WDXS31 PGTW 301500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 19S (FYTIA) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.5S 43.0E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 144 NM EAST-SOUTHEAST OF NACALA,
MOZAMBIQUE
   MOVEMENT PAST 6 HOURS: EASTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE 19S (FYTIA) WITH A HIGHLY COMPACT INNER-CORE AND A DEFINED
15 NM EYE. THE SYSTEM IS ANALYZED TO HAVE NEARLY UNDERGONE EXTREME
RAPID INTENSIFICATION AT THIS POINT, INTENSIFYING 50 KTS IN 24
HOURS. 19S HAS ALSO INCREASED TRACK SPEEDS IN THE EASTWARD
DIRECTION, LEAVING THE COMPETING STEERING ENVIRONMENT. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE IN
ANIMATED MSI. THE INITIAL INTENSITY OF 80 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK FIXES AND OBJECTIVE
INTENSITY ESTIMATES LISTED BELOW. ENVIRONMENTAL ANALYSIS INDICATES 
THAT 19S REMAINS IN A HIGHLY FAVORABLE ENVIRONMENT CHARACTERIZED BY 
ROBUST RADIAL OUTFLOW ALOFT, VERY LOW (0-5 KTS) VERTICAL WIND SHEAR, 
AND WARM (29-30 C) SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: PERSISTENCE WITH SLIGHT ADJUSTMENTS BASED
ON THE OBJECTIVE BEST TRACK

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A NEAR EQUATORIAL
RIDGE (NER) POSITIONED TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   FMEE: T4.5 - 77 KTS
   CIMSS SATCON: 79 KTS AT 301100Z
   CIMSS ADT: 82 KTS AT 301200Z
   CIMSS AIDT: 82 KTS AT 301200Z
   CIMSS D-MINT: 83 KTS AT 301041Z
   CIMSS D-PRINT: 80 KTS AT 301200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: INCREASED INTENSITY PRIOR TO LANDFALL

FORECAST DISCUSSION: TC 19S IS FORECAST TO BEGIN TRACKING
SOUTHEASTWARD, ALONG THE SOUTHERN PERIPHERY OF THE NER TO THE NORTH
THROUGH TAU 72. LANDFALL IS CURRENTLY FORECAST TO OCCUR NEAR TAU 12 
CLOSE TO VILAMATSA, MADAGASCAR. 19S WILL THEN TRAVERSE ACROSS CENTRAL 
MADAGASCAR AND EMERGE BACK OVER WATER NEAR TAU 48. 19S IS THEN 
FORECAST TO CONTINUE ON A SOUTHEASTWARD TRACK THROUGH THE REMAINDER OF 
THE FORECAST PERIOD, AS THE NER MERGES WITH A BUILDING STR TO THE
SOUTHEAST. REGARDING INTENSITY, 19S IS FORECAST TO CONTINUE
INTENSIFYING BEFORE MAKING LANDFALL TO A PEAK INTENSITY OF AROUND
90 KTS. 19S HAS EXCEEDED EXPECTATIONS THUS FAR, SO IT MAY PEAK EVEN
HIGHER THAN CURRENTLY FORECAST. THE SYSTEM WILL THEN RAPIDLY WEAKEN
THROUGH TAU 36 AS IT CROSSES MADAGASCAR DUE TO RUGGED TERRAIN
INTERACTION. A REINTENSIFICATION PHASE IS EXPECTED TO ENSUE AFTER TAU 
48 AS THE ENVIRONMENT BECOMES MORE FAVORABLE DUE TO THE SYSTEM TAPPING 
INTO WARM SEA SURFACE TEMPERATURES ONCE AGAIN. HOWEVER, NORTHWESTERLY
SHEAR IS FORECAST TO INCREASE TO OVER 20 KTS NEAR AROUND TAU 72,
DISALLOWING A SECOND BOUT OF RI. AN INTENSITY OF AROUND 65 KTS IS
FORECAST FOR THE END OF THE FORECAST PERIOD. 19S IS FORECAST TO
BEGIN SUBTROPICAL TRANSITION AT AROUND TAU 120 AS IT STARTS TO
INTERACT WITH THE NORTHERN EXTENT OF THE STRONG UPPER-LEVEL 
WESTERLIES.  

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT WITH THE EXCEPTION OF NAVGEM, WHICH TRACKS THE SYSTEM
SIGNIFICANTLY FURTHER EQUATORWARD THAN THE REMAINDER OF GUIDANCE.
DISCOUNTING NAVGEM, THERE IS A MERE 80 NM CROSS-TRACK SPREAD AT TAU
72, WHICH ONLY SLIGHTLY INCREASES TO 90 NM AT TAU 120. HOWEVER,
ALONG-TRACK SPREAD INCREASES QUITE A BIT AFTER TAU 72, TO AROUND
200 NM AT TAU 120. THE GDM ENSEMBLE MEAN IS THE FASTEST MODEL WHILE
THE GFS IS THE SLOWEST. THE JTWC TRACK FORECAST IS PLACED CLOSE TO
THE MULTI-MODEL CONSENSUS WITH OVERALL MEDIUM CONFIDENCE DUE TO
INHERENT UNCERTAINTIES REGARDING THE LAND INTERACTION WITH
MADAGASCAR. INTENSITY GUIDANCE REMAINS IN POOR AGREEMENT. RELIABLE
INTENSITY GUIDANCE REMAINS SIGNIFICANTLY LOWER THAN WHAT REALITY
CURRENTLY DEPICTS. TO MAKE MATTERS WORSE, HAFS-A AND HWRF BOTH TAKE
THE SYSTEM OVER LAND QUICKER THAN WHAT THE CONSENSUS TRACKER DOES,
ADDING FURTHER UNCERTAINTY IN THE PEAK INTENSITY PRIOR TO LANDFALL.
THE JTWC INTENSITY FORECAST GOES AGAINST NEARLY ALL AVAILABLE
GUIDANCE AND CALLS FOR A PEAK OF AROUND 90 KTS AT TAU 12. MODELS
THEN GENERALLY AGREE ON RAPID WEAKENING THROUGH TAU 36 AND THEN
REINTENSIFICATION THROUGH TAU 120. THE JTWC INTENSITY FORECAST
FOLLOWS MORE CLOSELY TO HWRF AND COAMPS-TC FROM TAU 48 ONWARD, AND
CALLS FOR AN INTENSITY OF AROUND 65 KTS NEAR THE END OF THE
FORECAST PERIOD. 

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