WDXS31 PGTW 202100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05S (FINA) WARNING NR 011// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 10.4S 133.0E INITIAL INTENSITY: 60 KTS GEOGRAPHIC REFERENCE: 176 NM NORTHEAST OF DARWIN, AUSTRALIA MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 04 KTS SIGNIFICANT WAVE HEIGHT: 18 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: CONVECTIVE ACTIVITY ASSOCIATED WITH TC 05S CONTINUES TO CYCLE THROUGH PERIODS OF INTENSE DEVELOPMENT FOLLOWED BY GENERAL COLLAPSE. THE MOST RECENT BURST OF ACTIVITY STARTED AROUND 1100Z, PEAKED AROUND 1500Z AND IS NOW MOVING INTO THE COLLAPSE STAGE. CLOUD TOPS HAVE WARMED SIGNIFICANTLY OVER THE PAST COUPLE OF HOURS, PARTICULARLY ALONG THE EASTERN FLANK OF THE SYSTEM, WHERE THE DRIEST MID-LEVEL AIR CONTINUES TO LURK. ANIMATED WATER VAPOR IMAGERY SHOWS A COMPLEX INTERACTION OF FLOW PATTERNS AT DIFFERENT LEVELS OF THE ATMOSPHERE. AT THE OUTFLOW LAYER, STRONG OUTFLOW IS PRESENT, PUSHING OUTWARDS FROM THE CENTER AS EVIDENCED BY THE BROAD ARC OF CIRRUS MOVING TOWARDS THE NORTH AND EAST. HOWEVER, AT A SLIGHTLY LOWER LEVEL, THE WV IMAGERY SHOWS MODERATE NORTHERLY FLOW PUSHING ONTO THE SYSTEM, WHICH ALIGNS WITH THE MODEL-DERIVED SOUNDINGS SUGGESTING MAXIMUM SHEAR AROUND 350MB FROM THE NORTH. THE OVERALL IMPACT IS THAT THE SYSTEM HAS STAGNATED AND FAILED TO INTENSIFY OVER THE PAST DAY OR SO. THE INITIAL POSITION IS ASSESSED WITH MEDIUM CONFIDENCE BASED PRIMARILY ON RADAR DATA, THOUGH THE RADAR DEPICTION IS NEBULOUS AT BEST. AND LATE RECEIPT OF A 201831Z GMI PASS SHOWS A WELL-DEFINED LOW LEVEL CIRCULATION CENTER (LLCC) THOUGH IT DOES NOT ALIGN WELL WITH THE RADAR DATA, AND POST-WARNING REANALYSIS MAY RESULT IN A SHIFT IN THE TRACK NORTHWARD. THE INITIAL INTENSITY IS ASSESSED WITH LOW CONFIDENCE, BASED ON A BLEND OF THE SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES NOTED BELOW. ENVIRONMENTAL CONDITIONS ARE MARGINALLY FAVORABLE, WITH WARM SSTS AND DECENT POLEWARD OUTFLOW OFFSET BY MODERATE NORTHERLY SHEAR, DRY AIR INTRUSION AND VORTEX ASYMMETRIES. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: THE SYSTEM IS STILL BE STEERED THROUGH A WEAK STEERING PATTERN, CAUGHT BETWEEN A STRONG NEAR EQUATORIAL RIDGE (NER) TO THE NORTHEAST WHICH EXTENDS SOUTHWARD OVER THE GULF OF CARPENTARIA, AND A WEAKER NER THAT EXTENDS FROM SOUTH OF JAVA TO THE KIMBERLEY REGION AND A DEVELOPING AREA OF RIDGING CONNECTING THESE TWO TO THE SOUTH AND EAST OF TC 05S. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.5 - 55 KTS ADRM: T3.0 - 45 KTS CIMSS SATCON: 60 KTS AT 201623Z CIMSS ADT: 63 KTS AT 201730Z CIMSS AIDT: 53 KTS AT 201730Z CIMSS D-MINT: 40 KTS AT 201845Z CIMSS D-PRINT: 43 KTS AT 201830Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE POLEWARD OTHER FACTORS: DRY MID-LEVEL AIR ALONG THE EASTERN AND NORTHERN PERIPHERY; VORTEX TILT. ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: LOW INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 05S IS STILL TRAPPED IN A RELATIVELY WEAK STEERING PATTERN, AND THUS IS STILL MOVING RATHER SLOWLY AND ERRATICALLY, BUT GENERALLY TOWARDS THE WEST-SOUTHWEST. OVER THE NEXT 12 TO 18 HOURS, STRONG RIDGING IS EXPECTED TO DEVELOP ALONG THE SOUTHERN COAST OF THE GULF OF CARPENTARIA, AND THIS WILL SERVE TO FINALLY GIVE TC 05S THE KICK IT NEEDS TO TRULY COMMENCE ITS ANTICIPATED SOUTHWESTWARD TRACK. THE STR IS FORECAST TO REMAIN NEARLY QUASI-STATIONARY AND CONTINUE TO BUILD THROUGH THE FORECAST PERIOD, SUPPORTING A SOUTHWESTWARD TRACK FOR THE DURATION. THE SYSTEM IS FORECAST TO CROSS THE VAN DIEMEN GULF OVER THE NEXT 24 HOURS, GRAZE THE COAST IN VICINITY OF DARWIN BETWEEN TAU 36 AND TAU 48 AND THEN MOVE INTO THE JOSEPH BONAPARTE GULF BEFORE MAKING LANDFALL ALONG THE NORTHEAST KIMBERLEY COAST PRIOR TO TAU 96. IN TERMS OF INTENSITY, THE SAME ISSUES THAT WERE PRESENT YESTERDAY REMAIN PROBLEMATIC TODAY, NAMELY VORTEX ASYMMETRY, DRY AIR ALONG THE EASTERN FLANK, AND MODERATE SHEAR ESPECIALLY IN THE MID-LEVELS. THE GFS, ECMWF AND HAFS-A CONTINUE TO INSIST THAT THE SHEAR WILL DROP OFF WITHIN THE NEXT 12 HOURS, DOWN TO LESS THAN 10 KNOTS, WHILE THEY ALSO SHOW A GENERAL MOISTENING OF THE ENVIRONMENT. THIS SHOULD ALLOW FOR A PERIOD OF INTENSIFICATION AS THE SYSTEM MOVES INTO THE VERY WARM WATERS OF THE VAN DIEMEN GULF. WHILE THE SYSTEM WILL SKIRT THE COAST NEAR DARWIN, THE LLCC WILL LIKELY REMAIN OFFSHORE AND THUS THE SYSTEM IS FORECAST TO MAINTAIN INTENSITY AS IT PASSES DARWIN AND MOVES INTO THE BONAPARTE GULF. WHILE THE WATERS IN THE BONAPARTE GULF ARE QUITE WARM, SHEAR AND DRY AIR ARE BOTH ANTICIPATED TO INCREASE AFTER TAU 48, AND THE SYSTEM IS FORECAST TO WEAKEN SLOWLY AS IT CROSSES THE GULF BEFORE LANDFALL. AFTER MAKING LANDFALL IN KIMBERLEY, IT WILL RAPIDLY WEAKEN AND DISSIPATE BY THE END OF THE FORECAST PERIOD. MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS, WITH THE EXCEPTION OF THE GALWEM AND EGRR MODELS, IN GOOD AGREEMENT THROUGH TAU 72. OUTSIDE OF THE MODELS NOTED ABOVE, THE REMAINDER OF THE CONSENSUS PACKAGE IS CONFINED TO AN ENVELOPE THAT EXPANDS TO 75NM BY TAU 72. NAVGEM LIES ON THE EAST AND SOUTH SIDE OF THE ENVELOPE, TRACKING THE SYSTEM EAST OF DARWIN, WHILE THE REMAINDER OF THE MODELS ARE TIGHTLY PACKED NEAR THE MEAN, SKIRTING THE COAST IN THE VICINITY OF DARWIN. AFTER TAU 72, THE MODELS BEGIN TO DIVERGE, WITH THE ECMWF ARCING NORTH OF THE KIMBERLEY COAST AND KEEPING THE CENTER OFFSHORE THROUGH TAU 120, WHILE THE NAVGEM TRACKS THE CENTER TO THE SOUTHEAST OF WYNDHAM, RESULTING IN A 300NM CROSS-TRACK SPREAD BY TAU 120. ENSEMBLE MODELS CONTINUE TO SHOW A FAIRLY LARGE AMOUNT OF UNCERTAINTY, THOUGH THE ENSEMBLE MEANS HAVE COME INTO BETTER AGREEMENT OVERALL, LENDING INCREASING CONFIDENCE TO THE TRACK FORECAST. THE JTWC FORECAST IS PLACED NEAR THE ECMWF AND GDM FGN MEAN THROUGH TAU 72, THEN MORE CLOSELY FOLLOWS THE GFS AND GDM FGN THROUGH TAU 120. INTENSITY GUIDANCE REMAINS SHARPLY MIXED, WITH THE CTCX AND HWRF INDICATING WEAKENING THROUGH THE ENTIRE FORECAST PERIOD, WHILE THE COTC AND HAFS-A INDICATE A RELATIVELY FLAT TREND TO TAU 36 FOLLOWED BY EXTREME RAPID INTENSIFICATION TO PEAKS AT OR ABOVE 130 KNOTS BY TAU 72. HAFS HAS BEEN PERSISTENT IN THIS OVERALL DEPICTION FOR THE LAST SEVERAL MODEL RUNS, THOUGH COAMPS-TC IS A NEWCOMER TO THIS GAME. THAT DOES NOT CHANGE THE FACT THAT THIS SCENARIO REMAINS HIGHLY UNREALISTIC, THOUGH THE OVERALL TREND OF INTENSIFICATION BEYOND TAU 24 IS CONSISTENT WITH THE ECMWF, GFS AND SHIPS GUIDANCE. THE JTWC FORECAST IS PLACED NEAR THE CONSENSUS MEAN THROUGH THE FORECAST PERIOD. FORECAST CONFIDENCE: TRACK 00-72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN