WDPN31 PGTW 092100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (MARIA) WARNING NR 
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 34.1N 146.0E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 442 NM SOUTH-SOUTHEAST OF MISAWA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 27 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A FULLY
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH CONVECTION
DISPLACED TO THE NORTHEAST DUE TO SOUTHWESTERLY VERTICAL WIND
SHEAR. ADDITIONALLY, THE EIR DEPICTS CLEAR AIR TO THE SOUTH AND
SOUTHWEST WHERE DRY AIR HAS WRAPPED INWARD TO THE VORTEX. A 091705Z
TROPICS-3 91GHZ IMAGE DEPICTS A LLCC WITH MINIMAL CONVECTIVE
BANDING SURROUNDING THE VORTEX. WATER VAPOR IMAGERY DEPICTS STRONG
POLEWARD AND EQUATORWARD OUTFLOW. THE INITIAL POSITION IS PLACED WITH 
HIGH
CONFIDENCE BASED ON THE AFOREMENTIONED ANIMATED EIR AND
AFOREMENTIONED MICROWAVE IMAGERY. THE INITIAL INTENSITY OF 45 KTS
IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE DEGRADING STRUCTURE
OF TROPICAL STORM (TS) 06W AND THE AGENCY AND OBJECTIVE FIXES
BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T2.5 - 35 KTS
   CIMSS ADT: 43 KTS AT 1900ZZ

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE CURRENT ENVIRONMENT HAS CAUSED
FURTHER WEAKENING THAN EXPECTED, THEREBY LOWERING THE INTENSITIES
THROUGH THE END OF THE FORECAST.

FORECAST DISCUSSION: TS 06W IS FORECAST TO CONTINUE CURVING ALONG A
TRACK TOWARDS THE NORTHWEST FOR THE FIRST 48 HOURS OF THE FORECAST
NORTHWESTWARD UNDER THE INFLUENCE OF A STR TO THE NORTHEAST. BEYOND
TAU 48, THE SYSTEM WILL TRACK DUE NORTHWEST ACROSS THE MAINLAND OF
JAPAN. SINCE TS 06W HAS WEAKENED, IT IS FORECAST TO INTENSIFY
SLIGHTLY TO 50KTS OVER THE NEXT 12 HOURS AS IT ENTERS A REGION OF
HIGHER OCEAN HEAT CONTENT. BEYOND TAU 12, THE UPPER-LEVEL
ENVIRONMENT WILL BECOME UNFAVORABLE AND CONVERGENT ALOFT. FURTHER
IMPACTING INTENSITY, TS 06W WILL ENTER A REGION OF COOLER THAN 26C
SEA SURFACE TEMPERATURES AROUND TAU 48. AS THE SYSTEM CONTINUES TO
INTERACT WITH THE MOUNTAINOUS TERRAIN OF NORTHERN JAPAN, WEAKENING
WILL CONTINUE THROUGH TAU 72 WHEN TS 06W WILL COME BACK OUT OVER
COOLER WATER. THE UPPER-LEVEL ENVIRONMENT WILL BE DIVERGENT AND
REINFORCE WEAKENING THROUGH THE END OF THE FORECAST PERIOD. 

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
THAT THE SYSTEM WILL CURVE NORTHWEST ON THE PERIPHERY OF A STR TO
THE NORTHEAST FOR THE ENTIRETY OF THE FORECAST, REPRESENTED BY A
MAXIMUM CROSS-TRACK SPREAD OF 150NM. THE JTWC INTENSITY GUIDANCE IS
RATHER SPREAD WITH GFS FORECASTING INTENSIFICATION AND A PEAK OF
57KTS, AND COAMPS-TC CONTINUALLY WEAKENING TO DISSIPATION BY TAU
36. THE JTWC FORECAST MOST CLOSELY REPRESENTS THE CONSENSUS MEAN,
TAKING INTO ACCOUNT THE UNFAVORABLE UPPER-LEVEL ENVIRONMENT, OCEAN
HEAT CONTENT, AND SEA SURFACE TEMPERATURES IN THE LATER FORECAST.

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