South Pacific: 23P(NIRAN) US/Cat 4,still intensifying likely above the forecast/South Indian: 24S(HABANA): explosive intensification,05/09utc updates

23P(NIRAN). 05/09UTC. ENHANCED INFRA-RED ANIMATION SHOWS COOLING CLOUD TOPS AROUND THE WELL DEFINED EYE .THE SATELLITE SIGNATURE IS NOW IMPRESSIVE FOR THIS COMPACT SYSTEM. THE CYCLONE IS STILL INTENSIFYING. DVORAK ANALYSIS FROM PGTW(JTWC) IS AT 7.0/7.0 AT 05/0850UTC. IF NEEDED CLICK TO ANIMATE.

23P(NIRAN). WARNING 18 ISSUED AT 05/09UTC. TC 23P IS RAPIDLY MOVING SOUTHEASTWARD ALONG THE SOUTHWESTERN PERIPHERY OF A COMBINED NEAR EQUATORIAL AND SUBTROPICAL RIDGE COMPLEX CENTERED TO THE NORTHEAST. THE ENVIRONMENT REMAINS FAVORABLE FOR THE MOMENT WITH MODERATE (20-25 KT) VERTICAL WIND SHEAR BEING OFFSET BY VERY STRONG POLEWARD OUTFLOW AND WARM (29C) SSTS. THE SYSTEM IS FORECAST TO CONTINUE TRACKING SOUTHEASTWARD THROUGH 48H ALONG THE TIGHT GRADIENT BETWEEN THE RIDGE COMPLEX TO THE NORTHEAST AND AN APPROACHING MAJOR SHORTWAVE TROUGH TO THE WEST. BY THE END OF THE FORECAST, THE SYSTEM WILL MOVE SLIGHTLY MORE EASTWARD AS IT COMES UNDER THE STEERING INFLUENCE OF A DYNAMIC LOW TO MID-LEVEL ANTICYCLONE TO THE SOUTH. IN THE NEAR-TERM, GOOD ENVIRONMENTAL CONDITIONS WILL SUPPORT ADDITIONAL INTENSIFICATION TO A PEAK OF 120 KNOTS/US CATEGORY 4 BY12H. THEREAFTER, ENVIRONMENTAL CONDITIONS BEGIN TO RAPIDLY DETERIORATE AS THE VERTICAL WIND SHEAR INCREASES TO AN EXTENT THAT THE OUTFLOW CANNOT OVERCOME AND THE CORE BECOMES DISRUPTED. AFTER 48H, VERTICAL WIND SHEAR WEAKENS SLIGHTLY, BUT DRY AIR ENTRAINMENT AND COOL SSTS AT OR BELOW 26C WILL SERVE TO FURTHER WEAKEN THE SYSTEM AS IT BEGINS SUBTROPICAL TRANSITION. THE TRANSITION TO A STORM FORCE SUBTROPICAL SYSTEM WILL BE COMPLETE NO LATER THAN, AND POSSIBLY EARLIER THAN, 72H.

23P(NIRAN). NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH 24H BUT CROSS AND ALONG-TRACK UNCERTAINTY INCREASES SIGNIFICANTLY THEREAFTER. THE JTWC FORECAST LIES NEAR THE CONSENSUS MEAN THROUGH 24H, THEN NEAR THE ECMWF TRACK THROUGH THE REMAINDER OF THE FORECAST PERIOD. OVERALL THERE IS HIGH CONFIDENCE IN THE FIRST 24 HOURS OF THE FORECAST, AND LOW CONFIDENCE THEREAFTER.

23P(NIRAN). 05/0614UTC. THE INITIAL INTENSITY IS ASSESSED AT 115 KNOTS/US CATEGORY 4, HEDGED SLIGHTLY LOWER THAN A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T6.5 (127 KTS) AND CLOSELY ALIGNED TO A 114 KNOT WIND SPEED MEASUREMENT FROM A 050227Z AMSR2 PASS.

23P(NIRAN). 05/0630UTC.ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THE EMERGENCE OF A VERY WELL DEFINED 22KM EYE BY 0600UTC.

