TC 15P(JUDY) rapid intensification past 24h now CAT 2 US tracking almost over PORT VILA and forecast to peak at 110knots by 48h//2821utc

JTWC IS ISSUING 6HOURLY WARNINGS ON TC 15P(JUDY). 3HOURLY WARNINGS ARE ISSUED ON 15P, ON THE REMNANTS OF TC 14S(ENALA) AND ON THE OVER-LAND REMNANTS OF TC 11S(FREDDY).

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL CYCLONE 15P (JUDY) HAS RAPIDLY INTENSIFIED OVER THE PAST 24 HOURS, WITH INTENSITIES INCREASING FROM 50 KNOTS TO AT LEAST 85 KNOTS SINCE 1800Z YESTERDAY. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY INDICATES THIS TREND IS CONTINUING, WITH A RAGGED EYE TRYING TO ESTABLISH ITSELF OVER THE PAST COUPLE OF HOURS AS THE SYSTEM MOVED OVER THE ISLANDS OF EPI AND EMAE. IN THE EIR, A RAGGED EYE IS BEGINNING TO OPEN UP, BUT CLOUD TEMPERATURES IN THIS EYE-LIKE FEATURE REMAIN VERY COLD, WHILE CLOUD TOP TEMPERATURES IN THE SURROUNDING CONVECTIVE BANDS ARE AN EXTREMELY COLD -96C. WHILE THE EYE REMAINS RAGGED IN THE EIR, IN THE 281726Z GMI MICROWAVE IMAGERY THE EYE IS VERY WELL-DEFINED THROUGH THE COLUMN AND PROVIDED HIGH CONFIDENCE TO THE INITIAL POSITION. HOWEVER, BASED ON ANALYSIS OF THE 37GHZ AND 89GHZ IMAGES, THE PRESENCE OF SOME MODERATE WESTERLY MID-LEVEL SHEAR IS RESULTING IN ABOUT 11NM OF EASTERLY VORTEX TILT, POSSIBLY ONE REASON WHY THE EYE HAS NOT YET BECOME FULLY ESTABLISHED. SINCE THE EYE HAS YET TO COMPLETELY CLEAR OUT IN THE EIR, DVORAK INTENSITY ESTIMATES REMAIN CONSTRAINED FOR THE MOST PART, CONTINUING TO USE THE CURVED BAND OR CDO METHODS BY AND LARGE. HENCE THERE IS A LARGE SPREAD IN THE AGENCY CURRENT INTENSITY ESTIMATES BETWEEN T4.5 (77 KTS) ON THE LOW END ALL THE WAY UP TO A VERY AGGRESSIVE T6.0 (115 KTS) FROM KNES. THE JTWC INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE AT 85 KNOTS BASED ON A BLEND OF THE SUBJECTIVE AND OBJECTIVE FIX ESTIMATES. THE SYSTEM LOOKS TO HAVE SLOWED A BIT AS IT DRAGGED ACROSS THE NORTHERN ISLANDS OF VANUATU BUT IS GENERALLY MOVING SOUTHWARD ALONG THE WEST SIDE OF THE SUBTROPICAL RIDGE (STR) TO THE EAST. THE ENVIRONMENT REMAINS FAVORABLE FOR FURTHER DEVELOPMENT, WITH LOW VWS, AND WARM SSTS. OUTFLOW HAS IMPROVED, WITH THE EQUATORWARD OUTFLOW CHANNEL NOW BEING JOINED BY A NEWLY FORMED POLEWARD CHANNEL. MODERATE MID-LEVEL IS HOWEVER PUSHING IN FROM THE WEST AND SLOWING THE PACE OF INTENSIFICATION SOMEWHAT.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC JUDY CONTINUES TO TRACK SOUTHWARD, THOUGH AS MENTIONED, RECENT SATELLITE IMAGERY SUGGESTS IT MAY BE SLOWING DOWN A BIT AS IT APPROACHES PORT VILA. THE SYSTEM IS EXPECTED TO CONTINUE SOUTHWARD AS IT ROUNDS THE AXIS OF THE STEERING RIDGE, AND EITHER PASS JUST A HAIR WEST OF EFATE ISLAND, OR MAKE LANDFALL DIRECTLY ON THE ISLAND, WITHIN THE NEXT 6 TO 12 HOURS. ONCE PAST EFATE, THE SYSTEM IS EXPECTED TO PASS SOUTH OF THE RIDGE AXIS AND TURN ONTO SOUTHEASTWARD TRAJECTORY THROUGH THE REMAINDER OF THE FORECAST PERIOD. IN TERMS OF INTENSITY, TC JUDY HAS AT MOST ANOTHER 18-24 HOURS OF FRIENDLY CONDITIONS BEFORE THINGS GET NASTY. WHILE THE MID-LEVEL SHEAR CONTINUES TO BE AN ISSUE, HIGH RESOLUTION MODELS SUGGEST THAT THE RAPID DEVELOPMENT OF INNER CORE CONVECTION SHOULD HELP PUSH BACK AGAINST THIS SHEAR OVER THE NEXT 12 HOURS. THE IMPROVEMENT IN UPPER-LEVEL POLEWARD OUTFLOW WILL ENHANCE THE REDUCED MESOSCALE SHEAR, ALLOWING THE SYSTEM TO CONTINUE TO RAPIDLY INTENSIFY THROUGH TAU 12. THE PACE OF INTENSIFICATION WILL SLOW AFTER TAU 12 AS DEEP-LAYER WESTERLY SHEAR STARTS TO INCREASE, AND SSTS START TO COOL. THE PEAK OF 110 KNOTS IS STILL EXPECTED AROUND TAU 18, HOLDING ON THROUGH TAU 24. AFTER THIS POINT HOWEVER, THINGS BEGIN TO DRASTICALLY CHANGE. SHEAR DOUBLES TO 25 KNOTS BY TAU 36, THEN DOUBLES AGAIN TO 50 KNOTS BY TAU 60, AS THE SYSTEM BECOMES EMBEDDED WITHIN THE SUBTROPICAL WESTERLIES. BY TAU 36, SSTS DROP BELOW 26C, AND THE SYSTEM BEGINS TO MERGE INTO PHASE WITH A SHARP 500MB BAROCLINIC TROUGH, MARKING THE START OF SUBTROPICAL TRANSITION (STT). THE SYSTEM SHOULD COMPLETE STT NO LATER THAN TAU 72, BUT IN REALITY, IS MORE LIKELY TO TRANSITION TO A STORM-FORCE SUBTROPICAL LOW BY TAU 60.

