WDXS32 PGTW 261500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 22S (GARANCE) WARNING 
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.6S 54.1E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 187 NM NORTH-NORTHWEST OF ST DENIS
   MOVEMENT PAST 6 HOURS: EASTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 21 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
RAPIDLY CONSOLIDATING AND INCREASINGLY MORE SYMMETRICAL CONVECTIVE
STRUCTURE OF TROPICAL CYCLONE (TC) 22S (GARANCE). THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MICROWAVE EYE
PRESENT IN THE 260952Z AMSR2 IMAGE. THE AFOREMENTIONED PASS ALSO 
REVEALS IMPROVING STRUCTURE OF THE SYSTEM, WITH SLIGHT IMPACT OF THE 
MODERATE (15-20 KTS) SOUTHERLY VERTICAL WIND SHEAR (VWS) PRESENT 
THROUGHOUT THE SOUTHERN PORTION OF TC 22S. UPPER LEVEL OUTFLOW IS 
GOOD, WITH STRONG EQUATORWARD AND DEVELOPING POLEWARD COMPONENT. 
COMBINED WITH WARM (28-29 C) SEA SURFACE TEMPERATURES (SST), THE 
ENVIRONMENT CONTINUES TO BE FAVORABLE FOR FURTHER INTENSIFICATION. THE 
INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED 
ON A COMBINATION OF AGENCY DVORAK FIXES AND AUTOMATED ESTIMATES LISTED
BELOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: DEEP-LAYER NEAR EQUATORIAL RIDGE (NER)
TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 61 KTS AT 261200Z
   CIMSS ADT: 61 KTS AT 261200Z
   CIMSS AIDT: 59 KTS AT 261230Z
   CIMSS D-MINT: 70 KTS AT 261220Z
   CIMSS D-PRINT: 69 KTS AT 261130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 22S IS FORECAST TO TRACK EAST-SOUTHEASTWARD
OVER THE NEXT 12 HOURS UNDER THE INFLUENCE OF THE NER TO THE NORTH.
AS THE SYSTEM ROUNDS THE SOUTHERN PERIPHERY OF THE RIDGE, IT WILL
SWIFTLY TURN SOUTHWARD, UNDER THE STEERING GUIDANCE OF A DEVELOPING
SUBTROPICAL RIDGE (STR) TO THE EAST. OVER THE COURSE OF THE
FOLLOWING 48 HOURS, THE NORTH-SOUTH ORIENTED STR WILL REORIENT TO A
MORE HORIZONTAL POSITION. WHILE TC GARANCE TRANSITS SOUTH, IT IS
FORECAST TO TRACK OVER, OR IN TIGHT PROXIMITY OF THE ISLAND OF LA
REUNION. AFTERWARDS, THE SYSTEM IS FORECAST TO ACCELERATE AND BEGIN
TO ROUND THE AXIS OF THE STR BETWEEN TAUS 72 AND 96, FOLLOWED BY AN
EASTWARD TURN COMPLETED BY TAU 120. TC 22S IS FORECAST TO RAPIDLY
INTENSIFY OVER THE NEXT 24-36 HOURS, AS INDICATED BY NEARLY ALL
AVAILABLE RI GUIDANCE, REACHING PEAK INTENSITY OF 100 KTS BETWEEN
TAUS 24 AND 36. SOME GUIDANCE, INCLUDING RI AIDS, DETERMINISTIC
GFS, AS WELL AS HAFS, HINT AT A POTENTIAL FOR REACHING MAXIMUM
INTENSITY AS HIGH AS 110 KTS BETWEEN TAUS 24 AND 36. THIS SUGGESTS THE 
PEAK INTENSIFICATION TO OCCUR JUST BEFORE THE SYSTEM APPROACHES LA
REUNION. AFTER TAU 36, ALL AVAILABLE GUIDANCE INDICATES A QUICK DROP
IN INTENSITY, DRIVEN BY INCREASING VWS, MINOR DRY AIR ENTRAINMENT
FROM THE SOUTH, AS WELL AS COOLING SEA SURFACE TEMPERATURES. BY THE
TIME TC 22S BEGINS TURNING EASTWARD, THE ENVIRONMENTAL CONDITIONS
WILL DEGRADE DRASTICALLY, WITH SST AS LOW AS 22-23 C, AS WELL AS
INCREASING VWS AND MORE DRY AIR ENTERING STRUCTURE OF THE TC FROM THE 
WEST.

MODEL DISCUSSION: THE NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
WITH JUST 85 NM CROSS-TRACK SPREAD AT THE TIME OF PASSING THROUGH
LATITUDE OF 21 DEGREES SOUTH, AROUND TAU 36. ALL MODELS AGREE ON
THE GENERAL STEERING MECHANISM AND TRACK, BUT THE CROSS-TRACK
SPREAD INCREASES TO 260 NM BY TAU 72 LEADING TO A MEDIUM CONFIDENCE
IN THE LONG TERM ASSESSMENT. JTWC TRACK IS LAID CLOSE TO THE
MULTI-MODEL CONSENSUS THROUGHOUT THE FORECAST PERIOD. UNCERTAINTY
INCREASES SIGNIFICANTLY AS THE SYSTEM WEAKENS AND APPROACHES THE
BAROCLINIC ZONE TOWARDS THE END OF THE FORECAST PERIOD. INTENSITY
GUIDANCE IS IN FAIR AGREEMENT THROUGH TAU 120, WITH RIPA AND FRIA
INDICATING 50-60 PERCENT CHANCE OF RI. EC EPS INTENSITY GUIDANCE
BACKED OFF A BIT SINCE LAST RUN, HOWEVER STILL INDICATING 60
PERCENT CHANCE OF MODERATE (10-30 KTS) INTENSIFICATION OVER THE
NEXT 36 HOURS. AFTERWARDS, ALL NUMERICAL MODEL GUIDANCE HINTS AT
RAPID WEAKENING THROUGH TAU 48, FOLLOWED BY A SLOWER AND MORE
STEADY WEAKENING TREND TOWARDS THE END OF THE FORECAST PERIOD.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
NNNN