23P(NIRAN). 05/0630UTC.MICROWAVE IMAGE SHOWED THAT THE DEEP CONVECTION DOES NOT EXTEND ALL THE WAY AROUND THE SYSTEM, WITH A DISTINCT BREAK IN THE EYEWALL ON THE SOUTHEASTERN SIDE, INDICATIVE OF INCREASING EASTERLY WIND SHEAR. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON BOTH THE SSMIS MICROWAVE IMAGE AND THE 19KM EYE IN THE INFRARED IMAGERY.

23P(NIRAN). ROBUST POLEWARD DIVERGENCE HAS CONTRIBUTED TO THE INTENSITY SPIKE.

24S(HABANA). WARNING 3 ISSUED AT 05/09UTC. DUE TO THE EXTREMELY RAPID INTENSIFICATION (ERI),THE ENVIRONMENT IS OBVIOUSLY VERY FAVORABLE WITH VERY LOW (5-7 KTS) WIND SHEAR, STRONG POLEWARD AND MODERATE EQUATORWARD OUTFLOW AND WARM (29-30C) SSTS. TC 24S IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF A STRONG NEAR EQUATORIAL RIDGE (NER) ENTRENCHED TO THE NORTH. THE SYSTEM IS EXPECTED TO CONTINUE TRACKING EAST-NORTHEAST THROUGH 24H BUT TURN EAST AS THE NER FLATTENS OUT BY 24H. THROUGH 72H A STR BUILDS EQUATORWARD TO THE EAST, FORCING A TURN TO THE SOUTH. THEREAFTER A STRONG STR WILL BUILD IN TO THE SOUTH AND TURN TC 24S ONTO A WESTWARD TRACK THROUGH THE REMAINDER OF THE FORECAST. WHILE THERE IS HIGH UNCERTAINTY IN THE INTENSITY FORECAST DUE TO THE UNEXPECTED ERI, THE RAPID INTENSIFICATION GUIDANCE IS STILL BEING TRIPPED AND THE PRESENCE OF THE CYAN RING IN THE 37GHZ MICROWAVE IMAGERY IS INDICATIVE OF POSSIBLE ADDITIONAL DEVELOPMENT. THE FORECAST CALLS FOR THE SYSTEM TO REACH A PEAK OF 100 KNOTS/US CATEGORY 3 BY 12H BEFORE STARTING A SLOW WEAKENING TREND THROUGH THE REMAINDER OF THE FORECAST, PRIMARILY IN RESPONSE TO A DECREASE IN UPPER-LEVEL OUTFLOW AND SOME MID-LEVEL DRY AIR ENTRAINMENT.

24S(HABANA). NUMERICAL MODEL GUIDANCE IS IN POOR AGREEMENT BUT OVERALL AGREES ON THE OVERALL SCENARIO. SPREAD INCREASES TO 280KM AT 48H, INCREASING TO 410KM AT 120H. THE JTWC FORECAST LIES NEAR THE CONSENSUS MEAN WITH LOW CONFIDENCE.

24S(HABANA). 05/0815UTC.ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THAT TC 24S HAS UNDERGONE A CYCLE OF EXTREMELY RAPID INTENSIFICATION (ERI) OVER THE PREVIOUS SIX HOURS. A SMALL 19KM WIDE EYE FEATURE DEVELOPED JUST PRIOR TO 0600UTC WITH DEEP CONVECTION COMPLETELY SURROUNDING THE VERY SMALL AND INTENSE CORE.

24S(HABANA). 05/0815UTC.

24S(HABANA). 05/0630UTC. A 050630Z GMI 89GHZ MICROWAVE IMAGE CONFIRMED THE VERY WELL DEFINED EYE SURROUNDED BY DEEP CONVECTION. THE 37GHZ IMAGE CONFIRMED THE PRESENCE OF THE STRONG CYAN RING SIGNATURE, INDICATIVE OF THE RECENT RAPID INTENSIFICATION AND HINTING AT THE POTENTIAL FOR SOME ADDITIONAL DEVELOPMENT IN THE NEAR TERM.

24S(HABANA). THE CYCLONE IS TRACKING OVER A POOL OF WATER WITH HIGH OCEAN HEAT CONTENT.