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE REMAINS IN VERY GOOD AGREEMENT THROUGH THE FORECAST PERIOD, WITH ALL CONSENSUS MEMBERS CONFINED TO A GRADUALLY EXPANDING ENVELOPE OF JUST 110NM BY TAU 72. THE JTWC FORECAST LIES ON THE WESTERN SIDE OF THE TRACK ENVELOPE THROUGH THE FORECAST, WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS MIXED, WITH THE COAMPS-TC (BOTH GFS AND NAVGEM) AND THE GFS GUIDANCE SUGGESTING THE SYSTEM HAS ALREADY PEAKED AND WILL WEAKEN STEADILY FROM HERE TO THE END OF THE FORECAST. THE HWRF AND DECAY-SHIPS (BOTH GFS AND NAVGEM) AGREE THAT THE SYSTEM WILL INTENSIFY SOME MORE, BUT ONLY UP TO 95-100 KNOTS. MEANWHILE, THE COAMPS-TC ENSEMBLE INDICATES A MODERATE (40 PERCENT) PROBABILITY OF RAPID INTENSIFICATION IN THE NEXT 6 TO 12 HOURS AND THE RIPA AND RI25-RI35 RAPID INTENSIFICATION (RI) AIDS CONTINUE TO FIRE. THE JTWC FORECAST ANTICIPATES EMERGENCE OF A WARM EYE FEATURE, AND THUS BITES ON THE RI GUIDANCE, TAKINGTHE INTENSITY UP ALONG THE RIPA TREND BUT PEAKING ABOUT 20 KNOTSLOWER THAN THE RIPA PEAK INTENSITY. CONFIDENCE IS LOW DUE TOUNCERTAINTIES IN THE IMPACT OF THE MID-LEVEL SHEAR, AND WHETHER ORNOT THE EYE CAN ACTUAL CLEAR OUT QUICKLY.