TC 22S(HALIMA): under-going Rapid Intensification up to 115KTS/CAT 4 US, possibly higher//21S(CHARLOTTE): subtropical,25/03utc

JTWC IS ISSUING 12HOURLY WARNINGS ON TC 22S(HALIMA).3HOURLY SATELLITE BULLETINS ARE ISSUED FOR TC 22S AND THE REMNANTS OF TC 21S(CHARMOTTE).

25/0150UTC.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: OVER THE PAST TWELVE HOURS TC 22S HAS SLOWED SIGNIFICANTLY, WITH THE MOTION VECTOR AROUND THREE TO FOUR KNOTS TOWARDS THE WEST AT ANALYSIS TIME UNDER COMPETING STEERING INFLUENCES BETWEEN THE SUBTROPICAL RIDGE (STR) TO THE WEST AND A NEAR EQUATORIAL RIDGE (NER) COMPLEX TO THE EAST. THE STR TO THE WEST IS FORECAST TO ERODE AND MOVE FURTHER TO THE WEST IN THE NEAR-TERM, WITH A MERIDIONAL NER-STR COMPLEX TO THE EAST ASSUMING THE DOMINANT STEERING ROLE. TC 22S IS FORECAST TO TURN POLEWARD BY 12H, AND BEGIN TO ACCELERATE AS IT MOVES ALONG AN INCREASINGLY TIGHT GRADIENT BETWEEN THE STEERING RIDGE AND A NORTH-ORIENTED UPPER-LEVEL TROUGH. BY 72H THE SYSTEM WILL TURN EASTWARD AS THE NER TO THE NORTH MOVES TO A POSITION DUE NORTH OF THE SYSTEM AND A STRONG LOW TO MID-LEVEL STR BUILDS IN TO THE SOUTHEAST AND EFFECTIVELY BLOCKS ANY FURTHER POLEWARD MOVEMENT. BY THE END OF THE FORECAST THE TRACK WILL BECOME MORE ERRATIC, POTENTIALLY LOOPING FIRST EQUATORWARD THEN POLEWARD AS IT ONCE AGAIN MOVES INTO A WEAK STEERING PATTERN. THE ENVIRONMENT IS ABOUT AS OPTIMUM FOR INTENSIFICATION AS IT COULD BE, WITH VERY LOW SHEAR, VERY WARM SSTS AND ROBUST RADIAL OUTFLOW. RECENT EIR SUGGESTS THE EYE MAY FINALLY BE ESTABLISHING ITSELF, AND THE RECENT BURST OF LIGHTNING ACTIVITY SUGGESTS THE IMMINENT ONSET OF ANOTHER ROUND OF POTENTIALLY RAPID INTENSIFICATION, TO A PEAK OF 115 KNOTS/CAT 4 US, THOUGH IT IS POSSIBLE THAT THE ULTIMATE PEAK COULD BE CLOSER TO 125 KNOTS, ESPECIALLY IF THE EYE CAN CLEAR OUT AND WARM SIGNIFICANTLY. THE OPTIMUM ENVIRONMENTAL CONDITIONS SHOULD PERSIST FOR ABOUT 24 TO 36 HOURS BEFORE INCREASING SHEAR AND DECREASING OUTFLOW ALOFT WILL CONSPIRE TO WEAKEN THE SYSTEM SIGNIFICANTLY. ENVIRONMENTAL CONDITIONS LEVEL OFF AS THE SYSTEM TRACKS EASTWARD AFTER 72H, AND WHILE NOT AS OPTIMUM, WILL SUPPORT MAINTENANCE OF A TYPHOON STRENGTH SYSTEM THROUGH THE END OF THE FORECAST.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A VERTICAL COMPACT SYSTEM, WITH THE EXTENT OF THE -80C CLOUD SHIELD LIMITED TO APPROXIMATELY 270KM. THE EWS-G IRBD ENHANCEMENT SHOWED A VERY SMALL (LESS THAN 19KM) WARM SPOT OR NASCENT EYE FEATURE EMBEDDED WITHIN THE CENTRAL DENSE OVERCAST. THE EYE FEATURE HAS BEEN PRESENT ON AND OFF FOR SEVERAL HOURS, BUT HAS YET TO BE ABLE TO PERSIST FOR MORE THAN A BRIEF PERIOD OF TIME. 250110Z EIR IMAGERY SHOWS THAT A SOLID EYE BEGINNING TO FORM, WITH -85C OR COLDER CONVECTIVE BANDS NOW COMPLETELY SURROUNDING THE EYE. INNER-CORE LIGHTNING ACTIVITY HAS ALSO INCREASED OVER THE PAST FEW HOURS. 242030Z AND 242317Z SSMIS 91GHZ IMAGERY SHOWED DEEP CONVECTIVE BANDING WRAPPING INTO A VERY CLEAR AND EXTREMELY SMALL MICROWAVE EYE FEATURE, THOUGH THE EYEWALL HAS YET TO CONSOLIDATE ON THE SOUTHEASTERN SIDE. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE MICROWAVE EYE FEATURE. THE INITIAL INTENSITY IS ASSESSED AT 90 KNOTS/CAT 2 US, ABOVE THE BULK OF THE SUBJECTIVE AND OBJECTIVE CURRENT INTENSITY ESTIMATES WITH MEDIUM CONFIDENCE. THE HIGHER INTENSITY ESTIMATE IS BASED ON THE AN EXTRAPOLATION OF A 241325Z SENTINEL-1A SYNTHETIC APERTURE RADAR (SAR) PASS WHICH SHOWED A MAXIMUM WIND OF 95 KNOTS.

MODEL DISCUSSION: TRACK GUIDANCE IS IN FAIRLY GOOD AGREEMENT, WITH A 305KM SPREAD AT 72H. THEREAFTER, THE BULK OF THE GUIDANCE CONCURS ON A EAST OR EAST-NORTHEAST TRACK BUT DEPICTS SIGNIFICANT UNCERTAINTY, WITH SPREAD INCREASING TO 460KM BY 120H, AS THE TRACKERS STRUGGLE WITH THE EVOLUTION OF THE COMPLEX STEERING PATTERN. THE JTWC FORECAST HAS SHIFTED TO THE WEST OF CONSENSUS AND THE PREVIOUS FORECAST THROUGH 72H, THEN SHIFTED NORTH OF BOTH THROUGH 120H. CONFIDENCE IS MEDIUM THROUGH 72H, AND LOW THEREAFTER. THE BULK OF THE INTENSITY GUIDANCE, WITH THE CURIOUS EXCEPTION OF HWRF, SUPPORTS ANOTHER ROUND OF RAPID INTENSIFICATION, WITH RI25, RI30 AND RIPA TRIGGERED ON THIS CYCLE, WITH A RANGE OF PEAK INTENSITIES UP TO 125 KNOTS. ADDITIONALLY, THE COAMPS-TC ENSEMBLE INDICATED A 60-70 PERCENT PROBABILITY OF RAPID INTENSIFICATION. IN THE LATER PORTION OF THE FORECAST, THE BULK OF THE GUIDANCE SUPPORTS A GENERAL WEAKENING TREND, BUT THERE IS SIGNIFICANT UNCERTAINTY IN THE LONG-RANGE INTENSITY FORECAST WITH HWRF AND COAMPS-TC INDICATING INTENSIFICATION TO 85 KNOTS AT TAU 120H, WHILE THE THE DECAY-SHIPS INDICATING JUST 40 KNOTS AT THE SAME TIME.