WDIO31 PGTW 070300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (BIPARJOY) WARNING NR 004// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 12.5N 66.3E INITIAL INTENSITY: 75 KTS GEOGRAPHIC REFERENCE: 641 NM SOUTHEAST OF MASIRAH ISLAND MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 02 KTS SIGNIFICANT WAVE HEIGHT: 22 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS BANDS OF PULSING CONVECTION, FIRING OFF TO THE SOUTHWEST OF THE LOW LEVEL CIRCULATION CENTER (LLCC) AND WRAPPING UPSHEAR TO THE EAST. ANIMATED IMAGERY FROM THE 0200Z HOUR HOWEVER SUGGESTS THAT THE MOST RECENT CONVECTIVE BURST HAS COLLAPSED, CLOUD TOP TEMPERATURES HAVE WARMED CONSIDERABLY AND THE MESOSCALE UPPER-LEVEL OUTFLOW FRONT HAS BEEN PUSHED BACK TOWARDS THE CORE OF THE SYSTEM. ANOTHER ROUND OF NASCENT CONVECTIVE TOWERS IS FLARING AGAIN ALONG THE SOUTHERN SIDE OF THE CENTER, BUT IT REMAINS TO BE SEEN WHAT IMPACT THIS WILL HAVE AS CONVECTIVE MAXIMUM APPROACHES. A TIMELY 062320Z SSMIS 91GHZ MICROWAVE IMAGE REVEALED A SMALL MICROWAVE EYE FEATURE, WITH A WIDE EXPANSE OF CONVECTIVE BANDS EXTENDING TO THE SOUTHWEST, BUT ONLY MINIMAL CONVECTIVE BANDING TO THE NORTHERN SIDE. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE ABOVE MENTIONED MICROWAVE IMAGERY. MEANWHILE THE INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE, HEDGED HIGHER THAN THE DVORAK CURRENT INTENSITY ESTIMATES BASED ON A PGTW DATA-T OF T4.5 (77 KNOTS), SUPPORTED BY THE ADT AND AIDT ESTIMATES OF 75 KNOTS AND 72 KNOTS RESPECTIVELY AND A DMINT ESTIMATE OF 71 KNOTS. MODERATE TO HIGH EASTERLY SHEAR IS PUTTING A BRAKE ON RAPID DEVELOPMENT, AS CONVECTION WILL PULSE AND PUSH BACK AGAINST THE SHEAR, THEN COLLAPSE AND START THE PROCESS ONCE MORE. OTHERWISE, CONDITIONS ARE GENERALLY FAVORABLE WITH VERY WARM SSTS, HIGH OHC AND GOOD EQUATORWARD AND POLEWARD OUTFLOW. THE SYSTEM CONTINUES TO DRIFT SLOWLY POLEWARD, WITH AN EXTENSION OF THE SUBTROPICAL RIDGE (STR) ALONG 20N BLOCKING SIGNIFICANT POLEWARD MOVEMENT FOR THE MOMENT. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: NEAR EQUATORIAL RIDGE (NER) TO THE SOUTH AND EXTENSION OF THE STR TO THE NORTH WHICH IS BLOCKING POLEWARD MOVEMENT. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.0 - 65 KTS KNES: T4.0 - 65 KTS DEMS: T3.0 - 45 KTS CIMSS SATCON: 58 KTS AT 062135Z CIMSS ADT: 75 KTS AT 070030Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 20-25 KTS SST: 30-31 CELSIUS OUTFLOW: MODERATE POLEWARD AND EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH 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 02A CONTINUES TO DRIFT VERY SLOWLY TOWARDS THE NORTH-NORTHEAST UNDER A BLOCKING PATTERN, WITH A FAIRLY ROBUST DEEP-LAYER RIDGE EXTENSION LYING ACROSS ITS PATH TO THE NORTH. AS A MID-LATITUDE TROUGH PUSHES EAST INTO NORTHERN INDIA OVER THE NEXT 12 TO 24 HOURS, THE