WDPN32 PGTW 210300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 15W (PULASAN) 
WARNING NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 33.5N 122.7E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 308 NM WEST-SOUTHWEST OF CHINHAE, SOUTH
KOREA
   MOVEMENT PAST 6 HOURS: EASTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED PROXY VIS AND THE FIRST FEW FRAMES OF VISUAL IMAGERY SHOW
VIGOROUS DEEP CONVECTION PERSISTING OVER THE SOUTHERN SEMICIRCLE OF 
TROPICAL DEPRESSION 15W (PULASAN) WHILE CONFIRMING THAT THE EXTRA-
TROPICAL TRANSITION PROCESS IS NOW WELL UNDERWAY. ALTHOUGH TOPS IN 
ANIMATED ENHANCED INFRARED IMAGERY HAVE COOLED SLIGHTLY, SPECTACULAR 
STREAMERS INDICATIVE OF VIGOROUS CONVECTION ARE SHOOTING OUT OF THE 
MAIN CONVECTIVE REGION TOWARDS THE SOUTHEAST. THE FRONTAL BOUNDARY IN 
THE SOUTHERN WEST SEA IS BECOMING INCREASINGLY INDISCERNIBLE WITH 
PULASAN AND THERE IS INCREASING ASYMMETRY WITHIN THE CORE. 
INTERACTION WITH THE POLAR FRONT JET IS STRETCHING THE SYSTEM AND 
BOOSTING OUTFLOW AT THE MOMENT BUT SOON THAT BOOST WILL BE OVERCOME BY 
AN INCREASING VERTICAL WIND SHEAR. TD 15W IS MOVING OVER A LOCALIZED 
POOL OF COOLER SEA WATER (27C) AND WILL SOON ENTER A STRETCH OF 28-30C 
SEA WATER THAT EXISTS BETWEEN THE VORTEX AND THE SOUTHWEST COAST OF 
KOREA.

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

CURRENT STEERING MECHANISM: THE POLAR FRONT AND THE BAROCLINIC ZONE
BETWEEN THE SOUTHEASTERN MOST FLANK OF THE SUBTROPICAL RIDGE AND THE
JETSTREAM. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   CIMSS ADT: 37 KTS AT 202330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 28 KTS
   SST: 27-30 CELSIUS
   OUTFLOW: MODERATE DUAL-CHANNEL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   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: TD 15W WILL GRADUALLY ACCELERATE AND MERGE
WITH THE POLAR FRONT OVER THE NEXT 24 HOURS. THE SYSTEM WILL HAVE
NEARLY COMPLETED THE PROCESS BY THE TIME IT MAKES LANDFALL ALONG
THE WEST COAST OF HONSHU, NEAR THE NOTO PENINSULA. ONCE IT MOVES
INLAND IT WILL QUICKLY FILL AND BECOME UNTRACKABLE. THERE IS 
INCREASING CERTAINTY THAT THE SYSTEM WILL RIP THROUGH THE PUSAN CHIN 
HAE REGION AT NEAR GALE TO LOW GALE STRENGTH. 

MODEL DISCUSSION: TRACK GUIDANCE IS TIGHT AND HAS BEEN VERY
CONSISTENT. INTENSITY GUIDANCE IS MORE WIDELY VARIED BUT IS
COHERENT WITH THE ETT PROCESS AND LAND INTERACTION. THE JTWC
INTENSITY FORECAST STAYS CLOSE TO HAFS AND THE COAMPS TC BUT DROPS
THE INTENSITY MORE QUICKLY AFTER LANDFALL. 

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