WDPN32 PGTW 052100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 13W (BAILU) WARNING 
NR 016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 39.7N 160.4E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 881 NM EAST OF MISAWA, JAPAN
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL DEPRESSION 13W (BAILU) CONTINUES ITS LONG SLOW MERGE INTO
THE POLAR FRONT. ANIMATED ENHANCED INFRAED IMAGERY SHOWS COLD AIR
STRATOCUMULUS FIELDS AND DRY NORTHWESTERLIES PENETRATING INTO THE
SOUTHEASTERN QUADRANT AND COLD FRONTOGENESIS BECOMING ESTABLISHED
OVER THE SOUTHERN SEMICIRCLE, BUT THE EXPOSED LOW-LEVEL CIRCULATION
CENTER IS MAINTAINING A TIGHT WRAP. THE CORE OF THE SYSTEM IS
CROSSING THE 26C SST ISOTHERM AND HAS LOST SUPPORT FROM BOTH ABOVE
AND BELOW. THE JTWC FIX AND A 051529Z AMSR2 SERIES GIVES GOOD
CONFIDENCE TO PLACEMENT, AND RCTP, RJTD, AND PGTW DVORAKS ALL ALIGN ON
A 25KT INTENSITY. A 051056Z SCATTEROMETRY PASS ALSO CONFIRMED THE
INTENSITY. THE SYSTEM IS POLEWARD OF THE SUBTROPICAL RIDGE BUT THE
VIGOROUS WESTERLIES ASSOCIATED WITH THE POLAR FRONT JET ARE WELL
NORTH OF THE 45TH LATITUDE. THE TRAJECTORY OF THE STORM IN RELATION TO
THE JET IS BECOMING MORE PARALLEL, SO THE TRANSITION TO AN
EXTRA-TROPICAL CYCLONE WILL BE GRADUAL.

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

CURRENT STEERING MECHANISM: THE NORTHERN PERIMETER OF THE
SUBTROPICAL RIDGE AND THE EXTREME EQUATORWARD FLANK OF THE POLAR
FRONT JET. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T1.5 - 25 KTS
   RCTP: T1.5 - 25 KTS
   CIMSS SATCON: 40 KTS AT 051700Z
   CIMSS ADT: 25 KTS AT 051740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 10-15 KTS
   SST: 19-20 CELSIUS
   OUTFLOW: WEAK 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: IT WILL BE ANOTHER 18 TO 24 HOURS BEFORE TD
13W FULLY FINISHES EXTRA-TROPICAL TRANISTION. IN THE MEANTIME, IT
WILL TRACK NORTHEASTWARD AT A STEADY PACE AS MAKES ITS GRADUAL
TRANSITION INTO THE POLAR FRONT.  

MODEL DISCUSSION: TRACK GUIDANCE IS VERY TIGHT-THE MULTI MODEL
CONSENSUS WORKS FINE FOR THIS SYSTEM. BOTH STATISTICAL-DYNAMICAL
AND MESO-SCALE GUIDANCE SUCH AS HAFS-A SHOW A STEADY DECLINE IN
INTENSITY WITH NO FLARE UP INTO A SEVERE BAROCLINIC LOW AS THE
SYSTEM BECOMES EXTRA-TROPICAL. 

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