WDPN32 PGTW 201500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 15W (PULASAN) 
WARNING NR 016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 32.8N 121.1E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 421 NM WEST-SOUTHWEST OF BUSAN, SOUTH
KOREA
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A BROAD,
PARTIALLY-EXPOSED, LOW-LEVEL CIRCULATION (LLC), WITH A LARGE
NEAR-SYMMETRIC AREA OF DEEP CONVECTION OVER WATER TO THE SOUTHEAST.
A 201233Z MHS 89 GHZ MICROWAVE IMAGE SHOWS AN INTENSE CLUSTER OF
DEEP CONVECTION, WITH A WEAKLY DEFINED LLC. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON THE EIR IMAGERY. THE INITIAL
INTENSITY OF 30 KTS IS ASSESSED WITH MEDIUM CONFIDENCE, AND IS
HEDGED SLIGHTLY ABOVE THE AGENCY SUBJECTIVE ESTIMATES BASED ON THE
CIMSS OBJECTIVE ESTIMATES RANGING FROM 32-40 KNOTS.

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

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE SOUTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T1.5 - 25 KTS
   CIMSS ADT: 32 KTS AT 201200Z
   CIMSS AIDT: 40 KTS AT 201200Z
   CIMSS DPRINT: 34 KTS AT 201200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EASTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   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 (TD) 15W HAS REEMERGED
OVER WATER, JUST OFF THE COAST OF CHINA, AND IS EXPECTED TO
ACCELERATE EAST-NORTHEASTWARD THROUGH THE FORECAST PERIOD WITHIN
THE MIDLATITUDE WESTERLIES. THE SYSTEM WILL QUICKLY INTERACT WITH A
STRONG FRONTAL ZONE AND INCREASING UPPER-LEVEL WESTERLIES EXPECTED
TO PUSH INTO SOUTH KOREA OVER THE NEXT 12 HOURS. THIS FRONT IS
EXPECTED TO PRODUCE SIGNIFICANT COLD AIR ADVECTION AND A TIGHT 
PRESSURE GRADIENT ACROSS THE KOREAN PENINSULA AND SEA OF JAPAN. TD
15W WILL TRANSITION INTO A LOW ON THIS FRONTAL BOUNDARY, AND THE
COMBINED EFFECTS OF THE TWO SYSTEMS WILL GENERATE 35-40 KNOT 
SUSTAINED WINDS ACROSS THE COASTAL REGIONS OF SOUTH KOREA, ESPECIALLY 
IN THE 12 TO 24 HOUR PERIOD. TD WILL COMPLETE EXTRA-TROPICAL 
TRANSITION AS IT TRACKS UNDER JET-STRENGTH UPPER-LEVEL WINDS OVER AND 
EAST OF THE KOREAN PENINSULA.      

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT
WITH A 45 NM CROSS-TRACK SPREAD AT TAU 24 NEAR BUSAN. AFTER TAU 24,
NUMERICAL GUIDANCE DIVERGES SLIGHTLY WITH SOME MINOR DIFFERENCES IN
ALONG-TRACK SPEEDS. RELIABLE INTENSITY GUIDANCE REMAINS IN FAIR
AGREEMENT WITH PEAK INTENSITY VALUES RANGING FROM 35-45 KNOTS AT
TAU 24. 

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