WDXS31 PGTW 062100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FREDDY) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.0S 118.5E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 364 NM NORTHWEST OF BROOME, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 19 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A COMPACT
SYSTEM WITH A DEEP, SYMMETRICAL CENTRAL DENSE OVERCAST AND FEEDER
BANDS TRAILING FROM THE SOUTH. THE INITIAL POSITION AND INTENSITY
ARE EXTRAPOLATED WITH HIGH CONFIDENCE FROM A 061357Z ASCAT BULLSEYE
PASS AND SUPPORTED BY AGENCY AND AUTOMATED DVORAK FIX CLUSTER. THE
ENVIRONMENT REMAINS HIGHLY FAVORABLE FOR RAPID INTENSIFICATION (RI)
WITH WARM (29-30C) SSTS, LOW (10-15) VERTICAL WIND SHEAR (VWS) AND
MODERATE RADIAL OUTFLOW ALOFT.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

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


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   APRF: T3.0 - 45 KTS
   CIMSS SATCON: 50 KTS AT 061453Z
   CIMSS ADT: 53 KTS AT 061730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL

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 FREDDY WILL CONTINUE ON ITS CURRENT 
SOUTHWESTWARD TRACK OVER THE NEXT 24 HOURS; AFTERWARD, IT WILL LEVEL 
OFF ON A MORE WEST-SOUTHWESTWARD DIRECTION AS THE STEERING STR BUILDS. 
THE HIGHLY FAVORABLE ENVIRONMENT WILL FUEL RI TO A PEAK OF 105KTS BY 
TAU 48. AFTERWARD, INCREASING VWS AND THE INTRUSION OF
MID-LEVEL DRY AIR WILL RAPIDLY, ALBEIT MOMENTARILY, ERODE THE
SYSTEM DOWN TO 85 KTS BY TAU 72. AFTER TAU 72, IMPROVED POLEWARD
OUTFLOW WILL OFFSET THE INCREASED VWS AND PROMOTE A SECONDARY
INTENSIFICATION TO 95KTS BY TAU 96 BEFORE VWS FURTHER INCREASES AND
WEAKENS THE CYCLONE DOWN TO 85KTS BY TAU 120.  

MODEL DISCUSSION: NUMERICAL TRACK MODELS ARE IN FAIRLY TIGHT
AGREEMENT WITH A GRADUAL SPREADING TO 200NM BY TAU 120 WITH NAVGEM
THE NOTABLE LEFT-OF-TRACK OUTLIER. UP TO TAU 72, THERE IS HIGH
CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID JUST TO THE
RIGHT OF CONSENSUS TO OFFSET NAVGEM. AFTER TAU 72, THE TRACK
CONFIDENCE IS MEDIUM AS THE SPREAD WIDENS. THE INTENSITY FORECAST
IS MEDIUM UP TO TAU 72 THEN LOW AFTERWARD DUE TO THE COMPLEX
FORECAST INTENSITY DYNAMICS.

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