WDPN31 PGTW 020300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (JANGMI) WARNING NR 
024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 29.1N 128.5E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 679 NM WEST-SOUTHWEST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 32 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS EXPOSED LOW
LEVEL CIRCULATION (LLC) OF TROPICAL STORM (TS) 06W (JANGMI)
SEPARATED FROM THE UPPER LEVEL CIRCULATION AS IT TRANSITS TOWARDS
THE SOUTH END OF KYUSHU. A 012134Z SAR PASS AND 012210 37 GHZ SSMIS
PASS BOTH SHOW THE CENTER OF TS 06W AS VERY BROAD AND SLIGHTLY
ELONGATED. ENVIRONMENTAL ANALYSIS REVEALS HIGHLY UNFAVORABLE
CONDITIONS AS IT CONTINUES INTO COLDER (24-25 C) SEA SURFACE
TEMPERATURES (SSTS) AND HIGH (25-30 KTS) VERTICAL WIND SHEAR (VWS),
COUPLED WITH DRY AIR ENTRAINMENT AND WEAK POLEWARD OUTFLOW. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
AFOREMENTIONED SAR AND MICROWAVE IMAGES. THE INITIAL INTENSITY IS
ALSO LAID WITH HIGH CONFIDENCE BASED ON THE SAME SAR PASS, CIMSS
OBJECTIVE ESTIMATES, AND AGENCY DVORAK FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) POSITIONED NEAR IWO TO. 


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T3.0 - 45 KTS
   CIMSS SATCON: 46 KTS AT 0030Z
   CIMSS ADT: 33 KTS AT 0100Z
   CIMSS AIDT: 37 KTS AT 0100Z
   CIMSS D-MINT: 48 KTS AT 2210Z
   CIMSS D-PRINT: 40 KTS AT 0100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 25-30 KTS
   SST: 24-25 CELSIUS
   OUTFLOW: WEAK POLEWARD
   OTHER FACTORS: DRY MID-LEVEL AIR ENTRAINING INTO THE
   SOUTHWESTERN FLANK OF THE CIRCULATION. 

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: AS TS JANGMI ROUNDS THE SUBTROPICAL RIDGE
(STR) CENTERED OVER IWO TO AND TURNS NORTHEASTWARD, ITS
TRANSLATIONAL SPEED IS FORECAST TO ACCELERATE AS CORIOLIS FORCE
INCREASES WITH ITS MORE POLEWARD LOCATION. TS 06W IS FORECAST TO
SKIRT THE SOUTHERN COAST OF KYUSHU AND HONSHU, WITH POSSIBLE
LANDFALLS SOUTH OF KYOTO AND YOKOSUKA. INCREASING MID-LEVEL VWS,
DRY AIR ENTRAINMENT, COLD SSTS, AND IMMINENT INTERACTION WITH THE
JET STREAM ALL CONTRIBUTE TO THE FORECAST START OF EXTRATROPICAL
TRANSITION (ETT) BY TAU 36 AND COMPLETING TRANSITION BY TAU 60. IN
LINE WITH THE CONTINUATION OF THESE UNFAVORABLE ENVIRONMENTAL
CONDITIONS, TS 06W IS FORECAST TO GRADUALLY WEAKEN IN INTENSITY
THROUGHOUT THE REMAINDER OF THE FORECAST PERIOD, BUT STAY AT
TROPICAL STORM STRENGTH INTENSITY.

MODEL DISCUSSION: FORECAST TRACK MODEL GUIDANCE IS IN FAIR
AGREEMENT FOR THE REMAINDER OF THE FORECAST PERIOD IN TERMS OF
CROSS TRACK SPREAD, WITH THE LARGEST SPREAD BEING 130 NM AT TAU 60
AS ALL BUT THE INTERPOLATED ECMWF TRACKERS PREDICT A SLIGHT
EAST-SOUTHEAST TURN. THE LARGER AREA OF DISAGREEMENT OCCURS IN THE
ALONG-TRACK SPREAD, WITH SLIGHT DISCREPANCY IN MODEL INTERPRETATION
REGARDING THE MAGNITUDE OF FORWARD ACCELERATION WHEN 06W BEGINS TO
INTERACT WITH THE JET, RESULTING IN A 150 NM ALONG-TRACK SPREAD AT
TAU 60. THE OFFICIAL JTWC TRACK FORECAST IS STILL PLACED WITH HIGH
CONFIDENCE, IN LINE WITH THE MULTI-MODEL CONSENSUS. THE OFFICIAL
JTWC INTENSITY FORECAST IS ASSESSED WITH MEDIUM CONFIDENCE,
SLIGHTLY ABOVE THE MULTI-MODEL CONSENSUS BUT BELOW THE MESOSCALE
MODELS.

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