WDPN32 PGTW 142100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 19W (CHANTHU) 
WARNING NR 035//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.2N 125.4E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 280 NM SOUTHWEST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 11 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE SYSTEM
CONTINUES TO ERODE AS THE ASSOCIATED CONVECTION IS SHEARED, PARTLY
EXPOSING THE LOW LEVEL CIRCULATION (LLC). THERE IS, HOWEVER, FRESH
CONVECTIVE BUILDUP NEAR THE LLC. THE INITIAL POSITION IS PLACED
WITH MEDIUM CONFIDENCE BASED ON THE PARTLY EXPOSED LLC IN EIR. THE
INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON
OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND
EXTRAPOLATED FROM RECENT SCATTEROMETER AND SURFACE OBSERVATION
DATE, AND REFLECTS THE WEAKENED STATE OF THE SYSTEM. ANALYSIS
INDICATES A MARGINAL ENVIRONMENT WITH STRONG POLEWARD OUTFLOW AND
WARM SSTS OFFSET BY MEDIUM TO STRONG VWS. THE SYSTEM IS CURRENTLY
QUASI-STATIONARY IN A COL AREA.

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

CURRENT STEERING MECHANISM: COL BETWEEN SUBTROPICAL RIDGE TO THE
NORTHWEST AND STR TO THE SOUTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T2.5 - 35 KTS
   CIMSS ADT: 35 KTS AT 141740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: CHANGED FORECAST TERMINATION FROM 
EXTRA-TROPICAL TRANSITION TO DISSIPATION AND CUT DOWN TO TAU 48.

FORECAST DISCUSSION: TD 19W IS EXPECTED TO REMAIN QS IN THE COL UP
TO TAU 24. AFTERWARD, THE STR TO THE NORTHWEST WILL WEAKEN AND ALLOW 
THE STR TO THE SOUTHEAST TO ASSUME STEERING AND DRIVE THE CYCLONE 
NORTHEASTWARD. THE MARGINAL ENVIRONMENT WILL SUSTAIN THE CURRENT 
INTENSITY UP TO TAU 24. AFTERWARD, AS THE SYSTEM TRACKS MORE 
POLEWARD, INCREASING VWS AND COOLING SSTS WILL WEAKEN IT TOWARD 
DISSIPATION BY TAU 48, POSSIBLY SOONER.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GENERALLY GOOD AGREEMENT;
HOWEVER, GIVEN THE UNCERTAINTY IN THE STORM MOTION IN THE COL,
THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID
CLOSE TO THE MODEL CONSENSUS.

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