TS 24W(KOMPASU) peaking near Typhoon intensity by 12hours/23W(NAMTHEUN) battling wind shear//TS 16E(PAMELA) set to reach CAT 2 within 36h,12/04utc

AN AREA OF CONVECTION (INVEST 96W) IS LOCATED NEAR 10.8N 146.7E, APPROXIMATELY 370 KM SE OF GUAM. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A BROAD, DISORGANIZED LOW-LEVEL CIRCULATION (LLC) WITH FLARING CONVECTION IN THE SOUTHWESTERN QUADRANT. A 111809Z SSMIS 91GHZ MICROWAVE IMAGE INDICATES SHALLOW BANDING OVER THE EASTERN SEMICIRCLE WITH A WEAKLY DEFINED CENTER. A 120004Z ASCAT-C IMAGE REVEALS 10-15 KNOT SOUTHERLY WINDS OVER THE EASTERN SEMICIRCLE. UPPER-LEVEL ANALYSIS INDICATES THE DISTURBANCE IS LOCATED UNDER SOUTHERLY FLOW ALONG THE EASTERN PERIPHERY OF AN UPPER-LEVEL LOW WITH MODERATE TO STRONG (20 TO 25 KNOTS) VERTICAL WIND SHEAR. GLOBAL MODELS INDICATE NO SIGNIFICANT DEVELOPMENT AS THE SYSTEM DRIFTS NORTHWESTWARD OVER THE NEXT TWO DAYS WITH PERSISTENT MARGINAL CONDITIONS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TROPICAL STORM KOMPASU IS FORECAST TO CONTINUE TRACKING NEARLY DUE WEST THROUGH THE FORECAST PERIOD, ALONG THE SOUTHERN PERIPHERY OF THE DEEP SUBTROPICAL RIDGE(STR) LYING OVER CENTRAL CHINA. THE SYSTEM IS EXPECTED TO MAKE ITS FIRST LANDFALL ALONG THE COAST OF CENTRAL HAINAN ISLAND NEAR 36H, EMERGE INTO THE GULF OF TONKIN BY 48H, THEN MAKE A SECOND LANDFALL ALONG THE COAST OF NORTH VIETNAM NEAR 72H. THE GENERAL ENVIRONMENT IS EXPECTED TO REMAIN MARGINALLY FAVORABLE FOR ANOTHER 12 TO 18 HOURS, WITH SHEAR VALUES REMAINING AT OR BELOW CURRENT LEVELS. IN RESPONSE, TS 24W IS FORECAST TO INTENSIFY TO 60 KNOTS BY 12H. AFTER 12H, THE SYSTEM WILL WEAKEN STEADILY UNDER INCREASING VWS. AFTER CROSSING HAINAN, THE SYSTEM IS EXPECTED TO EMERGE INTO THE GULF OF TONKIN AS A WEAK TROPICAL STORM, AND THE COMBINATION OF WEAK OUTFLOW AND MODERATE LEVELS OF VWS WILL PRECLUDE ADDITIONAL INTENSIFICATION BEFORE THE SECOND LANDFALL. ONCE ASHORE, FRICTIONAL EFFECTS WITH THE RUGGED TERRAIN OF VIETNAM WILL RAPIDLY ERODE THE CIRCULATION, LEADING TO DISSIPATION OVER NORTHERN LAOS NO LATER THAN 120H.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE BROAD EXTENT OF TS 24W, WITH SPIRAL BANDS EXTENDING FROM THE TAIWAN STRAIT IN THE NORTH TO SOUTHERN LUZON IN THE SOUTH. WHILE THE SYSTEM IS OVERALL QUITE LARGE, THE INNER CORE IS RELATIVELY SMALL. HAVING MOVED OFF TO THE WEST OF LUZON, THE EASTERN SIDE OF THE CIRCULATION HAS STRENGTHENED AND THE CORE HAS BECOME MORE SYMMETRICAL. HOWEVER, THE MSI AND ENHANCED INFRARED IMAGERY SHOW THAT CORE CONVECTION HAS DECREASED SIGNIFICANTLY OVER THE PAST SIX HOURS. A 112308Z SSMIS 91GHZ MICROWAVE IMAGE SHOWED A WELL-DEFINED BAND OF HEAVY CONVECTION TO THE SOUTHWEST OF LUZON, WEAK SPIRAL BANDS WITHIN THE CORE, BUT LITTLE TO NO DEEP CONVECTION IN THE NORTHEAST QUADRANT OF THE SYSTEM. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A SPIRAL BAND ANALYSIS OF THE AFOREMENTIONED MICROWAVE IMAGE. THE INITIAL INTENSITY OF 55 KNOTS IS ALSO ASSESSED WITH HIGH CONFIDENCE BASED ON AN AGREEMENT ACROSS ALL OBJECTIVE AND SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES. THE ENVIRONMENT IS OVERALL MARGINALLY FAVORABLE, WITH WARM SSTS AND STRONG EQUATORWARD AND MODERATE POLEWARD OUTFLOW BEING OFFSET BY MODERATE EASTERLY VERTICAL WIND SHEAR.

MODEL DISCUSSION: TRACK GUIDANCE IS IN VERY GOOD AGREEMENT WITH MINIMAL SPREAD OF 140KM AT FIRST LANDFALL, INCREASING TO A MODEST 175KM AT SECOND LANDFALL. THE JTWC TRACK REMAINS CONSISTENT WITH THE PREVIOUS FORECAST AND JUST SLIGHTLY NORTH OF THE CONSENSUS MEAN, WITH HIGH CONFIDENCE. LIKEWISE, INTENSITY GUIDANCE IS IN GOOD AGREEMENT AND THE JTWC FORECAST LIES CLOSE TO THE CONSENSUS MEAN, THOUGH SLIGHTLY LOWER THAN THE CONSENSUS MEAN, ESPECIALLY AFTER THE FIRST LANDFALL, WITH MEDIUM CONFIDENCE.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 23W APPEARS TO HAVE ITS BATTLE WITH THE PERSISTENT WIND SHEAR, AT LEAST FOR THE TIME BEING, WITH THE COMPACT LLCC NOW FULLY EXPOSED IN THE MOST RECENT ANIMATED VISIBLE IMAGERY. THE SYSTEM IS MOVING NEARLY DUE WEST JUST SOUTH OF THE 20TH LATITUDE, ALONG THE SOUTHERN PERIPHERY OF THE DEEP SUBTROPICAL RIDGE(STR) TO THE NORTH. THIS GENERAL MOTION IS EXPECTED TO CONTINUE, WITH A TURN MORE NORTH OF WEST EXPECTED IN THE NEXT FEW HOURS, THROUGH 36H. THEREAFTER, THE RIDGE TO THE NORTH WEAKENS WHILE THE RIDGE TO THE SOUTHEAST BUILDS AND MOVES WEST, UNDERCUTTING THE SYSTEM TO THE SOUTH. IN RESPONSE, TS 23W WILL SLOW AND GRADUALLY TURN POLEWARD BETWEEN 48/72H, AND COULD BECOME QUASI-STATIONARY DURING THIS PERIOD. BY 72H THE RIDGE TO THE SOUTH REORIENTS TO A SOUTHWEST-NORTHEAST AXIS, AND TS 23W WILL KICK OUT TO THE NORTHEAST ALONG THE NORTHWESTERN PERIPHERY OF THE RIDGE. WHILE OUTFLOW AND SSTS REMAIN FAVORABLE FACTORS FOR DEVELOPMENT, THE PERSISTENT SHEAR IS EXPECTED TO REMAIN IN PLACE, WITH A VERY SLIGHT WEAKENING OF THE SHEAR VALUES EXPECTED THROUGH 24H, THUS THE VARIOUS ENVIRONMENTAL PARAMETERS WILL OFFSET ONE ANOTHER. IN RESPONSE, TS 23W IS FORECAST TO MAINTAIN INTENSITY THROUGH 24H, BEFORE BEGINNING A GRADUAL WEAKENING PROCESS THROUGH THE REMAINDER OF THE FORECAST AS SHEAR ONCE AGAIN OVERCOMES THE WARM SSTS AND GOOD OUTFLOW ALOFT.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A COMPACT, WELL-DEFINED, FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH FLARING DEEP CONVECTION SHEARED TO THE NORTH AND NORTHEAST OF THE LLCC. WHILE THE LLCC HAD BEEN TUCKED UNDER THE CONVECTION EARLIER IN THE DAY, IT HAS BEEN UNABLE TO OVERCOME THE PERSISTENT SOUTHERLY SHEAR. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC, AMONGST THE TIGHT GROUPING OF AGENCY FIXES. THE INITIAL INTENSITY OF 45 KNOTS IS ASSESSED WITH MEDIUM CONFIDENCE, ON THE HIGHER END OF THE AGENCY INTENSITY ESTIMATES, IN LINE WITH THE ADT ESTIMATE. A 112330Z ASCAT-B BULLSEYE PASS INDICATED A MODEST AREA OF 40-45 KNOT WINDS CONFINED TO THE NORTHEAST QUADRANT. AS DISCUSSED, THE SYSTEM CONTINUES TO STRUGGLE AGAINST MODERATE TO STRONG SOUTHERLY WIND SHEAR, FLOWING NORTHWARD IN A TIGHT GRADIENT BETWEEN AN UPPER-LEVEL ANTICYCLONE TO THE EAST AND A NORTH-SOUTH ORIENTED TUTT-CELL OVER THE MARIANAS. OUTSIDE OF THE SHEAR, THE ENVIRONMENT IS OTHERWISE FAVORABLE WITH WARM SSTS AND ROBUST POLEWARD OUTFLOW, WHICH TURNS EAST SOUTH OF THE 30N LATITUDE.

MODEL DISCUSSION: TRACK GUIDANCE IS IN POOR AGREEMENT. THE GFS AND HWRF TURN THE SYSTEM NORTHWARD AFTER 00H, SLOWLY DRIFTING THE SYSTEM INTO THE RIDGE TO THE NORTH. THESE SOLUTIONS ARE CONSIDERED UNLIKELY AS THE SYSTEM IS NOT STRONG ENOUGH TO PUNCH INTO THE RIDGE TO THE NORTH. THE REMAINDER OF THE GUIDANCE AGREES ON A GENERAL WEST-NORTHWEST TRACK, TURNING GRADUALLY NORTHEASTWARD BUT DISAGREES ON THE SPEED OF THE SYSTEM, AND THE TIMING AND SHARPNESS OF THE TURN. THE ECMWF AND JGSM REPRESENT THE WIDE OUTLIERS, WHILE NAVGEM TAKES IN THE INSIDE TRACK. THE JTWC FORECAST HUGS THE SOUTHERN OR LEFTWARD EDGE OF THE GUIDANCE ENVELOPE THROUGH THE MAJORITY OF THE FORECAST. IN LIGHT OF THE WIDE SPREAD AND DIVERGENT MODEL SOLUTIONS, THERE IS LOW CONFIDENCE IN THE JTWC FORECAST TRACK. INTENSITY GUIDANCE IS ALSO MIXED WITH HWRF AND COAMPS-TC SHOWING NEAR TERM INTENSIFICATION TO A PEAK OF 60 KNOTS, WHILE THE REMAINDER OF THE GUIDANCE INDICATING STEADY WEAKENING. IN LIGHT OF THE RECENT IMPACT OF HIGHER THAN EXPECTED SHEAR AND THE UNLIKELIHOOD OF THE SYSTEM RECOVERING FROM THE SHEAR, THE JTWC FORECAST REMAINS CLOSE TO THE MEAN OF THE GUIDANCE SUGGESTING WEAKENING, WITH LOW CONFIDENCE.

CURRENT INTENSITY IS 60KNOTS AND IS FORECAST TO PEAK AT 95KNOTS/CAT 2 BY 13/12UTC CLOSE TO THE MEXICAN COASTLINE.

TS 16E(PAMELA). TRACK AND INTENSITY GUIDANCE.

12/0345UTC.