TS 24W(KOMPASU) forecast to peak at Typhoon CAT 1 by 48h, TS 23W(NAMTHEUN) set to intensify// TS 16E(PAMELA) intensifying rapidly,11/04utc

JTWC IS ISSUING 6 HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON 23W AND 24W.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: THE SUBTROPICAL RIDGE(STR) WILL BUILD AND EXTEND FROM WESTWARD, THIS WILL CONTINUE DRIVING THE SYSTEM WESTWARD THROUGH THE LUZON STRAIT AND INTO THE SOUTH CHINA SEA (SCS). THE RIDGE OVER SOUTHEASTERN CHINA WILL ALSO INFLUENCE THE SYSTEM, FORCING THE MOVEMENT ACROSS HAINAN AND THE GULF OF TONKIN BEFORE MAKING LANDFALL IN NORTHERN VIETNAM BETWEEN 48/60H. THE ENVIRONMENT IS MORE FAVORABLE IN THE SCS AND TS 24W IS EXPECTED TO REACH A PEAK INTENSITY OF 70KNOTS/CAT 1 NEAR 48H. AFTERWARD, INCREASING VWS AND INTERACTION WITH HAINAN ISLAND WILL WEAKEN THE SYSTEM DOWN TO 60KNOTS AT 72H. AFTER LANDFALL, INTERACTION WITH THE RUGGED VIETNAMESE TERRAIN WILL RAPIDLY ERODE THE SYSTEM DOWN TO 20KNOTS AFTER IT CROSSES INTO LAOS NEAR CAMBODIA.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP CONVECTION WRAPPING ON THE WESTERN AND SOUTHERN SIDE OF AN OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC). THE SYSTEM REMAINS IN A LARGE MONSOON DEPRESSION WITH WIDE FORMATIVE RAIN BANDS EXTENDING ALL THE WAY OUT TO THE FAR EASTERN PHILIPPINE SEA. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE MSI LOOP AND A TIMELY 102300Z GMI 89GHZ IMAGE. THE INITIAL INTENSITY OF 45KNOTS IS BASED WITH MEDIUM CONFIDENCE ON MULTIPLE AGENCY FIXES FROM PGTW, RCTP, KNES DVORAK ESTIMATES AND THE OVERALL STRUCTURE OF THE SYSTEM, AND REMAINS HIGHER THAN RJTD DVORAK ESTIMATE AND THE ADVANCED DVORAK TECHNIQUE (ADT). ENVIRONMENTAL ANALYSES INDICATE MARGINALLY FAVORABLE CONDITIONS FOR DEVELOPMENT CHARACTERIZED BY VERY WARM SSTS IN THE PHILIPPINE SEA, AND MODERATE EASTERLY OUTFLOW ALOFT OFFSET BY MODERATE (15-20KT) VWS. TD 24W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE STR TO THE NORTHEAST.

MODEL DISCUSSION: NUMERICAL MODELS REMAIN IN TIGHT AGREEMENT WITH ONLY A MAXIMUM SPREAD OF 90KM FROM 12H THROUGH 48H AND GRADUALLY SPREADS TO 185KM BY 72H AFTER IT MOVES OVER HAINAN. THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST UP TO 48H. HOWEVER, ONCE THE SYSTEM MOVES OVER HAINAN AND INTERACTS WITH THE MOUNTAINOUS TERRAIN, THE SYSTEM TRACK MAY CHANGE SIGNIFICANTLY AND INDUCES LOW CONFIDENCE POST 60H. CONSEQUENTLY, THERE IS MODERATE CONFIDENCE IN THE INTENSITY FORECAST UP TO 48H AND LOW CONFIDENCE THEREAFTER.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 23W WILL CONTINUE ON A NORTHWEST TRACK TO THE NORTHWEST UP TO 48H. AFTERWARD, A SECONDARY SUBTROPICAL RIDGE(STR) TO THE EAST-SOUTHEAST WILL ASSUME STEERING AND DRIVE THE SYSTEM POLEWARD, CREST THE STR AXIS NEAR 72H, THEN RECURVE IT NORTHEASTWARD. THE FAVORABLE CONDITIONS WILL PROMOTE A STEADY INTENSIFICATION TO A PEAK OF 65KNOTS/CAT 1 BY 72H JUST AT THE RIDGE AXIS. AFTERWARD, INCREASING VWS AND COOLING SSTS WILL GRADUALLY DECAY THE SYSTEM DOWN TO 50KNOTS BY 96H. THEREAFTER, NAMTHEUN IS EXPECTED TO BEGIN EXTRATROPICAL TRANSITION BY 120H AS IT CONTINUES TRACKING TO THE NORTHEAST.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS ENHANCED AND DEEPENED CENTRAL CONVECTION WITH A PARTIALLY-EXPOSED LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION AND INTENSITY OF 45KNOTS ARE PLACED WITH HIGH CONFIDENCE BASED ON MULTIPLE AGENCY DVORAK FIXES AND A TIMELY 102331Z ASCAT-B BULLSEYE PASS. ENVIRONMENTAL ANALYSIS INDICATES MARGINALLY FAVORABLE CONDITIONS FOR DEVELOPMENT WITH MODERATE POLEWARD OUTFLOW, MODERATE TO HIGH VWS, AND WARM SSTS. TS 23W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF AN EASTERN EXTENSION OF THE MID-LAYER OF THE STR TO THE NORTHWEST.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIR AGREEMENT THROUGH 36H WITH A MODEST SPREAD OF 305 KM, HOWEVER, AFTER 36H THE MODEL GUIDANCE SPREADS QUICKLY WITH THE SHIFT IN STEERING AND WIDENS TO 815+ KM BY 72H. NAVGEM REPLACED GFS AS THE FAR RIGHT OUTLIER, BUT UKMET REMAINS THE MOST LEFT OUTLIER OF THE MODEL ENVELOPE. GIVEN THIS, THERE IS MEDIUM CONFIDENCE IN THE JTWC TRACK UP TO TAU 48H AND LOW CONFIDENCE AFTERWARD. THERE IS MEDIUM CONFIDENCE IN THE INTENSITY FORECAST UP TO 120H.

CURRENT INTENSITY IS 45KNOTS AND IS FORECAST TO INCREASE RAPIDLY AND PEAK AT 100KNOTS/CAT 3 BY 13/12UTC.

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

11/0345UTC.