WDPN31 PGTW 120300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (MARIA) WARNING NR 
021//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 39.0N 141.7E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 87 NM SOUTH-SOUTHEAST OF MISAWA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 12 KTS

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS LINES OF
CONVECTIVE BANDING WRAPPING INTO A LOW-LEVEL CIRCULATION CENTER
(LLCC) OBSCURED BY CENTRALIZED DEEP CONVECTION. CONVECTION IN THE
WESTERN PERIPHERY OF THE SYSTEM HAS BEGUN TO COLLAPSE DUE TO
SHIELDING FROM THE JAPANESE ALPS. A 122037Z RCM-2 SYNTHETIC
APERTURE RADAR (SAR) IMAGE DEPICTS AN ASYMMETRIC SYSTEM WITH THE
BULK OF CONVECTION POSITIONED TO THE NORTHEAST. THE WIND SPEED
ANALYSIS REVEALS A MAXIMUM OF 51KTS OF WIND IN THE NORTHEASTERN
PERIPHERY OF THE SYSTEM. THE INTENSITY IS ASSESSED TO HAVE
DECREASED IN THE FOUR HOURS SINCE THE SAR PASS DUE TO COOL SEA SURFACE
TEMPERATURES (SST) BY THE JAPANESE COASTLINE. THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED ANIMATED
MSI AND SAR IMAGERY. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED
WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED SAR IMAGERY AND
THE AGENCY AND OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: ON THE WESTERN PERIPHERY OF A
SUBTROPICAL RIDGE (STR) TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T2.5 - 35 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 5-10 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: MODERATE RADIAL

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: TROPICAL STORM (TS) 06W IS FORECAST TO
CONTINUE TRACKING NORTHWESTWARD ON THE WESTERN PERIPHERY OF THE
SUBTROPICAL RIDGE TO THE EAST. THE TOPOGRAPHIC INTERACTION WITH THE
MOUNTAINOUS TERRAIN OF NORTH JAPAN WILL CAUSE THE VORTEX TO SHALLOW
AND WEAKEN TO 35KTS OVER THE NEXT TWELVE HOURS. AFTER TRACKING BACK
OUT OVER WATER, TS 06W WILL CONTINUE TO WEAKEN AFTER TAU 12
REACHING DISSIPATION BY TAU 36 WHILE IN COOL SEA SURFACE
TEMPERATURES AND UNFAVORABLE UPPER-LEVEL DIFFLUENCE DESPITE
FAVORABLE LOW VERTICAL WIND SHEAR. LASTLY, BETWEEN TAU 24-36 THE
SYSTEM WILL BEGIN TO CURVE NORTH-NORTHEASTWARD WITH THE
CLIMATOLOGICAL FLOW OF THE SOUTHWEST MONSOON.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE TIGHTLY TRACKS TS
06W NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR TO THE
EAST THROUGH THE END OF THE FORECAST PERIOD. THE MARGINAL
CROSS-TRACK SPREAD OF 40NM SUPPORTS THE HIGH CONFIDENCE IN THE JTWC
FORECAST WHICH LIES CLOSELY TO THE MULTI-MODEL CONSENSUS MEAN. THE
JTWC INTENSITY GUIDANCE ALSO STRONGLY SIGNALS CONSISTENT AND RAPID
WEAKENING THROUGHOUT THE REMAINDER OF THE FORECAST GOVERNED
PRIMARILY BY TOPOGRAPHIC INTERACTION AND COLD SSTS OFF OF THE COAST
OF NORTH JAPAN.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
NNNN