WDXS32 PGTW 201500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 16S (ELEANOR)   
WARNING NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.8S 59.6E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 471 NM NORTH-NORTHEAST OF ST DENIS, LA
                         REUNION
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED PROXYVIS SATELLITE IMAGERY DEPICTS A PARTIALLY EXPOSED,
WELL-DEFINED LOW-LEVEL CIRCULATION CENTER WITH IMPROVED CONVECTIVE
BANDING OVER THE SOUTHERN SEMICIRCLE WRAPPING INTO THE WESTERN
QUADRANT. HOWEVER, DRY-AIR ENTRAINMENT IS EVIDENT OVER THE NORTHEAST 
QUADRANT AND IS CONTINUING TO HINDER OVERALL CONVECTIVE DEVELOPMENT. 
THE DRY-AIR ENTRAINMENT IS ALSO OBSERVABLE IN THE 201227Z 91 GHZ 
SSMIS MICROWAVE IMAGE WHICH REVEALS AN ASYMMETRIC CONVECTIVE 
STRUCTURE WITH A DRY SLOT EXTENDING INTO THE NORTHEAST QUADRANT. 
ROBUST UPPER-LEVEL RADIAL OUTFLOW PERSISTS WITH ENHANCED POLEWARD 
OUTFLOW INTO THE STRONG MID-LATITUDE WESTERLIES TO THE SOUTH. THERE 
IS HIGH CONFIDENCE IN THE INTIAL POSITION BASED ON A DEVELOPING 
MICROWAVE EYE FEATURE IN THE 201227Z SSMIS 37 GHZ IMAGE. THE INITIAL 
INTENSITY OF 45 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON 
RECENT ASCAT DATA AS WELL AS SUBJECTIVE DVORAK ESTIMATES RANGING FROM 
45 TO 55 KNOTS. CIMSS OBJECTIVE INTENSITY ESTIMATES GENERALLY RANGE 
FROM 45 TO 57 KTS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: NEAR EQUATORIAL RIDGE (NER) POSITIONED
TO THE NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T3.5 - 55 KTS
   FMEE: T3.0 - 45 KTS
   FIMP: T3.0 - 45 KTS
   CIMSS ADT: 57 KTS AT 201200Z
   CIMSS AIDT: 50 KTS AT 201200Z
   CIMSS DPRINT: 45 KTS AT 201300Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL
   OTHER FACTORS: DRY-AIR ENTRAINMENT AROUND THE NORTHERN
                  SEMICIRCLE. 

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: TROPICAL CYCLONE (TC) 16S IS FORECAST TO 
PROGRESS SOUTH-SOUTHEASTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE 
NER THROUGH TAU 12. AFTER TAU 12, THE SYSTEM WILL TRACK SOUTH-
SOUTHWESTWARD THROUGH TAU 96 AS THE SUBTROPICAL RIDGE (STR) BUILDS TO 
THE EAST. AFTER TAU 96, TC 16S WILL BEGIN SLOWING DOWN DURING ITS 
EXPECTED SHARP TURN TO THE WEST-NORTHWEST AS A STR BUILDS TO THE 
SOUTH, FORCING THE CYCLONE WESTWARD JUST SOUTH OF LA REUNION NEAR TAU 
120. TC 16S IS FORECAST TO INTENSIFY STEADILY THROUGH TAU 48 AS THE 
CORE MOISTENS AND DRY AIR ENTRAINMENT DECREASES, WITH A PEAK OF 75 
KNOTS AT TAU 48 FUELED BY FAVORABLE UPPER-LEVEL CONDITIONS AND WARM 
SEA SURFACE TEMPERATURES (28C-30C). AFTER TAU 48, THE ENVIRONMENTAL 
CONDITIONS WILL GRADUALLY WORSEN WITH INCREASING VWS (25-30 KNOTS) 
AND DRY AIR ENTRAINMENT LEADING TO A STEADY WEAKENING TREND. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT WITH 
TWO DISTINCT CLUSTERS OF AIDS. THE CLUSTER COMPOSED OF AFUM, UEMN AND 
EGRR ARE POSITIONED ALONG THE EASTERN EDGE OF THE AIDS ENVELOPE. THE 
REMAINDER OF THE GUIDANCE INCLUDING ECMWF, EEMN AND GFS TAKE A MORE 
SOUTH-SOUTHWESTWARD TRACK WITH A SHARP WESTWARD TURN AFTER TAU 72. 
THE JTWC FORECAST TRACK IS POSITIONED WEST OF THE CONSENSUS ALIGNED 
MORE CLOSELY WITH THE BETTER GUIDANCE. THE JTWC INTENSITY FORECAST IS 
HEDGED SLIGHTLY HIGHER THAN THE JTWC INTENSITY CONSENSUS (ICNW) AND 
REMAINS CONSISTENT WITH THE PREVIOUS FORECAST.

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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