TS 24W(KOMPASU)making 1st landfall over Hainan/TD 23W(NAMTHEUN)not able to overcome shear//TS 16E(PAMELA) to make landfall at peak intensity,13/04utc

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TROPICAL STORM KOMPASU CONTINUES TO TRACK FAIRLY RAPIDLY WESTWARD ALONG THE SOUTHERN PERIPHERY OF A DEEP SUBTROPICAL RIDGE(STR) TO THE NORTH. SPEED MADE GOOD OVER THE PAST SIX HOURS HAS SLOWED SLIGHTLY, BUT IS STILL UP AROUND 28 KM/H OR SO. THE SYSTEM WILL MAINTAIN A WESTWARD TRACK THROUGH THE FORECAST PERIOD, AND IS EXPECTED TO MAKE LANDFALL ALONG THE EASTERN COAST OF HAINAN WITHIN THE NEXT 10 HOURS. THE QUICK TRANSLATION SPEED ACROSS HAINAN ISLAND WILL LIMIT THE IMPACT OF THE TERRAIN, AND KOMPASU WILL REEMERGE IN THE GULF OF TONKIN AS A 40 KNOT TROPICAL STORM. HOWEVER, BY THIS TIME, SHEAR WILL HAVE INCREASED ONCE AGAIN, WHICH COMBINED WITH WEAKLY CONVERGENT OUTFLOW ALOFT, WILL PRECLUDE INTENSIFICATION. THE SYSTEM WILL MAKE A SECOND LANDFALL IN NORTH VIETNAM NEAR 36H AND CONTINUE TRACKING INLAND INTO NORTHERN LAOS, WHERE IT IS FORECAST TO DISSIPATE NO LATER THAN 72H.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL STORM KOMPASU CONTINUES TO FIGHT AGAINST PERSISTENT MODERATE EASTERLY SHEAR. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS THAT THE LARGE AREA OF DEEP CONVECTION THAT WAS EARLIER BLOOMING NEAR THE CENTER HAS WEAKENED AND SHEARED OFF TO THE WEST, LEAVING BEHIND A MUCH SMALLER AREA OF WEAKER CONVECTIVE ACTIVITY NEAR OR JUST WEST OF THE ASSESSED LOW LEVEL CIRCULATION CENTER (LLCC). A 122251Z SSMIS 91GHZ MICROWAVE IMAGE CAUGHT THE BEGINNING OF THE DEVELOPMENT OF THIS AREA OF CORE CONVECTION, SHOWING A STRONG BAND OF HEAVY CONVECTIVE ACTIVITY TO THE SOUTH WRAPPING UP ALONG THE EASTERN SIDE OF THE LLCC, BUT NOT YET COMPLETELY SURROUNDING THE CORE. THE FIRST HINTS OF THE CENTER OF ROTATION ARE STARTING TO BECOME VISIBLE AT FAR RANGE OF CMA RADAR COVERAGE, AND JMA HAS BEEN CONDUCTING RADAR FIXES, WHICH COMBINED WITH THE AGENCY FIX POSITIONS, LENT HIGH CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY REMAINS ASSESSED AT 55 KTS WITH HIGH CONFIDENCE, WITH ALL AGENCIES AGREEING ON A T3.5 INTENSITY. THERE HAS BEEN NO SIGNIFICANT CHANGE IN THE ENVIRONMENT OVER THE PAST SIX HOURS, WITH PERSISTENT EASTERLY SHEAR STILL PUSHING BACK AGAINST MODERATE TO STRONG EQUATORWARD OUTFLOW AND VERY WARM SSTS.

