WDXS31 PGTW 091500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FREDDY) WARNING 
NR 055//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.5S 38.8E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 180 NM NORTH-NORTHWEST OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 29 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A STRUGGLING
MASS OF CONVECTION BLOOMING OVER AN ASSESSED LOW LEVEL CIRCULATION
CENTER (LLCC). A PARTIAL 091007Z GMI 89 GHZ IMAGE SHOWS A DEEP BAND
OF CONVECTION IN THE SOUTHERN PERIPHERY WRAPPING AROUND THE
EVALUATED LLCC. ALTHOUGH THE MSI ANALYSIS REVEALS IMPROVING
CONVECTION OVER THE LLCC, MICROWAVE IMAGERY OVER THE PAST 12 HOURS
SUGGESTS A DISPROPORTIONATE SYSTEM THAT IS STILL TRYING TO COME
TOGETHER. ENVIRONMENTAL ANALYSIS REVEALS TC 11S CONTINUES TO BATTLE
WITH A GOOD AMOUNT OF DRY AIR ENTRAINMENT IN THE WESTERN PERIPHERY.
TC FREDDY IS IN A MARGINALLY FAVORABLE ENVIRONMENT FOR FURTHER
TROPICAL DEVELOPMENT. THESE CONDITIONS ARE CHARACTERIZED BY LOW
(05-10 KTS) VERTICAL WIND SHEAR (VWS), A HEALTHY 850 MB VORTICITY
SIGNATURE, AND VERY WARM (27-28 C) SEA SURFACE TEMPERATURES (SST),
OFFSET BY THE LACK OF UPPER-LEVEL OUTFLOW TO GIVE TC 11S THE
EXHAUST IT NEEDS TO CONTINUE TO DEEPEN. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON THE AFOREMENTIONED MSI,
MICROWAVE IMAGERY, AND MULTI-AGENCY FIXES. THE INITIAL INTENSITY OF
60 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED OFF A BLEND OF
MULTI-AGENCY AND AUTOMATED DVORAK ESTIMATES.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
SOUTHWEST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T4.0 - 65 KTS
   FMEE: T4.0 - 77 KTS
   CIMSS SATCON: 58 KTS AT 091051Z
   CIMSS ADT: 53 KTS AT 091230Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: WEAK WESTWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC FREDDY CONTINUES ITS NORTHWESTWARD TRACK
AND WILL INTENSIFY ONCE AGAIN BEFORE MAKING LANDFALL AT
APPROXIMATELY TAU 30. BETWEEN TAUS 12 AND 24, TC 11S WILL BEGIN TO
SLOWLY INCREASE IN INTENSITY TO 70 KTS DUE TO AN IMPROVING
STRUCTURE AND REGAINING MORE MID-LEVEL MOISTURE. IN ADDITION, TC
FREDDY WILL ENTER AN INCREASINGLY FAVORABLE ENVIRONMENT DEFINED BY
LOWER VWS AND HIGHER OCEAN HEAT CONTENT (OHC). BY TAU 36, TC 11S
WILL REACH ITS MAX INTENSITY OF 75 KNOTS AS THE SYSTEM MAKES
LANDFALL JUST SOUTH OF QUELIMANE, MOZAMBIQUE. AFTERWARDS, TC 11S
WILL DECREASE IN INTENSITY DUE TO LAND INTERACTION AFTER TAU 36
INTO TAU 48. BY TAU 72, TC 11S WILL DISSIPATE NEAR THE MOZAMBIQUE
AND SOUTHERN MALAWI BORDER.

MODEL DISCUSSION: THE JTWC TRACK CONSENSUS MEMBERS ARE IN AGREEMENT
AS FAR AS TRACK DIRECTION, HOWEVER, THEY DISAGREE WITH TRACK SPEED.
THE GFS DETERMINISTIC AND ENSEMBLE SOLUTIONS DISPLAY THE SLOWEST
TRACK SPEEDS WITH INDICATIONS THAT TC 11S WILL TURN ALMOST 180
DEGREES AND HEAD BACK OVER THE MOZAMBIQUE CHANNEL BETWEEN TAUS 96
AND 120. AFUM AND THE UK MODELS SHOW FASTER TRACK SPEEDS TAKING THE
REMNANTS OF THE SYSTEM INTO ZAMBIA. DUE TO THIS DISPARITY IN THE
MODELS, THE JTWC FORECAST TRACK IS SET WITH LOW CONFIDENCE. THE
JTWC INTENSITY CONSENSUS MEMBERS ALL AGREE ON AN INTENSIFYING
SCENARIO UP TO AND INCLUDING LANDFALL, THEN A DECREASE AFTERWARDS.
THE JTWC INTENSITY FORECAST IS SET WITH MEDIUM CONFIDENCE.

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