WDPN31 PGTW 221500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (SIX) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.3N 141.5E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 201 NM WEST OF ANDERSEN AFB, GUAM
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 13 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS THE
SYSTEM HAS MAINTAINED OVERALL CONVECTIVE SIGNATURE WITH A CENTRAL
DENSE OVERCAST TOTALLY OBSCURING THE LOW LEVEL CIRCULATION CENTER.
FEEDER BANDS REMAIN MINIMAL, DISORGANIZED, AND FRAGMENTED. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 221101Z
ASCAT BULLSEYE PASS. THE INITIAL INTENSITY OF 35 KTS IS PLACED WITH
HIGH CONFIDENCE BASED ON OVERALL ASSESSMENT OF AGENCY AND OBJECTIVE
DVORAK ESTIMATES AND IS SUPPORTED BY THE 221101Z ASCAT PASS SHOWING
30-40KT WIND BARBS ALONG THE NORTHEAST QUADRANT. THE ENVIRONMENT IS
MARGINALLY FAVORABLE WITH WARM SSTS AND LOW VWS TEMPERED BY A WEAK
POLEWARD OUTFLOW INTO A TUTT CELL TO THE NORTHEAST.

INITIAL WIND RADII BASIS: EXTRAPOLATED FROM THE 221101Z ASCAT PASS.

CURRENT STEERING MECHANISM: THE CYCLONE IS TRACKING ALONG THE
SOUTHWEST PERIPHERY OF THE LOW- TO MID-LEVEL REFLECTION OF THE STR
TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   CIMSS SATCON: 46 KTS AT 220852Z
   CIMSS ADT: 43 KTS AT 220840Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 0-5 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: WEAK POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 06W WILL CONTINUE ON ITS CURRENT TRACK THEN
TURN MORE NORTHWARD AFTER TAU 48 AND CREST THE STR AXIS BY TAU 72.
AFTERWARD, IT WILL ACCELERATE NORTH-NORTHEASTWARD, THEN AFTER TAU
96, NORTHEASTWARD ON THE POLEWARD SIDE OF THE STR. THE MARGINALLY
FAVORABLE ENVIRONMENT WILL FUEL A STEADY INTENSIFICATION TO A PEAK
OF 65KTS BY TAU 72 AS POLEWARD OUTFLOW INCREASES FOLLOWING INITIAL
EXPOSURE TO THE PREVAILING WESTERLIES. AFTERWARD, INCREASING VWS
AND COOLING SSTS WILL SLOWLY ERODE THE CYCLONE. CONCURRENTLY BY TAU
96, IT WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) AS IT ENTERS THE
COLD BAROCLINIC ZONE AND MERGES WITH THE BAIYU FRONTAL BOUNDARY
SOUTHEAST OF JAPAN. BY TAU 120, TS 06W WILL COMPLETE ETT AND EMBED
INTO THE GRADIENT FLOW AS A STORM-FORCE COLD CORE LOW WITH AN
EXPANDING WIND FIELD.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH A
GRADUAL AND EVEN SPREAD TO 176NM AT TAU 72, THEN TO 150NM AT TAU 120.
THERE IS, HOWEVER, NOTABLE DIFFERENCES IN ALONG-TRACK SPEEDS AFTER 
TAU 72. IN VIEW OF THESE, THERE IS HIGH CONFIDENCE IN THE NEAR- TO 
MID-TERM PORTION OF THE JTWC FORECAST TRACK THAT IS LAID CLOSE TO THE
MULTI-MODEL CONSENSUS. THERE IS ONLY MEDIUM CONFIDENCE IN THE
EXTENDED POTION OF THE FORECAST TO ACCOUNT FOR THE DIFFERENCES IN
ALONG-TRACK ACCELERATION. 

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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