WDXS33 PGTW 282100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 23S (HONDE) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.7S 45.0E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 376 NM SOUTHEAST OF TOLIARA, MADAGASCAR
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A SLOW
MOVING SYSTEM JUST OFF THE SOUTHERN TIP OF MADAGASCAR WITH THE
NORTHERN HALF OF ITS COLD DENSE OVERCAST ERODED AND PARTIALLY
EXPOSING THE LOW-LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON THE PARTLY EXPOSED LLC IN THE
EIR LOOP. THE INITIAL INTENSITY OF 70KTS IS BASED ON THE PGTW AND
KNES DVORAK ESTIMATES OF T4.5 AND SUPPORTED BY A 281542Z DIRECT SAR
PASS. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW VWS AND
STRONG OUTFLOW OFFSET BY LOCALIZED COOL SST DUE TO UPWELLING
INDUCED BY THE SLOW STORM MOTION.

INITIAL WIND RADII BASIS: SAR DATA.

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE ESE
OFFSET BY A SECONDARY STR TO THE WSW OVER SOUTH AFRICA. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 54 KTS AT 281636Z
   CIMSS ADT: 33 KTS AT 281500Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC HONDE WILL CONTINUE TO TRACK SLOWLY
SOUTHEASTWARD UNDER THE STEERING INFLUENCE OF THE STR TO THE ESE,
OFFSET BY THE STR TO THE WSW. COOLING ALONG-TRACK SSTS WILL GET
WORSE DUE TO UPWELLING CAUSED BY THE SLOW STORM MOTION.
ADDITIONALLY, COOL DRY AIR IN THE LOW- TO MID-LEVELS WILL BEGIN TO
WRAP FROM THE SOUTHWEST. THIS COMBINED EFFECT WILL RESULT IN A
GRADUAL WEAKENING DOWN TO 60KTS BY TAU 48. AFTER TAU 48, THE STR TO
THE ESE WILL BUILD, ASSUME PRIMARY STEERING, AND DRIVE THE SYSTEM
SOUTHWARD. THE ADDITION OF COOLING SST AND INCREASING VWS WILL
REDUCE THE SYSTEM TO 55KTS BY TAU 120 AND, CONCURRENTLY, WILL BEGIN
EXTRA-TROPICAL TRANSITION AS IT ENTERS THE BAROCLINIC ZONE. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH AN
EVEN AND GRADUAL SPREAD TO 70NM BY TAU 72 AND 81NM BY TAU 120;
HOWEVER, DUE TO UNCERTAINTIES WITH THE INITIAL TO MID PORTION OF THE
STORM MOTION AS A RESULT OF COMPETING STEERING MECHANISMS, THERE IS
ONLY MEDIUM CONFIDENCE IN THE JTWC TRACK AND INTENSITY FORECASTS. 

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