MODEL DISCUSSION: TRACK GUIDANCE IS IN VERY GOOD AGREEMENT THROUGH THE LANDFALL IN VIETNAM, WHERE AFTER THE TRACKERS SPREAD OUT AS THEY LOSE THE WEAKENING VORTEX. THE JTWC REMAINS CONSISTENT WITH THE PREVIOUS FORECAST AND NEAR THE CONSENSUS MEAN TRACKER WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS LIKEWISE IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD, LENDING HIGH CONFIDENCE TO THE JTWC FORECAST.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: NOW THAT THE SOUTHEASTERN RIDGE HAS ASSUMED THE DOMINANT STEERING ROLE, TD 23W IS FORECAST TO CONTINUE TRACKING NORTHEASTWARD THROUGH THE FORECAST PERIOD. THE SYSTEM, HAVING WEAKENED SIGNIFICANTLY, IS NO LONGER EXPECTED TO BE ABLE TO MUSTER THE STRENGTH TO OVERCOME THE PERSISTENT SHEAR, AND IS FORECAST TO STEADILY BUT SLOWLY WEAKEN THROUGH THE FORECAST PERIOD. BRIEF PERIODS DURING WHICH CONVECTION MAY FLARE UP AND APPEAR OMINOUS CAN BE EXPECTED OVER THE NEXT 24 TO 36 HOURS, ESPECIALLY DURING DIURNAL MAXIMUM, BUT THE SYSTEM IS NOT EXPECTED TO ACTUALLY INTENSIFY AFTER THIS POINT. BY 48H THE SYSTEM WILL BE NEARLY GONE, AND WILL BE FULLY DISSIPATED NO LATER THAN 72H, IF NOT EARLIER.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: WHILE TD 23W HAS STRUGGLED MIGHTILY AGAINST STRONG AND PERSISTENT SOUTHERLY SHEAR, IT APPEARS TO HAVE LOST THE BATTLE AND BEGUN THE SLOW DECLINE TO ITS ULTIMATE DEMISE. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS A SMALL AREA OF FLARING CONVECTION SHEARED TO THE NORTHEAST OF AN ELONGATED LOW LEVEL CIRCULATION CENTER (LLCC), THE WESTERN BANDS OF WHICH ARE EVIDENT IN THE CLEAR REGION WEST OF THE CIRRUS SHIELD. A 122132Z ASCAT-A PASS SHOWED THE LLCC BEGINNING TO STRETCH OUT ALONG A SOUTHWEST-NORTHEAST AXIS, AND EXTRAPOLATION OF THIS DATA, COMBINED WITH THE PARTIALLY EXPOSED LLCC IN THE VISIBLE IMAGERY, LENT HIGH CONFIDENCE TO THE INITIAL POSITION. THE AGENCY CURRENT INTENSITY ESTIMATES RANGED FROM 2.0 TO 2.5, WHICH ALIGNS CLOSELY WITH THE ADT ESTIMATE COMING IN RIGHT AT THE AVERAGE AT 32 KNOTS. THE PREVIOUSLY MENTIONED ASCAT CONFIRMED THE 30 KNOT INITIAL INTENSITY ESTIMATE, SHOWING A PATCH OF 30 KNOT WIND BARBS CONSTRAINED TO THE NORTHEAST SECTOR, UNDER THE FLARING CONVECTION. INTERESTINGLY, CIMSS SHEAR ANALYSIS INDICATES THE OVERALL SHEAR ENVIRONMENT HAS IMPROVED, WITH THE MEAN SHEAR MAGNITUDE NOW ESTIMATED AT 19 KNOTS. HOWEVER, LIKELY THIS IS TOO LOW, BASED ON THE SATELLITE DEPICTION. THE UPPER-LEVEL OUTFLOW HAS ALSO WEAKENED, RESULTING IN AN INCREASINGLY UNFAVORABLE ENVIRONMENT.

MODEL DISCUSSION: AS THE VORTEX CONTINUES TO WEAKEN AND BECOME ELONGATED, MODEL TRACKERS ARE DIVERGING, WITH A 250KM SPREAD AT 36H INCREASING TO 280KM AT 72H. THE JTWC FORECAST LIES ON THE RIGHT EDGE OF THE GUIDANCE ENVELOPE THROUGH THE FORECAST PERIOD. CONFIDENCE IS MEDIUM HOWEVER, IN LIGHT OF THE NEAR-TERM SPREAD IN THE MODEL GUIDANCE. INTENSITY GUIDANCE IS MIXED, WITH ALL MODELS, AND HWRF AND COAMPS IN PARTICULAR, INDICATING NEAR-TERM INTENSIFICATION. THIS IS UNLIKELY IN LIGHT OF THE CONTINUING SHEAR AND OVERALL WEAKENING OF THE SYSTEM, SO THE JTWC FORECAST LIES BELOW ALL GUIDANCE THROUGH TAU THE FORECAST PERIOD, WITH MEDIUM CONFIDENCE.

CURRENT INTENSITY IS 60KNOTS AND IS FORECAST TO PEAK AT 70KNOTS/CAT 1 BY 13/12UTC WHILE THE HURRICANE IS FORECAST TO MAKE LANDFALL NORTH OF MAZATLAN/MEXICO.

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

13/04UTC.