ABPW10 PGTW 040600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND SOUTH 
PACIFIC OCEANS/040600Z-050600ZSEP2023//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/040153ZSEP2023//
REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/031352ZSEP2023//
NARR/REF A IS A TROPICAL CYCLONE WARNING. REF B IS A TROPICAL CYCLONE 
FINAL WARNING.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
   A. TROPICAL CYCLONE SUMMARY:
      (1) AT 04SEP23 0000Z, TYPHOON 10W (HAIKUI) WAS LOCATED NEAR 
23.2N 119.8E, APPROXIMATELY 147 NM SOUTHWEST OF TAIPEI, TAIWAN, AND 
HAD TRACKED NORTH-NORTHWESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. 
MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 75 KNOTS GUSTING TO 
90 KNOTS. SEE REF A (WTPN33 PGTW 040300) FOR FURTHER DETAILS.
      (2) AT 03SEP23 1200Z, TROPICAL DEPRESSION 09W (SAOLA) WAS 
LOCATED NEAR 20.7N 109.0E, APPROXIMATELY 175 NM EAST OF HANOI, 
VIETNAM, AND HAD TRACKED SOUTHWESTWARD AT 04 KNOTS OVER THE PAST SIX 
HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 25 KNOTS 
GUSTING TO 35 KNOTS. SEE REF B (WTPN32 PGTW 031500) FOR THE FINAL 
WARNING ON THIS SYSTEM.
      (3) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) AN AREA OF CONVECTION (INVEST 99W) HAS PERSISTED NEAR 20.0N 
129.1E, APPROXIMATELY 390 NM SOUTH-SOUTHEAST OF KADENA, AB. ANIMATED 
MSI AND A 040124Z BULLSEYE ASCAT METOP-C PASS REVEAL A PARTIALLY-
OBSCURED LLC WITH A BAND OF 20-KNOT WINDS EXTENDING FROM THE SOUTH TO 
THE EAST OF THE CENTER AND MOST OF THE CONVECTION SHEARED TO THE 
SOUTH. PRESENTLY, ENVIRONMENTAL CONDITIONS ARE SUBOPTIMAL AS A RESULT 
OF HIGH VWS (20-30KTS) PRESSING DOWN FROM THE NORTH ALONG THE WESTERN 
SIDE OF A STRONG TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) POSITIONED 
TO THE NORTH OF 99W. NONETHELESS, THE WARM SSTS (29-30C) AND AMPLE 
MOISTURE WILL PROVIDE THE ENERGY TO BEGIN THE DEVELOPMENT PROCESS. 
OVER THE NEXT 24 HOURS, THE TUTT WILL WEAKEN AND TRACK NORTHWARD, 
POSITIONING 99W IN THE EASTERN, DIFFLUENT REGION, WHICH WILL SUPPLY 
SUFFICIENT OUTFLOW TO COUNTERACT THE EFFECTS OF THE VWS. THERE IS A 
CONSENSUS ACROSS GLOBAL MODELS THAT CONDITIONS WILL IMPROVE AS INVEST 
99W TRACKS TOWARD THE NORTH-NORTHEAST, WHILE THE HIGH VWS SUBSIDES, 
ENABLING STEADY DEVELOPMENT OVER THE NEXT 72 HOURS. MAXIMUM SUSTAINED 
SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL 
PRESSURE IS ESTIMATED TO BE NEAR 1002 MB. THE POTENTIAL FOR THE 
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS 
IS LOW.
      (2) NO OTHER SUSPECT AREAS.
   C. SUBTROPICAL SYSTEM SUMMARY:
      (1) THE AREA OF CONVECTION (INVEST 98W) PREVIOUSLY LOCATED NEAR 
35.7N 173.5E IS NOW LOCATED NEAR 35.7N 167.3E, APPROXIMATELY 1344 NM 
EAST OF YOKOSUKA, JAPAN. THE SYSTEM IS CURRENTLY CLASSIFIED AS A 
SUBTROPICAL STORM, GENERALLY CHARACTERIZED AS HAVING BOTH TROPICAL AND 
MID-LATITUDE CYCLONE FEATURES. ANIMATED MSI DEPICTS AN ASYMMETRIC 
SYSTEM WITH A FULLY EXPOSED AND WOBBLY LLCC WITH FLARING CONVECTION 
SHEARED TO THE SOUTH. THE ENVIRONMENT IS HIGHLY UNFAVORABLE FOR 
DEVELOPMENT AS THE LLCC IS NOW MOVING DIRECTLY UNDER A STRONG 500MB 
LOW CAUSING UNFAVORABLE (40-50KTS) VWS ACROSS THE LLCC, HINDERING 
OUTFLOW BUT SLIGHTLY OFFSET BY 25-27C SEA TEMPS. GLOBAL MODELS AGREE 
THAT INVEST 98W WILL TRACK GENERALLY WESTWARD, WEAKEN AND GET PICKED 
UP WITHIN THE LONG WAVE PATTERN OVER THE NEXT 72 HOURS. FOR HAZARDS 
AND WARNINGS, REFERENCE THE FLEET WEATHER CENTER SAN DIEGO HIGH WINDS 
AND SEAS PRODUCT OR REFER TO LOCAL WMO DESIGNATED FORECAST AUTHORITY. 
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33 KNOTS. 
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1010 MB. THE 
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN 
THE NEXT 24 HOURS REMAINS LOW.
      (2) NO OTHER SUBTROPICAL SYSTEMS.
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.//
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