WDXS31 PGTW 141500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 11S (FREDDY) WARNING 
NR 024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.4S 90.0E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 1143 NM EAST-SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 32 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
SYMMETRICAL SYSTEM CONTAINING A CLOUD COVERED EYE FEATURE, ALONG
WITH BANDS OF DEEP CONVECTION WRAPPING INTO A LOW-LEVEL CIRCULATION
CENTER (LLCC). A PARTIAL 140807Z AMSR2 IMAGE AND A PARTIAL 140942Z
SSMIS IMAGE BOTH SHOW A WELL-DEFINED MICROWAVE EYE WITH WELL-FORMED
FEEDER BANDS WRAPPING INTO THE LLCC. TC 11S IS IN A MARGINALLY
FAVORABLE ENVIRONMENT FOR FURTHER TROPICAL DEVELOPMENT WITH GOOD
(35-40 KTS) WESTWARD OUTFLOW ALOFT, MARGINAL (15-20 KTS) VERTICAL
WIND SHEAR (VWS), AND WARM (27-28 C) SEA SURFACE TEMPERATURES
(SST). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
THE AFOREMENTIONED MSI. THE INITIAL INTENSITY OF 95 KTS IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON A BLEND OF THE PGTW DVORAK ESTIMATE
AND MULTIPLE AUTOMATED DVORAK ESTIMATES.

INITIAL WIND RADII BASIS: 140344Z SCATTEROMETER DATA

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   KNES: T5.5 - 102 KTS
   DEMS: T5.0 - 90 KTS
   CIMSS SATCON: 98 KTS AT 140800Z
   CIMSS ADT: 90 KTS AT 141315Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE WESTWARD

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 FREDDY CONTINUES ITS WESTWARD TRACK AS IT
RIDES THE NORTHERN PERIPHERY OF THE STR. THE SYSTEM IS EXPECTED TO
REMAIN ON THIS TRACK THROUGH TAU 48. AFTERWARDS, TC 11S WILL MAKE A
SLIGHT DIP POLEWARD AND TRACK WEST-SOUTHWESTWARD AS THE STR WILL
HAVE A LITTLE LESS INFLUENCE AT THIS TIME. AFTER TWO PREVIOUS
STRENGTHENING EVENTS, TC 11S WAS ON A SLIGHT DECREASE IN INTENSITY
DURING THE PREVIOUS FORECAST PERIOD. HOWEVER, IT APPEARS THE UPWARD
TREND IS NOW TAKING PLACE A LITTLE SOONER THAN PREVIOUSLY
ANTICIPATED. AS TC 11S CONTINUES TO TRACK WESTWARD IT WILL
ENCOUNTER A MORE FAVORABLE ENVIRONMENT WITH LOWER VWS, REACHING
ANOTHER PEAK INTENSITY OF 110 KTS BY TAU 72.

MODEL DISCUSSION: THE JTWC MODEL TRACK CONSENSUS REMAINS IN TIGHT
AGREEMENT WITH A GRADUAL SPREAD TO 90 NM AT TAU 48. AFTERWARDS, THE
SPREAD INCREASES TO 185 NM BY TAU 120. ALL MEMBERS AGREE ON THE
WEST-SOUTHWESTWARD SHIFT IN TRACK AFTER TAU 48. BECAUSE OF THIS,
THE JTWC FORECAST TRACK IS PLACED WITH HIGH CONFIDENCE UP TO TAU
72, THEN MEDIUM CONFIDENCE OUT TO TAU 120. THE INTENSITY GUIDANCE
IS ALSO IN TIGHT AGREEMENT WITH THE EXCEPTION OF COAMPS WHICH
INCREASES THE INTENSITY WELL BEYOND THE OTHER CONSENSUS MEMBERS.
THE JTWC INTENSITY FORECAST IS SET WITH MEDIUM CONFIDENCE SLIGHTLY
ABOVE CONSENSUS DUE TO THE INCREASE OF INTENSITY OBSERVED OVER THE
PAST 12 HOURS. 

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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