Typhoon 28W(RAI) to pass over Palawan within 12hours,2nd intensity peak forecast in 36hours//TD 29W short-lived Northwest of Singapore,17/03utc

JTWC IS ISSUING 6HOURLY WARNINGS ON 28W(RAI). WARNING 2/FINAL WAS ISSUED AT 17/03UTC ON 29W. 3HOURLY SATELLITE BULLETINS ARE ISSUED ON BOTH SYSTEMS.

17/0510UTC.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TY 28W CONTINUES TO TRACK WESTWARD ALONG THE SOUTHERN SIDE OF A DEEP STR TO THE NORTH. THE SYSTEM IS FORECAST TO PASS OVER PALAWAN ISLAND WITHIN THE NEXT 12 HOURS, THEN GRADUALLY TURN NORTHWESTWARD IN A GRACEFUL ARC THROUGH 48H, WHERE IT WILL LIE JUST EAST OF CENTRAL VIETNAM. AS THE STEERING RIDGE RETREATS EASTWARD AFTER 48H, THE SYSTEM WILL TURN SHARPLY NORTH, THEN NORTHEAST THROUGH 96H. AS THE SYSTEM WEAKENS IT WILL COME UNDER THE STEERING INFLUENCE OF THE LOW LEVEL FLOW AND TURN EAST-SOUTHEAST BY 120H. NOW THAT TY 28W HAS EMERGED BACK OVER THE WARM WATERS OF THE SULU SEA, THE IMPROVED OUTFLOW, WARM SSTS AND REDUCED VWS WILL LEAD TO A PERIOD OF INTENSIFICATION, PEAKING AT 110 KNOTS/CAT 3 AT 36H. THIS WILL BE THE HIGH WATER MARK, AS AFTER THE SYSTEM TURNS POLEWARD, DRAMATICALLY INCREASED SHEAR, DECREASED SSTS, AND DRY AIR ENTRAINMENT WILL CONSPIRE TO DECAPITATE AND SMOTHER THE SYSTEM AND ULTIMATELY LEAD TO ITS DEMISE NO LATER THAN 120H.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN AREA OF FLARING DEEP CONVECTION EMBEDDED WITHIN A SLIGHTLY ELONGATED AND DISORGANIZED AREA OF HIGH-LEVEL CIRRUS BLOWOFF. THE MOST RECENT MICROWAVE IMAGERY AVAILABLE WAS FROM 162048Z AND DEPICTED A SMALL MICROWAVE EYE FEATURE, PARTICULARLY IN THE COLOR COMPOSITE 89GHZ IMAGE. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON BOTH THE CLOSE GROUPING OF AGENCY FIXES AND EXTRAPOLATION OF THE MICROWAVE EYE FEATURE. THE INITIAL INTENSITY IS ASSESSED AT A GENEROUS 100 KNOTS/CAT 3, RIGHT AT THE AVERAGE OF AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T5.5 AND THE ADT VALUE OF T5.3. THE SYSTEM HAS TAKEN A SLIGHTLY MORE WESTWARD COURSE AFTER MOVING INTO THE SULU SEA, BUT OVERALL REMAINS TRACKING WEST ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE NORTH. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE FOR DEVELOPMENT, WITH LOW TO MODERATE VERTICAL WIND SHEAR, GOOD WESTWARD AND POLEWARD OUTFLOW AND WARM SSTS.

MODEL DISCUSSION: TRACK GUIDANCE REMAINS IN GOOD AGREEMENT THROUGH 48H, THEN NOT SURPRISINGLY BEGINS TO DIVERAGE DURING THE RECURVE. WHILE THE MODELS DO SPREAD AFTER 48H, OVERALL THE UNCERTAINTY IS FAIRLY MODEST, WITH ALL MODELS, WITH THE EXCEPTION OF GALWEM, CONSTRAINED WITHIN A 185KM ENVELOPE, EVEN AT 120H. OVERALL CONFIDENCE IS HIGH THROUGH 48H, BUT DECREASES TO MEDIUM THEREAFTER IN LIGHT OF THE CLIMATOLOGICAL UNCERTAINTY SURROUNDING RECURVE EVENTS, ESPECIALLY WHEN COMBINED WITH RAPID DISSIPATION. THE INTENSITY GUIDANCE IS IN GOOD AGREEMENT THAT THE SYSTEM WILL INTENSITY SLIGHTLY AS IT MOVES INTO THE SOUTH CHINA SEA, THEN RAPIDLY WEAKEN AFTER THE ONSET OF THE HIGH SHEAR AFTER TAU 48. THE JTWC FORECAST LIES ALONG THE HIGH END OF THE GUIDANCE PACKAGE, WITH MEDIUM CONFIDENCE.

TROPICAL DEPRESSION 29W (TWENTYNINE), LOCATED APPROXIMATELY 350 KM NORTH-NORTHWEST OF SINGAPORE, HAS TRACKED WESTWARD AT 19 KM/H OVER THE PAST SIX HOURS. ANIMATED VISIBLE IMAGERY, RADAR DATA FROM THE MALAYSIA RADAR NETWORK AND SURFACE OBSERVATIONS FROM KUANTAN, MALAYSIS, INDICATE THAT TD 28W MADE LANDFALL JUST NORTH OF KUANAN NEAR THE 162300Z HOUR AND HAS CONTINUED TO MOVE INLAND. THE ADVANCED DVORAK TECHNIQUE (ADT) AND SATCON ESTIMATES PRIOR TO LANDFALL WERE AS HIGH AS T2.5, INDICATING THAT THE SYSTEM LIKELY BRIEFLY REACHED AT LEAST 30 KNOTS PRIOR TO LANDFALL. HOWEVER NOW THAT THE SYSTEM IS OVER LAND, IT IS ALREADY STARTING TO WEAKEN AND WILL DISSIPATE AS A TROPICAL CYCLONE OVER LAND WITHIN THE NEXT 12 TO 24 PRIOR TO REACHING THE WEST COAST OF MALAYSIA. IT IS LIKELY THAT A WEAK, REMNANT CIRCULATION WILL MOVE OFF THE WEST COAST, BUT IT IS NOT EXPECTED TO REDEVELOP AT THIS TIME. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 170000Z IS 12 FEET.

AN AREA OF CONVECTION (INVEST 94B) HAS PERSISTED NEAR 4.4N 87.4E, APPROXIMATELY 875 KM EAST-SOUTHEAST OF COLOMBO, SRI LANKA. ANIMATED ENHANCED INFRARED IMAGERY AND A 152232Z SSMIS 91GHZ IMAGE DEPICT FLARING CONVECTION IN THE NORTH-NORTHEASTERN PERIPHERY WRAPPING INTO THE LOW LEVEL CIRCULATION (LLC). ENVIRONMENTAL ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH FAIR POLEWARD OUTFLOW AND WARM (28-29C) SEA SURFACE TEMPERATURES OFFSET BY MODERATE (15- 20KT) VERTICAL WIND SHEAR. GLOBAL MODELS ARE IN AGREEMENT THAT INVEST 94B WILL INTENSIFY AND TRACK EASTWARD TOWARD MYANMAR WITHIN THE NEXT 48-72HRS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1009 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO LOW.