WDPS31 PGTW 070900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 30P (MAILA) WARNING NR 010// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 9.9S 156.5E INITIAL INTENSITY: 100 KTS GEOGRAPHIC REFERENCE: 668 NM SOUTH OF KAPINGAMARANGI MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 01 KTS SIGNIFICANT WAVE HEIGHT: 32 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN EASILY IDENTIFIABLE, SLIGHTLY IRREGULAR EYE FEATURE OF TROPICAL CYCLONE (TC) 30P (MAILA). SINCE THE LAST WARNING, THE EYE TEMPERATURE HAS INCREASED 16 DEGREES C (TO A CURRENT ESTIMATE OF 9 C), WHILE THE CLOUD TOPS REMAINED COLD AT -83 C. SIGNIFICANT CONSOLIDATION OCCURRED, WITH THE MORE SYMMETRICAL EYEWALL NOW PRESENT WITHIN ALL QUADRANTS. THE ENVIRONMENTAL ANALYSIS REVEALS MOSTLY FAVORABLE CONDITIONS WITH LOW TO MODERATE (15-20 KTS) VERTICAL WIND SHEAR (VWS), PLENTY OF MOISTURE AVAILABLE THROUGHOUT THE ATMOSPHERIC COLUMN, AND A GOOD, PRIMARILY WESTWARD, OUTFLOW CHANNEL. THE ONLY FACTOR POTENTIALLY CAPPING THE RATE OF INTENSIFICATION IS THE EFFECT OF COLD WATER UPWELLING DEPICTED BY COUPLED MESOSCALE MODELS (HAFS AND HWRF). THE IMPACT OF THAT HOWEVER, SEEMS NOT TO BE SIGNIFICANT ENOUGH AT THE MOMENT TO RESULT IN ANY FORM OF WEAKENING, AS WITNESSED BY IMPROVED CONVECTIVE STRUCTURE, SYMMETRY, AND WARMING EYE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON VISIBLE SATELLITE IMAGERY AND THE INITIAL INTENSITY OF 100 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE COMBINATION OF AGENCY DVORAK FIXES AND AUTOMATED ESTIMATES LISTED BELOW COLLECTIVELY INDICATING INTENSIFICATION SINCE THE PREVIOUS FORECAST. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED OVER AUSTRALIA TO THE SOUTHWEST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T6.0 - 115 KTS KNES: T6.5 - 127 KTS ABRF: T5.5 - 102 KTS CIMSS SATCON: 97 KTS AT 070259Z CIMSS ADT: 102 KTS AT 070540Z CIMSS AIDT: 98 KTS AT 070630Z CIMSS D-MINT: 119 KTS AT 070715Z CIMSS D-PRINT: 106 KTS AT 070800Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 10-15 KTS SST: 24-29 CELSIUS OUTFLOW: MODERATE WESTWARD OTHER FACTORS: COOL WATER UPWELLING RESULTING IN SLOW TRANSLATIONAL SPEEDS IN VICINITY OF THE CURRENT TRACK ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: PREVIOUSLY ASSESSED SLIGHT WEAKENING TREND OVER THE NEXT 24 HOURS HAS SHIFTED INTO A POTENTIAL FOR INTENSIFICATION, WITH PEAK INTENSITY NOW ESTIMATED AT AROUND 115-120 KTS. FORECAST DISCUSSION: TC 30P IS FORECAST TO REMAIN NEARLY STATIONARY OVER THE NEXT 12-24 HOURS, WHILE SLOWLY RESPONDING TO THE STEERING MECHANISM FROM THE STR CENTERED TO THE SOUTHWEST. AFTER TAU 24, THE SYSTEM IS EXPECTED TO BEGIN ACCELERATING AS IT TRACKS WEST- SOUTHWESTWARD JUST SOUTH OF THE PAPUAN PENINSULA. THE CURRENT FORECAST ENDS BEFORE TC 30P APPROACHES THE QUEENSLAND COASTLINE. INTENSITY FORECAST CONFIDENCE REMAINS LOW, DUE TO THE UNCERTAINTY ASSOCIATED WITH UPWELLING EFFECTS MENTIONED EARLIER. HAFS AND HWRF DEPICT A RELATIVELY BROAD POOL OF SUB-26 DEGREE WATER IN CLOSE PROXIMITY TO THE CURRENT POSITION OF THE LOW-LEVEL CIRCULATION CENTER (LLCC). AVAILABLE SATELLITE IMAGERY INDICATES THAT THE SYSTEM CONTINUES TO INTENSIFY, EITHER DUE TO THE COLD WATER POOL BEING SMALLER THAN DEPICTED, THE TRACK BEING FAR ENOUGH, OR THE SEA SURFACE TEMPERATURES BEING HIGHER THAN PREDICTED BY THE COUPLED MESOSCALE MODELS. WITH OTHER ENVIRONMENTAL PARAMETERS BEING MOSTLY FAVORABLE, TC 30P IS FORECAST TO CONTINUE INTENSIFYING AND REACHING AROUND 115 KTS BETWEEN TAUS 36 AND 48. AFTER THAT, TC MAILA IS EXPECTED TO START WEAKENING DUE TO INCREASING MID-LEVEL VERTICAL WIND SHEAR (REACHING AS HIGH AS 35-40 KTS AROUND TAU 72) AND POTENTIAL FRICTIONAL EFFECTS OF LAND INTERACTION WITH THE OWEN STANLEY MOUNTAINS, IF THE SYSTEM PASSES CLOSE ENOUGH. MODEL DISCUSSION: NUMERICAL TRACK MODEL GUIDANCE IS ASSESSED WITH MEDIUM CONFIDENCE AND IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS. THE MID-POINT BETWEEN THE FASTER DETERMINISTIC AND ENSEMBLE GFS, AVERAGE ECMWF ENSEMBLE, AND SLOWEST UKMET, NAVGEM AND GALWEM. WHILE ALL MODELS AGREE ON THE GENERAL STEERING PATTERN AND A WESTWARD, FOLLOWED BY A WEST-SOUTHWESTWARD TRACK, THE TIMELINE OF THE INITIAL TURN AS WELL AS THE ACCELERATION AFTERWARDS REMAINS HIGHLY UNCERTAIN. AN ADDITIONAL WRINKLE IN THE GUIDANCE IS INTRODUCED BY THE LAND INTERACTION EFFECTS, ONLY IF THE SYSTEM TAKES A TRACK CLOSER TO PAPUA NEW GUINEA. REGARDING INTENSITY, A RECENT SHIFT IN THE INTENSIFICATION TREND, WITNESSED BY THE SIGNIFICANT EYEWALL AND AN OVERALL CONVECTIVE CONSOLIDATION MATCHED BY NEARLY ALL AVAILABLE GUIDANCE POINTING TOWARDS STRENGTHENING OF THE SYSTEM AT LEAST UNTIL THE INCREASE IN THE MID-LEVEL SHEAR. THE OFFICIAL JTWC INTENSITY FORECAST IS ONLY ASSESSED WITH LOW CONFIDENCE DUE TO HIGH UNCERTAINTY ASSOCIATED WITH THE IMPACTS (OR LACK OF THEREOF) FROM THE COLD WATER UPWELLING INDICATED BY HAFS AND HWRF, AS WELL AS A LARGE ALONG-TRACK SPREAD. ADDITIONALLY, NUMEROUS RAPID INTENSIFICATION AIDS WERE TRIGGERED DURING THE MOST RECENT MODEL RUN, AND FURTHER POINTS TOWARDS A CONSOLIDATION AND AN INTENSIFICATION TREND. FORECAST CONFIDENCE: TRACK 00-72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 00-72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN