WDXS31 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FREDDY) WARNING 
NR 017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.8S 104.8E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 262 NM SOUTH OF CHRISTMAS ISLAND,
AUSTRALIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 38 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A COMPACT
SYSTEM THAT HAS MAINTAINED OVERALL SYMMETRICAL CONVECTIVE SIGNATURE
WITH SHORT SHALLOW FEEDER BANDS WRAPPED CLOSE TO THE CORE. THE 
CENTRAL DENSE OVERCAST HAS SLIGHTLY DEEPENED OVER THE LAST 12 HRS. 
THE INITIAL POSITION IS EXTRAPOLATED WITH HIGH CONFIDENCE FROM A 
MICROWAVE EYE FEATURE IN THE 102206Z SSMIS 89GHZ IMAGES. THE INITIAL 
INTENSITY IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON AN OVERALL 
ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE 
SLIGHT 12-HR IMPROVEMENT. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT 
WITH WARM SST, LOW VWS, AND WITH MODERATE RADIAL OUTFLOW.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   DEMS: T4.5 - 77 KTS
   APRF: T4.5 - 77 KTS
   CIMSS SATCON: 64 KTS AT 101843Z
   CIMSS ADT: 84 KTS AT 102330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   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 FREDDY WILL CONTINUE ON A GENERALLY WESTWARD 
TO WEST-SOUTHWESTWARD TRACK UNDER THE STEERING STR. THE FAVORABLE 
ENVIRONMENT WILL FUEL A STEADY INTENSIFICATION TO 100KTS BY 36. 
AFTERWARD, INCREASING VWS WILL OFFSET THE FAVORABLE SST AND OUTFLOW 
AND TEMPORARILY WEAKEN THE SYSTEM DOWN TO 75KTS BY TAU 72. AFTER TAU 
72, VWS WILL ONCE AGAIN RELAX PROMOTING ANOTHER INTENSIFICATION PHASE 
AND BY TAU 120, THE INTENSITY WILL REACH 100KTS. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY GOOD AGREEMENT WITH
AN EVEN AND GRADUAL SPREAD TO 234NM BY TAU 120, LENDING HIGH
CONFIDENCE TO THE JTWC TRACK FORECAST. THE INTENSITY FORECAST IS AT
MEDIUM CONFIDENCE FOR THE DURATION OF THE FORECAST DUE TO THE
UP-AND-DOWN INTENSITY CHANGES. 

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