ABPW10 PGTW 172330
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR/HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND/
SOUTH PACIFIC OCEANS REISSUED/172330Z-180600ZJUL2021//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/171951ZJUL2021//
REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/172251ZJUL2021//
NARR/REF A IS A TROPICAL CYCLONE WARNING. REF B IS A TROPICAL/
CYCLONE FORMATION ALERT.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
   A. TROPICAL CYCLONE SUMMARY:
      (1) AT 17JUL21 1800Z, TROPICAL DEPRESSION 09W (IN-FA) WAS 
LOCATED NEAR 22.2N 132.5E, APPROXIMATELY 364 NM SOUTHEAST OF KADENA 
AB, AND HAD TRACKED NORTH-NORTHWESTWARD 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 172100) FOR 
FURTHER DETAILS.
      (2) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) THE AREA OF CONVECTION (INVEST 99W) PREVIOUSLY LOCATED 
NEAR 18.4N 115.4E IS NOW LOCATED NEAR 19.4N 115.4E, APPROXIMATELY 
188 NM SOUTH-SOUTHEAST OF HONG KONG. ANIMATED ENHANCED INFRARED 
SATELLITE IMAGERY DEPICTS BANDING WITH FLARING CONVECTION OVERHEAD. 
A 171805Z AMSR2 89GHZ MICROWAVE IMAGE REVEALS DEVELOPING LOW LEVEL 
BANDING WRAPPING INTO A LOW LEVEL CIRCULATION CENTER (LLCC) WITH 
CONVECTION OVER THE NORTHEAST QUADRANT. A 171225Z ASCAT-A IMAGE 
SHOWS A BROAD CIRCULATION WITH 15-20 KNOT WINDS IN THE NORTHEAST 
QUADRANT. ENVIRONMENTAL ANALYSIS INDICATES FAVORABLE CONDITIONS FOR 
DEVELOPMENT WITH WESTWARD OUTFLOW ALOFT, LOW (10-15 KTS) VERTICAL 
WIND SHEAR, AND WARM (31-32C) SEA SURFACE TEMPERATURES. NUMERICAL 
MODEL GUIDANCE SHOWS INVEST 99W TRACKING NORTHWESTWARD AS IT 
CONSOLIDATES AND INTENSIFIES OVER THE NEXT 24 HOURS. MAXIMUM 
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 13 TO 18 KNOTS. MINIMUM SEA 
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE POTENTIAL FOR 
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 
HOURS IS UPGRADED TO HIGH. SEE REF B (WTPN21 PGTW 172300) FOR 
FURTHER DETAILS.
      (2) NO OTHER SUSPECT AREAS.
   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: NONE.
3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARA 1.B.(1) TO 
HIGH.//
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