WDPN31 PGTW 192100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (JONGDARI) WARNING NR 
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 29.2N 125.5E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 387 NM SOUTH-SOUTHWEST OF CHINHAE, SOUTH
KOREA
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS FLARING
CONVECTION PARTIALLY OBSCURING A WEAK LOW-LEVEL CIRCULATION CENTER
(LLCC) AS TROPICAL STORM (TS) 10W IS FIGHTING MODERATE 15-20KT
VERTICAL WIND SHEAR (VWS). WATER VAPOR IMAGERY DEPICTS WEAK RADIAL
OUTFLOW DUE TO CLOSE PROXIMITY TO AN UPPER-LEVEL JET TO THE NORTH.
WHILE THE CIRCULATION CENTER IS NOT LOCATED WITHIN RANGE OF A
RADAR, WEAK CLOUD BANDING ON THE WESTERN AND SOUTHERN PERIPHERY
ROTATE CYCLONICALLY AROUND THE CIRCULATION CENTER. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED
ANIMATED EIR. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE AGENCY AND OBJECTIVE FIXES LISTED
BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: ON THE WESTERN PERIPHERY OF A
SUBTROPICAL RIDGE TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T2.5 - 35 KTS
   CIMSS SATCON: 34 KTS AT 191740Z
   CIMSS ADT: 27 KTS AT 191730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 15-20 KTS
   SST: 31-32 CELSIUS
   OUTFLOW: WEAK RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 10W IS FORECAST TO TRACK DUE NORTH OVER THE
NEXT 12 HOURS WHILE UNDER THE STEERING INFLUENCE OF A STR TO THE
EAST. AFTER TAU 12, THE SYSTEM WILL TRACK NORTH-NORTHEASTWARD AS IT
BEGINS TO ROUND THE RIDGE AND WILL CONTINUE TRACKING JUST NORTH OF
THE GYEONGGI-DO REGION OF SOUTH KOREA THROUGH THE END OF THE FORECAST
PERIOD. WEAKENING WILL COMMENCE WITHIN THE NEXT TWELVE HOURS AS THE
CIRCULATION REMAINS UNDER MODERATE (10-15KT) VERTICAL WIND SHEAR
AND THE UPPER-LEVEL ENVIRONMENT BECOMES UNFAVORABLE. AS THE TS
CONTINUES ON AN OVERALL NORTH-NORTHEASTWARD TRACK, IT WILL BECOME
EMBEDDED UNDER AN UPPER-LEVEL JET, THEREBY SHALLOWING THE VORTEX OF
THE SYSTEM AND CAUSING THE UPPER-LEVEL FLOW TO BECOME STREAMLINED.
ONCE MAKING LANDFALL BETWEEN TAU 24 AND 36, TS 10W WILL DISSIPATE
OVER LAND AS IT INTERACTS WITH THE MOUNTAINOUS TERRAIN OF THE
KOREAN PENINSULA.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
THAT TS 10W WILL TRACK NORTH-NORTHEAST WHILE UNDER THE STEERING
INFLUENCE OF THE STR. FEW TRACKERS (NAVGEM, GSM) DEPICT SOLUTIONS
THAT TRACK NEARLY DUE NORTH, BUT THE JTWC FORECAST LIES CLOSELY TO
THE MULTI-MODEL CONSENSUS MEAN. FURTHER SUPPORT FOR A MORE
NORTH-NORTHEASTWARD TRACK CAN BE FOUND IN THE MODEL SOLUTIONS OF
GEFS AND ECENS, WHICH BOTH TRACK NORTH-NORTHEASTERLY AS WELL. THE
INTENSITY GUIDANCE IS IN GOOD AGREEMENT THAT THE SYSTEM WILL WEAKEN
AS IT APPROACHES LAND BUT DOES NOT COMPLETELY DISSIPATE OVER LAND.
THE JTWC FORECAST WEAKENS THE CIRCULATION MORE QUICKLY THAN THE
MULTI-MODEL CONSENSUS DUE TO THE ANTICIPATED TOPOGRAPHIC
INTERACTION WITH THE MOUNTAINS OF NORTH KOREA. THE ENSEMBLE
GUIDANCE INDICATES A POSSIBILITY THAT THE SYSTEM MAY DISSIPATE
PRIOR TO LANDFALL DUE TO VARYING INTERPRETATIONS OF HOW STRONGLY
THE UPPER-LEVEL JET IMPACTS THE TS, CONTRIBUTING TO THE MEDIUM
CONFIDENCE IN THE JTWC INTENSITY FORECAST.

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