WDPS31 PGTW 281500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 15P (JUDY) WARNING NR 007// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 15.5S 168.3E INITIAL INTENSITY: 75 KTS GEOGRAPHIC REFERENCE: 132 NM NORTH OF PORT VILA, VANUATU MOVEMENT PAST 6 HOURS: SOUTHWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 25 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A MASS OF BLOOMING CONVECTION WITH THICK CONVECTIVE BANDS WRAPPING INTO AN ASSESSED LOW LEVEL CIRCULATION CENTER (LLCC). UNFORTUNATELY, NO USEFUL MICROWAVE IMAGERY CAME IN FOR ANY FURTHER ANALYSIS DURING THIS FORECAST CYCLE. HOWEVER, BASED OFF THE OLDER 280457Z SSMIS 91GHZ IMAGE, THERE WAS AN INDICATION OF A MICROWAVE EYE. ENVIRONMENTAL ANALYSIS INDICATES TC JUDY TO BE IN FAVORABLE CONDITIONS FOR CONTINUAL TROPICAL DEVELOPMENT. THESE CONDITIONS ARE CHARACTERIZED BY CONSISTENT POLEWARD OUTFLOW ALOFT, LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS), A STRONG 850 MB VORTICITY SIGNATURE, AND VERY WARM (29-30 C) SEA SURFACE TEMPERATURES (SST). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED MSI AND THE PGTW FIX LOCATION. THE INITIAL INTENSITY OF 75 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A BLEND OF MULTI-AGENCY AND AUTOMATED DVORAK ESTIMATES. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE EAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.0 - 65 KTS KNES: T4.5 - 77 KTS PHFO: T4.5 - 77 KTS NFFN: T4.5 - 77 KTS CIMSS SATCON: 77 KTS AT 281032Z CIMSS ADT: 72 KTS AT 281300Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 5-10 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC JUDY CONTINUES ITS SOUTHWARD TRACK AS IT CROSSES THE STR AXIS TO THE EAST. AFTER TAU 12, THE SYSTEM WILL SHIFT SOUTH-SOUTHEASTWARD AND INCREASE IN INTENSITY TO 80 KNOTS. TC JUDY WILL THEN INCREASE IN INTENSITY AGAIN TO 85 KNOTS AS IT MAKES A FURTHER SHIFT SOUTHEASTWARD BY TAU 24. BY TAU 48, TC 15P WILL PICK-UP TRACK SPEED AND DECREASE IN INTENSITY TO 75 KNOTS AS IT WILL BEGIN TO ENTER A MORE HOSTILE ENVIRONMENT CHARACTERIZED BY STRONGER VWS AND CONTINUOUS DRY AIR FROM THE WEST BEING WRAPPED INTO THE SYSTEM. BY TAU 72, TC JUDY WILL CROSS OVER RELATIVELY COOLER (25-26 C) SSTS AND BEGIN TO MAKE ITS TRANSITION TO A SUBTROPICAL SYSTEM. BY TAU 96, TC 15P WILL BECOME FULLY SUBTROPICAL. MODEL DISCUSSION: THE JTWC TRACK CONSENSUS MEMBERS ARE IN RELATIVELY GOOD AGREEMENT WITH A CONTINUAL SOUTHWARD TRACK, FOLLOWED BY A SOUTHEASTWARD TRACK IN THE EARLIER TAUS. THE NAVGEM TRACKER IS THE OUTLIER WITH A MORE SOUTHWARD TRACK AFTER TAU 24 THAN THE OTHER MEMBERS. BECAUSE OF THIS, THE JTWC FORECAST TRACK IS PLACED SLIGHTLY TO THE LEFT OF CONSENSUS AFTER TAU 24. THE FORECAST MODEL ENVELOPE HAS A 65 NM SPREAD BY TAU 24 WHICH PROGRESSIVELY INCREASES TO 144 NM BY TAU 72. AS A RESULT, THE JTWC FORECAST TRACK TO SET WITH MEDIUM CONFIDENCE. THE JTWC INTENSITY CONSENSUS MEMBERS ARE ALSO IN GOOD AGREEMENT SHOWING AN INCREASE IN INTENSITY AT TAUS 24, THEN A GRADUAL DECREASE THROUGHOUT THE FORECAST PERIOD. THE COAMPS-TC INTENSITY GUIDANCE SHOWS A LOW PROBABILITY OF RAPID INTENSIFICATION BETWEEN TAU 6 AND TAU 30. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN