. TERRAIN HAS CAUSED THE SYSTEM TO BECOME MISALIGNED WITH
THE LOW LEVEL CIRCULATION CENTER (LLCC) OVER LAND AND SOME DEEP
CONVECTION DISPLACED TO THE EAST. THE INITIAL POSITION IS PLACED
WITH MEDIUM CONFIDENCE BASED ON ANIMATED EIR IMAGERY OF THE
OBSCURED LLCC AND LOCAL WIND OBSERVATIONS FROM ANTANANARIVO IVATO
AND TOAMASINA. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH LOW
CONFIDENCE BASED ON STATISTICAL-DYNAMICAL MODEL
GUIDANCE.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE (NER) CENTERED TO
THE NORTH-NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   CIMSS D-MINT: 31 KTS AT 312222Z
   CIMSS D-PRINT: 40 KTS AT 310100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: LOW
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TROPICAL CYCLONE FYTIA WILL CONTINUE TRACKING
TO THE SOUTHEAST UNDER THE INFLUENCE OF THE NEAR EQUATORIAL RIDGE
TO THE NORTH-NORTHEAST UNTIL A HANDOFF BETWEEN STEERING MECHANISMS
AROUND TAU 24 WHICH WILL ALLOW THE SYSTEM TO PROGRESS FURTHER
SOUTHEAST. THE CIRCULATION IS EXPECTED TO MEND ITS CURRENT
STRUCTURE, INTENSIFYING TO WIND SPEEDS OF APPROXIMATELY 45 KTS BY
TAU 24 AND A MAXIMUM FORECASTED STRENGTH OF 55 KTS BY TAU 72.
DETERMINISTIC AND ENSEMBLE MODELS HAVE HIGH HOPES FOR THE SYSTEM
THOUGH IT IS LIKELY THAT THE VERTICAL WIND SHEAR AND AVAILABLE
MOISTURE AFTER ENTERING THE INDIAN OCEAN ARE SLIGHTLY
MISREPRESENTED IN THE GUIDANCE OPENING UP THE POSSIBILITY OF A
STEADY WEAKENING TREND VICE HOLDING STEADY IN THE 50 KT TO 55 KT
RANGE. BETWEEN TAU 96 AND 120 A SUDDEN DROP IN SEA SURFACE
TEMPERATURES WILL BE ADDED TO THE LIST OF HINDERING CONDITIONS FOR
TC FYTIA RESULTING IN A QUICK TRANSITION INTO A SUBTROPICAL SYSTEM
BY TAU 120. 

MODEL DISCUSSION: CROSS TRACK MODEL GUIDANCE IS UNDER 40 NM TILL
TAU 48. AFTERWARDS THE SPREAD INCREASES UPWARDS OF 100 NM AS THE
MODELS DISAGREE ON HOW MUCH FURTHER SOUTHEAST THE SUBTROPICAL RIDGE
WILL BE ABLE TO PUSH THE SYSTEM. NAVGEM IS QUICK TO PULL THE
CIRCULATION FURTHER SOUTH WHILE MAJORITY OF THE REMAINING CONSENSUS
MEMBERS KEEP A STEADIER TRACK TOWARDS THE SOUTHEAST. THE JTWC
FORECAST TRACK IS PLACED CLOSE TO THE MULTI MODEL CONSENSUS WITH
MEDIUM CONFIDENCE FOR THE FIRST 72 HOURS AND LOW CONFIDENCE FOR THE
REMAINDER OF THE FORECAST. INTENSITY GUIDANCE IS SPREAD UP TO 40
KTS WITH GFS GIVING STEADIER AND MORE CONSERVATIVE GUIDANCE WHILE
COAMPS-TC AND HAFS-A DEPICT A MAXIMUM INTENSITY AROUND 65 KTS. THE
JTWC FORECAST REFLECTS INTENSITIES IN LINE WITH THE MULTI MODEL
CONSENSUS FAVORING THE LOWER INTENSITIES CONSISTENT WITH EXPECTED
ENVIRONMENTAL CONDITIONS.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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