WDPN31 PGTW 240900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 08W (EIGHT) WARNING 
NR 006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.4N 149.1E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 196 NM EAST OF ANATAHAN
   MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
AS THE TERMINATOR LINE WASHES OVER 08W, THE LAST FEW FRAMES OF
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY
EXPOSED LOW LEVEL CIRCULATION CENTER WITH ALL DEEP CONVECTIVE
STRUCTURES LIMITED TO THE EASTERN SEMICIRCLE. WITH A COMPLETE LACK
OF NEW MICROWAVE OR SCATTEROMETRY IMAGERY, WE ARE FORCED TO RELY ON
EXTRAPOLATION OF PREVIOUS 240012Z ASCAT-C SCATTEROMETRY IMAGERY.
WITH LITTLE TO NO CHANGE IN THE STRUCTURE OF THE SYSTEM ON MSI, THE
SCATTEROMETRY IMAGERY CONFIRMS THE DIAGNOSIS OF 08W AS A MONSOON
DEPRESSION, WITH A RADIUS OF MAXIMUM WINDS (RMW) EXCEEDING 150NM
AND A RADIUS OF THE OUTERMOST ISOBAR (ROMCI) IN EXCESS OF 400NM.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON MSI
IMAGERY. THE INITIAL INTENSITY OF 25 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON NO APPRECIABLE CHANGE IN ANY AGENCY DVORAK OR
AUTOMATED INTENSITY ESTIMATE SINCE THE PREVIOUS FORECAST.

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

CURRENT STEERING MECHANISM: BUILDING INFLUENCE OF A SUBTROPICAL
RIDGE (STR) TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.5 - 35 KTS
   CIMSS ADT: 39 KTS AT 240530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TD 08W IS FORECAST TO EXECUTE AN ABOUT-FACE
WITHIN THE COMING HOURS, AS THE BUILDING STR TO THE EAST BEGIN TO
INFLUENCE THE SYSTEM. BY TAU 12, THE SYSTEM WILL BE TRACKING
GENERALLY NORTH-NORTHEASTWARD AND GRADUALLY INTENSIFYING AS THE
UPPER LEVEL OUTFLOW BEGINS TO IMPROVE. NEAR TAU 48, THE SYSTEM WILL
BEGIN TO TURN NORTH-NORTHWESTWARD AS A STR BUILDS TO THE NORTH. AS
THE SYSTEM RIDES THIS RIDGE POLEWARD, THE VERY LARGE MONSOON
DEPRESSION SIZED CIRCULATION WILL STRUGGLE TO GAIN ANY NOTABLE
INTENSITY. BY TAU 120, AS THE SYSTEM PASSES WELL EAST OF TOKYO
JAPAN, THE SYSTEM WILL BE APPROXIMATELY 40KTS AS IT NEARS THE AXIS
OF THE STR. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH ALL
MEMBERS GENERALLY FOLLOWING THE MULTI-MODEL CONSENSUS, RESULTING IN
THE JTWC FORECAST TRACKING BEING PLACED WITH OVERALL MEDIUM
CONFIDENCE. RELIABLE MODEL INTENSITY GUIDANCE IS IN POOR AGREEMENT
WITH MOST MEMBERS UNREALISTICALLY ROCKETING THE SYSTEM UP TO NEAR
TYPHOON INTENSITY BY TAU 60, DESPITE ITS MASSIVE SIZE. THE JTWC
FORECAST IS THEREFOR PLACED BELOW THAT BASED ON ANALYSIS OF THE
ENVIRONMENTAL CONDITIONS THROUGH THE FORECAST PERIOD, THOUGH
CONFIDENCE IS VERY LOW DUE TO THE LARGE DEVIATION FROM THE MODEL
GUIDANCE.

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