WDPN34 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 09W (WUKONG) WARNING 
NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.8N 149.3E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 333 NM NORTHWEST OF MINAMI TORI SHIMA
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN
ELONGATED LLCC WITH FRAGMENTED CONVECTION ON THE SOUTH SIDE. AN
EARLIER 131126Z ASCAT PASS CONFIRMED THE ELONGATED NATURE OF THE
CIRCULATION, WITH MAX WINDS OF 30 KT ABOUT 100 NM SOUTHEAST OF THE
CENTER. THE INITIAL INTENSITY IS SET AT 30 KT BASED ON THIS DATA,
SUPPORTED BY AGENCY DVORAK INTENSITY ESTIMATES. WESTERLY VERTICAL
SHEAR IS APPARENT, WITH THE UPPER-LEVEL CIRRUS OUTFLOW FROM
TROPICAL STORM 08W STREAMING TOWARDS THE LLCC OF 09W. OVERALL,
SYSTEM ORGANIZATION HAS NOT IMPROVED OVER THE PAST 12 HOURS.

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

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T2.0 - 30 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: DRY AIR MASS TO THE NORTHWEST

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE NEW FORECAST IS SIGNIFICANTLY
FASTER THAN THE PREVIOUS FORECAST IN THE 36-72 HOUR PERIOD DUE TO
MODEL GUIDANCE SHOWING A FASTER MOTION INTO THE MID-LATITUDE
WESTERLIES.

FORECAST DISCUSSION: TROPICAL STORM 09W (WUKONG) IS ELONGATED WITH
A LARGE RADIUS OF MAXIMUM WIND, INDICATING POOR ORGANIZATION.
MODERATE VERTICAL SHEAR IS FORECAST TO IMPACT WUKONG THROUGHOUT THE
NEXT 24 HOURS DUE TO AN UPPER-LEVEL LOW TO THE NORTHWEST, COMBINED
WITH UPPER-LEVEL OUTFLOW FROM 08W. DYNAMICAL MODELS LIKE THE GFS,
HAFS-A, AND HWRF SEEM TO BE OVERZEALOUS IN THE SHORT TERM WITH
WRAPPING DEEP CONVECTION AROUND THE EAST AND NORTH SIDE OF THE
CIRCULATION, AS THIS HAS NOT BEEN OBSERVED YET. AS A RESULT, THE
JTWC INTENSITY FORECAST IS LOWER THAN THESE MODELS, AND SHOWS A
PEAK OF 35 KT DURING THE 12-36 HOUR PERIOD. AFTER 36 HOURS, THE
STORM WILL MOVE OVER COOLER WATERS AND MERGE INTO THE MID-LATITUDE
WESTERLIES. MOST MODELS ARE IN AGREEMENT THAT THE CIRCULATION WILL
OPEN UP INTO A TROUGH AS IT TURNS EASTWARD AND GETS ABSORBED INTO
THE BACKGROUND FLOW SOUTH OF THE JET STREAM. THE JTWC FORECAST THUS
SHOWS DISSIPATION BY 72 HOURS, EVEN AS THE SYSTEM LIKELY RETAINS 25
KT WINDS ON ITS SOUTH SIDE.

MODEL DISCUSSION: THE JTWC TRACK FORECAST IS CLOSE TO THE
MULTI-MODEL CONSENSUS. THE JTWC INTENSITY FORECAST IS CLOSE TO THE
STATISTICAL GUIDANCE, BUT A BIT BELOW DYNAMICAL MODELS LIKE HWRF,
HAFS-A, AND GFS DUE TO THEIR POOR REPRESENTATION OF THE STORM'S
CURRENT STRUCTURE.

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