ABPW10 PGTW 210600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS/210600Z-220600ZDEC2020//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/210151ZDEC2020//
AMPN/REF A IS A TROPICAL CYCLONE WARNING.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
   A. TROPICAL CYCLONE SUMMARY:
      (1) AT 21DEC20 0000Z, TROPICAL DEPRESSION 26W (KROVANH) WAS 
LOCATED NEAR 9.6N 113.6E, APPROXIMATELY 414 NM EAST OF HO CHI MINH 
CITY, VIETNAM, AND HAD TRACKED WEST- SOUTHWESTWARD AT 06 KNOTS OVER 
THE PAST SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED 
AT 30 KNOTS GUSTING TO 40 KNOTS. SEE REF A (WTPN31 PGTW 210300) FOR 
FURTHER DETAILS.
      (2) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY: NONE.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
   A. TROPICAL CYCLONE SUMMARY: NONE.
   B. TROPICAL DISTURBANCE SUMMARY: NONE.
   C. SUBTROPICAL SYSTEM SUMMARY:
      (1) THE AREA OF CONVECTION (REMNANTS OF 05P) PREVIOUSLY 
LOCATED NEAR 23.9S 178.7E IS NOW LOCATED NEAR 24.8S 179.1E, 
APPROXIMATELY 305 NM SOUTHWEST OF TONGA. THE SYSTEM IS CURRENTLY 
CLASSIFIED AS A SUBTROPICAL STORM, GENERALLY CHARACTERIZED AS HAVING 
BOTH TROPICAL AND MID-LATITUDE CYCLONE FEATURES. ANIMATED 
MULTISPECTRAL SATELLITE IMAGERY (EIR), SUPPORTED BY A 210430Z SSMI F-
15 85GHZ MICROWAVE IMAGE, DEPICTS A FULLY EXPOSED LOW LEVEL 
CIRCULATION CENTER (LLCC) WITH AN ASYMMETRIC OVERALL CONVECTIVE 
STRUCTURE AND THE MAJORITY OF THE DEEP CONVECTION OFFSET TO THE 
SOUTH. A 202142Z METOP-B ASCAT PASS REVEALS A THE TIGHT LLCC 
SURROUNDED BY 20 TO 25 KNOT WINDS TO THE NORTH AND A LARGE AREA OF 
30 TO 35 KNOT WINDS TO THE SOUTH. THE VERTICAL CROSS-SECTION 
TEMPERATURE ANOMALY REVEALS A SURFACE WARM CORE BENEATH A COOL UPPER 
LEVEL CORE, FURTHER SUPPORTING THE CLASSIFICATION AS A SUBTROPICAL 
SYSTEM. THE REMNANTS OF 05P ARE CURRENTLY IN AN ENVIRONMENT 
UNFAVORABLE FOR TROPICAL DEVELOPMENT WITH EXCELLENT POLEWARD OUTFLOW 
BEING HEAVILY OFFSET BY UNFAVORABLE (40 TO 50 KNOT) VERTICAL WIND 
SHEAR AND COOL (<25 CELSIUS) SEA SURFACE TEMPERATURES. GLOBAL MODELS 
ARE IN GOOD AGREEMENT THAT THE REMNANTS OF 05P WILL TRACK SOUTH-
SOUTHWESTWARD WHILE WEAKENING, EVENTUALLY DISSIPATING IN THE NEXT 
SEVERAL DAYS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 30 TO 
35 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 996 MB. 
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE 
WITHIN THE NEXT 24 HOURS REMAINS LOW.
      (2) NO OTHER SUSPECT AREAS.//
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