WDPN31 PGTW 022100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (JANGMI) WARNING NR 
027//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 33.3N 135.0E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 157 NM EAST-SOUTHEAST OF IWAKUNI, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 23 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM (TS) 06W AS A HIGHLY SHEARED, BROAD, AND ELONGATED PARTIALLY
EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) INUNDATED WITH
SIGNIFICANT DRY AIR FORCING INTO THE CORE FROM THE WEST AND SOUTH.
THE ENVIRONMENT IS ASSESSED TO BE HIGHLY UNFAVORABLE, CHARACTERIZED
BY HIGH (25-30 KTS) VERTICAL WIND SHEAR (VWS), COLD (22-23 C) SEA
SURFACE TEMPERATURES (SST), AND DRY AIR ENTRAINMENT, OFFSET ONLY
SLIGHTLY BE THE STRONG POLEWARD OUTFLOW SUPPORTED BY THE UPPER
LEVEL JET TO THE NORTH. DESPITE THE HIGHLY UNFAVORABLE ENVIRONMENT,
THE 020923Z RCM-1 SAR DATA CONFIRMS THE PRESENCE OF 50-55 KT WINDS
REMAIN PRESENT OVER WATER AND SURROUNDING THE LARGE LLCC IN ALL
QUADRANTS EXCEPT THE SOUTHWEST QUADRANT. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON A COMBINATION OF AGENCY
SATELLITE AND RADAR POSITION FIXES; SURFACE OBSERVATIONS FROM 
WAKAYAMA, TOKUSHIMA, AND KOCHI PREFECTURES; AND THE 021642Z AMSR2 
MICROWAVE IMAGE REVEALING THE POORLY DEFINED LOWER-LEVEL CLOUD 
BANDING. THE INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH MEDIUM 
CONFIDENCE BASED ON THE AFOREMENTIONED SAR DATA IN THE ABSENCE OF 
MORE RECENT RELIABLE WINDSPEED DATA. CIMSS ADT AND AIDT, AND 
SUBJECTIVE DVORAK FIXES ARE ASSESSED TO BE UNDER REPRESENTATIVE OF
THE ACTUAL INTENSITY DUE TO THE LACK OF CENTRAL CONVECTION OVER THE 
SYSTEM.

INITIAL WIND RADII BASIS: PERSISTENCE FROM THE 020923Z SAR DATA

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE SOUTHWEST OF THE SYSTEM

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.5 - 35 KTS
   CIMSS SATCON: 46 KTS AT 021800Z
   CIMSS ADT: 35 KTS AT 021830Z
   CIMSS AIDT: 39 KTS AT 021830Z
   CIMSS D-MINT: 48 KTS AT 021929Z
   CIMSS D-PRINT: 49 KTS AT 021900Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 25-30 KTS
   SST: 22-23 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: SIGNIFICANT DRY AIR ENTRAINMENT IN THE WESTERN
   AND SOUTHERN QUADRANTS

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 06W (JANGMI) IS FORECAST TO CONTINUE
TRACKING NORTHEASTWARD FOR THE DURATION OF THE FORECAST AS IT
TRACKS AROUND THE STR TO ITS SOUTHEAST. TRANSLATIONAL SPEEDS ARE
EXPECTED TO REMAIN ELEVATED WHILE 06W ACCELERATES AROUND THE RIDGE.
06W IS FORECAST TO SKIRT THE COAST OF SOUTHERN JAPAN, MAKING UP TO
THREE LANDFALLS OVER THE NEXT 12 HOURS. JANGMI WILL CONTINUE SLOWLY
UNDERGOING EXTRATROPICAL TRANSITION (ETT) FOR THE NEXT 12 HOURS,
AND BEGIN TO EXHIBIT FRONTAL CHARACTERISTICS NO LATER THAN TAU 24.
AROUND TAU 24, 06W WILL BE FULLY EMBEDDED UNDER THE UPPER-LEVEL
JET. FOLLOWING TAU 24, ETT IS ANTICIPATED TO BE SWIFT, AS THE
COMBINED JET INFLUENCE (INDUCING 30+ KTS VWS AND DRY AIR),
DECREASING SSTS, AND THERMAL ADVECTION ARE EXPECTED TO OVERWHELM
THE SYSTEM. ETT IS FORECAST TO BE COMPLETE NO LATER THAN TAU 36.
REGARDING INTENSITY, 06W WILL MAINTAIN AN INTENSITY OF 50 KTS FOR
THE NEXT 12-24 HOURS, BEFORE SLIGHT WEAKENING AS IT BECOMES
EMBEDDED IN THE JET AND COMPLETES ETT. 

MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN STRONG
AGREEMENT THROUGH TAU 24, BEFORE DIVERGING AT TAU 36. ALL MODELS
EXCEPT ECMWF (GFS, NAVGEM, UKMET, GSM, GALWEM, AND EXPERIMENTAL AI
MODELS) DEPICT A SIGNIFICANT SLOWING OF FORWARD MOTION AND SLIGHT
EASTWARD CURVE. ECMWF MODELS DEPICT A DUE NORTHEASTWARD TRACK AT A
MUCH HIGHER TRANSLATIONAL SPEED, COMPARATIVELY. THE JTWC TRACK
FORECAST IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH OVERALL
HIGH CONFIDENCE. RELIABLE INTENSITY AIDS ARE ALSO IN STRONG
AGREEMENT THAT 06W WILL MAINTAIN A RELATIVELY STABLE INTENSITY OF
AROUND 50 KTS THROUGH TAU 12 BEFORE A SLOW AND STEADY WEAKENING
FROM TAU 12-36. AS A RESULT, THE JTWC INTENSITY FORECAST IS
ASSESSED WITH OVERALL HIGH CONFIDENCE. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
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