ABPW10 PGTW 082000 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND /SOUTH PACIFIC OCEANS REISSUED/082000Z-090600ZOCT2021// REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/081351ZOCT2021// REF/B/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/081521ZOCT2021// REF/C/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/081721ZOCT2021// NARR/REF A IS A TROPICAL CYCLONE WARNING. REFS B AND C ARE TROPICAL CYCLONE FORMATION ALERTS.// RMKS/ 1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA): A. TROPICAL CYCLONE SUMMARY: (1) AT 08OCT21 1200Z, TROPICAL STORM 22W (LIONROCK) WAS LOCATED NEAR 19.0N 110.3E, APPROXIMATELY 276 NM EAST-SOUTHEAST OF HANOI, VIETNAM, AND HAD TRACKED NORTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 40 KNOTS GUSTING TO 50 KNOTS. SEE REF A (WTPN31 PGTW 081500) FOR FURTHER DETAILS. (2) NO OTHER TROPICAL CYCLONES. B. TROPICAL DISTURBANCE SUMMARY: (1) THE AREA OF CONVECTION (INVEST 93W) PREVIOUSLY LOCATED NEAR 12.4N 131.3E IS NOW LOCATED NEAR 12.6N 131.9E, APPROXIMATELY 951 NM NORTH-NORTHWEST OF PALAU. THIS SYSTEM IS CURRENTLY CLASSIFIED AS A MONSOON DEPRESSION WITH EXPANSIVE GALE-FORCE WINDS OVER THE EASTERN PERIPHERY OF THE SYSTEM. THE GALE FORCE WINDS ARE LOCATED OVER 300NM FROM THE BROAD, POORLY-DEFINED SYSTEM CENTER. AS IS TYPICAL WITH MONSOON DEPRESSIONS, ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 080928Z SSMIS 91GHZ MICROWAVE IMAGE DEPICT EXTENSIVE AREAS OF INTENSE DEEP CONVECTION OVER THE WESTERN, SOUTHERN AND EASTERN PERIPHERIES WITH NO CENTRAL CONVECTION OVER THE BROAD, POORLY-DEFINED LOW-LEVEL CIRCULATION. A 081025Z ASCAT-A PARTIAL IMAGE REVEALS AN ELONGATED, WEAK CIRCULATION WITH 20-25 KNOT WESTERLY WINDS OVER THE SOUTHERN SEMICIRCLE AND SHARP TROUGHING EXTENDING NORTHEASTWARD INTO INVEST 94W, WHICH IS ROTATING AROUND THE PERIPHERY OF INVEST 93W. UPPER-LEVEL ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH CONVERGENT NORTHERLY FLOW OVER THE LLC AND LOW TO MODERATE (10-20 KTS) VERTICAL WIND SHEAR. GLOBAL MODELS INDICATE THAT THIS MONSOON DEPRESSION WILL STEADILY STRENGTHEN AS IT TRACKS NORTHWARD TO NORTHWESTWARD OVER THE NEXT TWO DAYS. THE SYSTEM IS EXPECTED TO GRADUALLY GAIN TROPICAL CYCLONE (WARM-CORE) CHARACTERISTICS WITH IMPROVED CENTRAL CONVECTION AND A RADIUS OF MAXIMUM WINDS LESS THAN 100NM. BASED ON THE PERIPHERAL WINDS IN RECENT ASCAT IMAGERY, 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 HIGH. SEE REF B (WTPN21 PGTW 081530) FOR FURTHER DETAILS. (2) THE AREA OF CONVECTION (INVEST 94W) PREVIOUSLY LOCATED NEAR 15.6N 137.1E IS NOW LOCATED NEAR 17.2N 133.5E, APPROXIMATELY 680 NM EAST OF APARRI, PHILIPPINES. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH CONVECTION DISPLACED >90NM TO THE EAST, EXTENDING EQUATORWARD. A 081657Z AMSR2 89GHZ SATELLITE IMAGE REVEALS LOW LEVEL CLOUD LINES WRAPPING INTO THE LLCC, AND AN OVERALL ABSENCE OF ORGANIZATION TO THE DEEP CONVECTION ASSOCIATED WITH THE SYSTEM. INVEST 94W IS CURRENTLY EMBEDDED IN A BROAD MONSOON DEPRESSION WITH LIGHT (<15 KNOTS) WINDS NEAR THE CENTER, AND A LARGE SWATH OF 25-30 KT WINDS DISPLACED >60 NM TO THE EAST. UPPER-LEVEL ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH ROBUST POLEWARD OUTFLOW ALOFT OVER THE MAIN CONVECTION, AND MODERATE TO HIGH (20-30 KTS) VERTICAL WIND SHEAR. SEA SURFACE TEMPERATURES (SST) ARE FAVORABLE WITH WARM (30-31C) AND HIGH OCEAN HEAT CONTENT (>100 KJ PER SQUARE CM). GLOBAL MODELS INDICATE THAT THE TWO DOMINANT VORTEX CENTERS EMBEDDED IN THE MONSOON DEPRESSION (INVESTS 93W AND 94W) WILL STEADILY ORBIT ONE ANOTHER AND MERGE DUE TO THEIR CLOSE PROXIMITY (ABOUT 250 NM). DURING THIS CONSOLIDATION PHASE, THE SYSTEM IS EXPECTED TO GRADUALLY GAIN TROPICAL CYCLONE (WARM-CORE) CHARACTERISTICS WITH IMPROVED CENTRAL CONVECTION AND A RADIUS OF MAXIMUM WINDS LESS THAN 100NM. NUMERICAL MODELS FURTHER AGREE ON A SLOW, GENERALLY NORTHWESTWARD TRACK OVER THE NEXT 24 TO 48 HOURS. IT REMAINS UNCLEAR WHICH STORM WILL GAIN THE DOMINANT CENTER. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO HIGH. SEE REF C (WTPN22 PGTW 081930) FOR FURTHER DETAILS. (3) THE AREA OF CONVECTION (INVEST 95W) PREVIOUSLY LOCATED NEAR 14.5N 166.5E IS NOW LOCATED NEAR 14.8N 166.0E, APPROXIMATELY 272 NM SOUTH OF WAKE ISLAND. ANIMATED EIR SATELLITE IMAGERY DEPICTS A BROAD LOW LEVEL CIRCULATION OBSCURED BY PERSISTENT CONVECTION OVERHEAD. A 081704Z SSMIS 91GHZ SATELLITE IMAGE REVEALS AN OVERALL LACK OF CONVECTIVE STRUCTURE. ENVIRONMENTAL ANALYSIS INDICATES MARGINAL CONDITIONS FOR DEVELOPMENT CHARACTERIZED BY WARM (29-30C) SST OFFSET BY LIMITED OUTFLOW ALOFT AND LOW TO MODERATE (10-20 KT) VWS. NUMERICAL MODELS ARE IN GENERAL AGREEMENT THAT INVEST 95W WILL TRACK WEST-NORTHWESTWARD AND INTENSIFY OVER THE NEXT 24 TO 48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1008 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS MEDIUM. (4) 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.(2) TO HIGH.// NNNN