WDXS31 PGTW 081500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FREDDY) WARNING 
NR 053//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.0S 40.2E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 72 NM NORTH OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
PRIMARY CELL OF DEEP CONVECTION ORBITING THE LLCC AS 11S STRUGGLES
TO REFORM ITS CORE STRUCTURE. A COMPARISON BETWEEN THE 081044Z
AMSR2 89GHZ AND 37GHZ COLOR COMPOSITE MICROWAVE IMAGES REVEALS THAT
THE LOW LEVEL CIRCULATION CENTER (LLCC) AND UPPER LEVEL CIRCULATION
CENTER (ULCC) ARE SLIGHTLY OFFSET. FURTHERMORE, THESE IMAGES REVEAL
LARGE PORTIONS OF THE SYSTEM HAVE BEEN ERODED BY DRY AIR, WHICH HAS
EXPOSED MUCH OF THE EASTERN SEMICIRCLE. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON EIR AND AMSR2 IMAGERY. THE
INITIAL INTENSITY OF 95 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON AGENCY DVORAK INTENSITY ESTIMATES INDICATING T5.0-T5.5
WHILE NEARLY ALL AUTOMATED INTENSITY ESTIMATES HAVE PREMATURELY
FALLEN BELOW 80KTS, FOLLOWING THE LOSS OF THE EYE FEATURE.

INITIAL WIND RADII BASIS: 080706Z ASCAT-C SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE WEST AND SOUTHWEST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   KNES: T5.5 - 102 KTS
   DEMS: T5.0 - 90 KTS
   FMEE: T5.0 - 90 KTS
   CIMSS SATCON: 76 KTS AT 081109Z
   CIMSS ADT: 74 KTS AT 080900Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: WEAK RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   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 (FREDDY) IS FORECAST TO CONTINUE
TRACKING NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE
SUBTROPICAL RIDGE BUILDING TO THE SYSTEMS SOUTH AND WEST. OVER THE
PAST 12 HOURS AS 11S HAS PROGRESSED NORTHWESTWARD, THE SYSTEM HAS
BEEN CUT OFF FROM THE SUB-TROPICAL JET TO THE SOUTH WHICH WAS
PROVIDING VIGOROUS UPPER LEVEL OUTFLOW. AS THIS OUTFLOW WAS
RESTRICTED, THE SYSTEM LOST ITS EYE AND STRUGGLED TO MAINTAIN
CONVECTIVE COHESION. COMING AS BOTH A BLESSING AND CURSE, AS THE
STR TO THE WEST BUILDS, IT WILL PROVIDE IMPROVED UPPER LEVEL
OUTFLOW WHILE ALSO BRINGING COPIOUS AMOUNTS OF DRY AIR INTO THE
SYSTEM FROM THE WEST. THESE FACTORS COUPLED WITH SLIGHTLY COOLING
SSTS WILL GRADUALLY WEAKEN 11S UNTIL ONCE AGAIN MAKING LANDFALL ON
THE COAST OF MOZAMBIQUE. WITH A FORECAST INTENSITY OF 75KTS BY TAU
48, 11S WILL PROCEED INLAND THROUGH 72 AND QUICKLY WEAKEN UNTIL
DISSIPATION NEAR TAU 96.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH ALL
MEMBERS CLOSELY FOLLOWING THE JTWC FORECAST TRACK THROUGH TAU 72
WITH MINIMAL SPREADING IN THE EXTENDED TRACK FORECAST. FOR THESE
REASONS THE JTWC TRACK FORECAST IS PLACED INITIALLY WITH HIGH
CONFIDENCE AND WITH MEDIUM CONFIDENCE IN THE EXTENDED TRACK. WITH
THE EXCEPTION OF HWRF, RELIABLE MODEL INTENSITY GUIDANCE IS IN
AGREEMENT THAT THE SYSTEM WILL WEAKEN THROUGH THE FORECAST PERIOD.
GFS AND COAMPS-TC INDICATE A VERY AGGRESSIVE AND UNFOUNDED
WEAKENING TREND WHILE DECAY-SHIPS TAKES A MORE GRADUAL AND
REALISTIC WEAKENING TREND. THE JTWC INTENSITY FORECAST IS THEREFORE
PLACED ABOVE THE MULTI-MODEL CONSENSUS AND INITIALLY NEAR
DECAY-SHIPS WITH OVERALL MEDIUM CONFIDENCE.

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