WDXS31 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FREDDY)     
WARNING NR 022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.4S 94.6E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 238 NM SOUTH-SOUTHWEST OF THE COCOS
ISLANDS
   MOVEMENT PAST 6 HOURS: WESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 40 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
DESPITE PERSISTENT EASTERLY VERTICAL WIND SHEAR (20 TO 25 KNOTS),
TROPICAL CYCLONE (TC) 11S HAS REMAINED RESILIENT AND HAS MAINTAINED
A SYMMETRIC CONVECTIVE CORE. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS A TIGHT TEMPERATURE GRADIENT OVER THE
EASTERN PERIPHERY, EVIDENCE OF THE EASTERLY VWS, WITH DEEP
CONVECTION SHEARING TO THE WEST. A 130955Z SSMIS 91GHZ MICROWAVE
IMAGE REVEALS A COMPACT 100-120NM DIAMETER CENTRAL DENSE OVERCAST
WITH A MICROWAVE EYE FEATURE OVER THE SOUTHEASTERN EDGE OF THE
CONVECTIVE CORE, LENDING HIGH CONFIDENCE IN THE INITIAL POSITION.
THE INITIAL INTENSITY OF 90 KTS IS ASSESSED WITH HIGH CONFIDENCE
BASED ON THE KNES AND APRF DVORAK ESTIMATES.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA AND PERSISTENCE 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   KNES: T5.0 - 90 KTS
   APRF: T5.0 - 90 KTS
   CIMSS SATCON: 97 KTS AT 130639Z
   CIMSS ADT: 85 KTS AT 131300Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: MODERATE WESTWARD

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 11S IS FORECAST TO TRACK WESTWARD THROUGH
THE FORECAST PERIOD ALONG THE NORTHERN PERIPHERY OF THE STR. TC 11S
HAS CONTINUED TO PROVE RESILIENT, COCOONING ITSELF FROM SHORT
PERIODS OF STRONGER VWS AND DRY AIR ENTRAINMENT WHILE MAINTAINING A
COMPACT CONVECTIVE CORE. ONCE AGAIN, THE SYSTEM IS BATTLING
EASTERLY VWS AND IS EXPECTED TO WEAKEN OVER THE NEXT 24 HOURS.
AFTER TAU 24, VWS WILL RELAX ALLOWING THE SYSTEM TO REINTENSIFY
QUICKLY TO A PEAK OF 110 KNOTS BY TAU 72. AFTER TAU 72, SST IS
EXPECTED TO DECREASE SLIGHTLY TO 27C, AND VWS WILL GRADUALLY CLIMB 
WITH DRY AIR ENTRAINMENT, WHICH SHOULD WEAKEN THE SYSTEM.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH THE FORECAST PERIOD WITH A 115NM CROSS-TRACK SPREAD IN
SOLUTIONS AT TAU 72 INCREASING TO 205NM BY TAU 120. RELIABLE
INTENSITY GUIDANCE INDICATES GOOD AGREEMENT THROUGH TAU 24
SUPPORTING THE WEAKENING TREND. AFTER TAU 24, THERE IS A LARGE
SPREAD IN INTENSITY GUIDANCE THROUGH TAU 120. OVERALL, THERE IS
MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST. THE 130600Z
COAMPS-TC ENSEMBLE INDICATES AN INCREASING PROBABILITY (40 TO 50
PERCENT) OF RAPID INTENSIFICATION OCCURRING FROM TAU 36 TO TAU 78,
WHICH ALIGNS WELL WITH THE JTWC INTENSITY FORECAST. 

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