BLOCKING RIDGE TO THE NORTH IS EXPECTED TO ERODE AND ULTIMATELY BREAK. AT THE SAME TIME, A NEW DEEP-LAYER RIDGE IS EXPECTED TO DEVELOP OVER SOUTHERN INDIA BY TAU 24, WHICH WILL BUILD STEADILY NORTH AND NORTHWESTWARD THROUGH THE REMAINDER OF THE FORECAST PERIOD. THE NET EFFECT OF THESE CHANGES IN THE STEERING PATTERN WILL BE THAT TC 02A DRIFTS SLOWLY NORTHWARD THROUGH ABOUT TAU 36, THEN WILL PICK UP SOME SPEED AND SLOWLY BUT STEADILY LEAN OVER TO THE LEFT, ENDING UP ON A NORTH-NORTHWESTWARD TRACK BY THE END OF THE FORECAST PERIOD. THE INTENSITY FORECAST IS ENTIRELY DEPENDENT UPON THE ABILITY OF THE DEEP CONVECTION TO CONTINUE TO WRAP UPSHEAR, BUT MORE IMPORTANTLY, THE SUSTAIN ITSELF THERE. ASSUMING THIS WILL BE ABLE TO HAPPEN AS WE APPROACH CONVECTIVE MAXIMUM, THE FORECAST CALLS FOR A PERIOD OF NEAR-RAPID INTENSIFICATION, TO A PEAK OF 100 KNOTS BY TAU 36. AFTER TAU 36, CHANGES TO THE UPPER-LEVEL PATTERN INDICATE THE SYSTEM WILL BE CUT OFF FROM THE EQUATORWARD OUTFLOW CHANNEL AND FOR AT TIME, OUTFLOW WILL BE SIGNIFICANTLY CONSTRAINED, LEADING TO A PERIOD OF STAGNANT INTENSITY THROUGH ABOUT TAU 48. THEREAFTER, AN EXPECTED INCREASE IN EASTERLY SHEAR AND DRY AIR ENTRAINMENT FROM THE ARABIAN PENINSULA WILL COMPOUND THE IMPACT OF THE REDUCED UPPER-LEVEL OUTFLOW, LEADING TO A MORE PRONOUNCED WEAKENING TREND THROUGH THE REMAINDER OF THE FORECAST PERIOD. MODEL DISCUSSION: TRACK GUIDANCE IS COMING INTO BETTER AGREEMENT, AND THOUGH WHILE STILL BIFURCATED, THE SPREAD BETWEEN THE OUTLIERS HAS DECREASED WITH THIS RUN. THE GENERAL SCENARIO REMAINS THE SAME, WITH THE UKMET, GALWEM AND THEIR ENSEMBLES TAKING THE SYSTEM DUE NORTH THROUGH THE FORECAST PERIOD, WHILE THE GFS, NAVGEM, ECMWF, GEFS AND ECENS ALL TAKE THE SYSTEM MORE TOWARDS THE NORTHWEST. MEANWHILE THE HWRF AND COAMPS-TC MEMBERS ARE THE EXTREME OUTLIERS TO THE WEST, TAKING THE SYSTEM SHARPLY WESTWARD TOWARDS SALALAH. THE JTWC FORECAST IS CONSISTENT WITH THE ECMWF AND GFS SOLUTIONS AND LIES WEST OF THE CONSENSUS MEAN THROUGH THE ENTIRE FORECAST PERIOD, WITH MEDIUM CONFIDENCE. INTENSITY GUIDANCE REMAINS MIXED AND HAS BACKED OFF SIGNIFICANTLY SINCE THE PREVIOUS RUN. THE HWRF, COAMPS-TC (NAVGEM) AND MESOSCALE GFS ALL SHOW WEAKENING FROM TAU 00, WHILE THE SHIP AND RIPA, RICN AND DTOP RI AIDS ALL SHOW VARIOUS DEGREES OF INTENSIFICATION. THE MESOSCALE MODELS BEING SO LOW ARE BRINGING THE CONSENSUS DOWN TO BASICALLY STEADY STATE THROUGH THE FORECAST PERIOD. THE JTWC FORECAST LIES JUST SLIGHTLY BELOW THE RIPA GUIDANCE, AND PEAKS ABOUT 15 KNOTS HIGHER THAN THE CONSENSUS MEAN, THEN REMAINS ABOUT 10 KNOTS HIGHER THAN THE MEAN THROUGH THE WEAKENING PHASE. DUE TO THE SIGNIFICANT DISAGREEMENT BETWEEN THE VARIOUS INTENSITY CONSENSUS MEMBERS, THERE IS LOW CONFIDENCE IN THE JTWC INTENSITY FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN