WDXS33 PGTW 030900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 23S (HONDE) WARNING NR 
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.3S 46.8E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 472 NM SOUTHEAST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A NEARLY FULLY 
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) OF THE TROPICAL CYCLONE 
(TC) 23S (HONDE), WITH MAJORITY OF THE DEEP CONVECTION BEING SHEARED 
OFF TO THE SOUTHEAST. THE SYSTEM IS STRUGGLING WITH PRODUCING 
PERSISTENT AND WIDESPREAD CONVECTION DUE TO STRONG DRY AIR ENTRAINMENT
ORIGINATING FROM THE AIR MASS TO THE WEST. ON THE OTHER HAND,
POLEWARD OUTFLOW REMAINS STRONG AND SUPPORTIVE, TOGETHER WITH WARM
(26-27 C) SEA SURFACE TEMPERATURES (SST). THE SYSTEM IS VERY SLOWLY
BEGINNING TO TRANSIT SOUTHEASTWARD AFTER A PERIOD OF SIGNIFICANT 
TRANSLATION SPEED SLOW DOWN. THE INITIAL POSITION IS PLACED WITH HIGH 
CONFIDENCE BASED ON THE CONVECTIVE BANDING WRAP PRESENT IN THE 030446Z 
GMI 37 GHZ MICROWAVE IMAGE. THE INITIAL INTENSITY OF 55 KTS IS 
ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK AND 
OBJECTIVE INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T2.5 - 35 KTS
   DEMS: T3.5 - 55 KTS
   CIMSS SATCON: 50 KTS AT 030308Z
   CIMSS ADT: 53 KTS AT 030300Z
   CIMSS AIDT: 50 KTS AT 030500Z
   CIMSS D-MINT: 38 KTS AT 030443Z
   CIMSS D-PRINT: 36 KTS AT 030500Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 5-10 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: CONTINUOUS DRY AIR ENTRAINMENT FROM THE WEST

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 23S IS FORECAST TO BEGIN ACCELERATING
SOUTH-SOUTHEASTWARD UNDER THE PRIMARY INFLUENCE OF THE STR TO THE
EAST THROUGHOUT THE FORECAST PERIOD. BY TAU 48, THE SYSTEM WILL
APPROACH THE TAIL END OF THE UPPER-LEVEL JET AND BEGIN TO INTERACT
WITH THE BAROCLINIC ZONE. BY TAU 72 IT IS FORECAST TO COMPLETE THE
EXTRATROPICAL TRANSITION, WHILE MAKING AN EASTWARD TURN AHEAD OF A
LONGWAVE TROUGH AND ANOTHER UPPER-LEVEL JET MAXIMA. TC HONDE IS 
FORECAST TO MAINTAIN INTENSITY THROUGHOUT ITS TROPICAL CYCLONE PHASE, 
AND START WEAKENING AS SOON AS IT BEGINS THE EXTRATROPICAL TRANSITION.
DUE TO COOLING SST, INCREASING VERTICAL WIND SHEAR AND DRY AIR
ERODING THE STRUCTURE OF THE SYSTEM, TC 23S IS FORECAST TO WEAKEN
DOWN TO 40 KTS, AS IT BECOMES A COLD-CORE LOW.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE REMAINS IN GOOD
AGREEMENT THROUGHOUT THE FORECAST PERIOD WITH ALL MODELS TIGHTLY
PACKED WITHIN A 22 NM CROSS-TRACK SPREAD AT TAU 24, EXTENDING OUT
TO JUST 75 NM AT TAU 72. JTWC TRACK FORECAST IS THEREFORE PLACED
WITH HIGH CONFIDENCE, CLOSE TO THE MULTI-MODEL CONSENSUS. INTENSITY
GUIDANCE IS IN SIMILARLY GOOD AGREEMENT, WITH MAJORITY OF THE MEMBERS
SUGGESTING A NEARLY CONSTANT INTENSITY THROUGH TAU 36, FOLLOWED BY
A STEADY WEAKENING TREND. THE ONLY OUTLIER IN THE MULTI-MODEL
CONSENSUS GROUP IS HWRF, WHICH PREDICTS THE SYSTEM TO INTENSIFY TO
60-65 KTS BY TAU 24, FOLLOWED BY RAPID WEAKENING.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
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