WDPN32 PGTW 211500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 11W (ELEVEN) 
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.0N 142.8E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 204 NM WEST-NORTHWEST OF SAIPAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A RAPIDLY
CONSOLIDATING SYSTEM WITH FLARING DEEP CONVECTION IN THE CENTRAL
DENSE OVERCAST AND FRAGMENTED, FORMATIVE BANDS WRAPPING FROM THE
SOUTHERN PERIPHERY INTO A MOSTLY OBSCURED LOW LEVEL CIRCULATION
CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE 
USING LOW CLOUD TRACING INTO THE OBSCURED LLCC AND LINED UP WITH A 
MICROWAVE LLCC FEATURE IN THE 210803Z SSMIS IMAGE SUITE. THE INITIAL 
INTENSITY OF 25KTS IS ALSO ASSESSED WITH MEDIUM CONFIDENCE BASED ON 
THE DVORAK ESTIMATE OF T1.5 FROM ALL THREE REPORTING AGENCIES - PGTW, 
KNES, AND RJTD. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH WARM 
SST AND MODERATE RADIAL OUTFLOW OFFSET BY MODERATE VERTICAL WIND 
SHEAR.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T1.5 - 25 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TD 11W WILL TRACK MORE NORTH-NORTHWESTWARD
ALONG THE WESTERN PERIPHERY OF THE STEERING STR TOWARD JAPAN. THE
FAVORABLE ENVIRONMENT WILL PROMOTE GRADUAL INTENSIFICATION TO 60KTS
BY TAU 96. AFTERWARD, INCREASING POLEWARD OUTFLOW AS THE SYSTEM 
APPROACHES THE PREVAILING WESTERLIES, WILL FUEL RAPID INTENSIFICATION 
TO 85KTS BY TAU 120.  

MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIRLY GOOD AGREEMENT
WITH A GRADUAL SPREAD TO 239NM BY TAU 120 WITH UEMN ON THE LEFT AND
NVGM ON THE RIGHT MARGIN OF THE ENVELOPE. HOWEVER, GIVEN THE
FORMATIVE NATURE OF THE SYSTEM THERE IS ONLY MEDIUM CONFIDENCE TO
THE JTWC TRACK FORECAST. THERE IS MEDIUM CONFIDENCE IN THE
INTENSITY FORECAST TO TAU 72, THEN LOW CONFIDENCE AFTERWARD GIVEN
THE ANTICIPATED VARIABILITY OF RAPID INTENSIFICATION.  

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