WDXS31 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 04S (CHIDO) WARNING NR 
011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.9S 47.6E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 579 NM EAST-SOUTHEAST OF DAR ES SALAAM,
TANZANIA
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
THE EYE OF CHIDO (TC 04S) HAS FILLED AND TOPS AROUND THE SYSTEM
HAVE WARMED SUBSTANTIALLY DURING THE PAST 8 HOURS BUT A 131629Z
TROPICS SERIES REVEALS THAT A CLEARLY DISCERNABLE MICROWAVE EYE 
PERSISTS BELOW THE CANOPY. THE MICROWAVE EYE SUPPORTS THE AGENCY 
DVORAKS FROM JTWC, LA REUNION, AND NESDIS, WHICH ARE UNANIMOUS WITH 
CIS OF T5.0. THE INTENSITY ASSESSMENT IS BASED ON THE DVORAKS AS THE 
EAGERLY ANTICIPATED SAR IMAGERY IS ARRIVING FASHIONABLY LATE AND WILL 
NOT BE A FACTOR UNTIL THE 0000Z CYCLE. THE SHORT TERM WEAKENING IS
UNDERSTANDABLE GIVEN IT HAS TRACKED THROUGH A REGION OF SLIGHTLY
LOWER SEA SURFACE TEMPERATURES AND UNDERGONE SOME LAND INTERACTION
WITH THE NORTHERN TIP OF MADAGASCAR. CHIDO HAS ALSO BEEN FIGHTING
OFF VIGOROUS SHEAR ON THE UPSTREAM SIDE FOR SEVERAL DAYS NOW, ALBEIT 
WITH GREAT SUCCESS. THE SYSTEM IS SMALLER THAN AVERAGE AND WELL 
ENSCONCED FROM THE DRIER AIR SURROUNDING IT. ANIMATED WATER VAPOR 
IMAGERY SHOWS IMPINGEMENT TO THE OUTFLOW OVER THE SOUTHEASTERN  
QUADRANT BUT OTHERWISE SOLID RADIAL OUTFLOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: THE DEEP LAYER MEAN ASSOCIATED WITH THE
SUBTROPICAL RIDGE TO THE SOUTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   KNES: T5.0 - 90 KTS
   DEMS: T6.0 - 115 KTS
   FMEE: T5.0 - 90 KTS
   CIMSS SATCON: 75 KTS AT 131519Z
   CIMSS ADT: 79 KTS AT 131800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 18-24 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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 04S IS EXPECTED TO RAMP UP A NOTCH DURING
THE NEXT 24 HOURS AS IT TRACKS INTO A MORE FAVORABLE ENVIRONMENT
WITH 29-30 DEGREE CELSIUS SEA WATERS AND HIGHER OCEAN HEAT CONTENT 
VALUES. THERE IS ALSO POTENTIAL FOR AN ENHANCEMENT TO POLEWARD OUTFLOW 
OVER THE SOUTHWEST QUADRANT AS THE SYSTEM APPROACHES A DEEP SHORTWAVE
TROF COMING OFF OF AFRICA, WITH A CERTAINTY THAT VERTICAL WIND SHEAR 
WILL EASE SLIGHTLY AS THE SYSTEM GAINS SEPARATION FROM THE SUBTROPICAL 
RIDGE. THE RELATIVELY SMALL SIZE OF CHIDO WILL ALSO WORK IN ITS FAVOR.  
MID-LEVEL MOISTURE PROGS ARE EMPHATIC THAT TC 04S WILL REMAINED 
COCOONED IN DEEP MOISTURE ALL THE WAY ACROSS THE CHANNEL. DESPITE ITS 
SMALL SIZE, THE INTENSITY AND TRACK OF THE SYSTEM FOREBODES DAMAGING 
EFFECTS ON MOST OF THE COMOROS ISLANDS.  GALE FORCE WINDS WILL BEGIN 
ARRIVING ALONG THE COAST JUST AFTER TAU 48.  

MODEL DISCUSSION: TRACK GUIDANCE IS TIGHT AND HAS BEEN CONSISTENT,
GIVING CONFIDENCE TO A LANDFALL NEAR PEMBA WITH EFFECTS EXTENDING
FROM NACALA IN THE SOUTH THROUGH MOCIMBOA DA PRAIA IN THE NORTH. 
INTENSITY GUIDANCE HAS NOT BEEN AS GOOD, WITH CHIDO ADDING ITSELF
TO THE DEVELOPING LIST OF WESTERN INDIAN OCEAN STORMS EXCEEDING
EXPECTATIONS. COUPLED MESOSCALE MODELS HAVE DONE A SIGNIFICANTLY
BETTER JOB CAPTURING THE INTENSITY SURGES THROUGHOUT THE STORMS
LIFESPAN AND ARE WEIGHING HEAVILY IN THE JTWC FORECAST, WHICH RIDES
ABOVE CONSENSUS THROUGH LANDFALL. 

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