WDPN31 PGTW 200900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 10W (JONGDARI) 
WARNING NR 006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 32.9N 125.4E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 46 NM SOUTHWEST OF JEJU-DO, S. KOREA
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 20 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A SMALL
SYSTEM WITH RAPIDLY COLLAPSING CONVECTION IN AND AROUND THE CENTRAL
DENSE OVERCAST AS EVIDENCED BY FRAGMENTING CONVECTIVE CELLS WITH 
WARMING CLOUD TOPS. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON A WEAK BUT WELL-DEFINED LOW LEVEL CIRCULATION
FEATURE IN THE 200558Z GPM 89GHZ MICROWAVE IMAGE. THE INITIAL
INTENSITY OF 30KTS IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON
RECENT SCATTEROMETRY DATA AND THE MAJORITY OF AGENCY DVORAK
ESTIMATES AND REFLECTS THE 6-HR DECAY. THE INITIAL POSITION AND 
INTENSITY ARE ALSO SUPPORTED BY TRIANGULATION AND EXTRAPOLATION OF 
NUMEROUS NEARBY SURFACE WIND OBSERVATIONS. ANALYSIS INDICATES A 
MARGINALLY UNFAVORABLE ENVIRONMENT WITH WARM SST GREATLY OFFSET BY 
WEAK POLEWARD OUTFLOW AND MODERATE RELATIVE VERTICAL WIND SHEAR.

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

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 42 KTS AT 200408Z
   CIMSS ADT: 37 KTS AT 200540Z
   CIMSS DPRINT: 25 KTS AT 200540Z
   CIMSS DMINT: 27 KTS AT 200553Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 15-20 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: WEAK POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL DEPRESSION 10W WILL ENTER THE YELLOW
SEA AND TRACK NORTHWARD, THEN NORTH-NORTHEASTWARD AS IT ROUNDS THE
WESTERN EDGE OF THE STR, MAKING LANDFALL OVER SOUTHERN NORTH KOREA
NEAR THE DMZ BY TAU 18. THE MARGINALLY UNFAVORABLE ENVIRONMENT WILL
CONTINUE TO GRADUALLY ERODE THE SYSTEM DOWN TO 25KTS BY TAU 12.
AFTER LANDFALL, THE ADDITION OF FRICTIONAL EFFECTS FROM THE RUGGED
TERRAIN WILL LEAD TO DISSIPATION BY TAU 24, LIKELY SOONER. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH AN
EVEN SPREAD TO 120NM BY TAU 24, LENDING HIGH CONFIDENCE TO THE JTWC
TRACK FORECAST. GIVEN THE UNCERTAINTIES OF LAND INTERACTION, I.E.,
THE POSSIBILITY OF EARLY DISSIPATION, THERE IS ONLY MEDIUM
CONFIDENCE IN THE INTENSITY FORECAST. 

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