93W has merged with 94W /TS 22W(LIONROCK) making final landfall/TD 23W(NAMTHEUN) intensifying, 10/06utc updates

JTWC IS ISSUING 6HOURLY WARNINGS ON 22W AND 23W. 3HOURLY SATELLITE BULLETINS ARE ISSUED ON 22W, 23W, 93W AND 94W.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 22W WILL BEGIN MOVING IN A MORE WEST-SOUTHWEST TRACK AS THE STEERING SUBTROPICAL RIDGE BUILDS AND EXTENDS WESTWARD OVER THE NEXT 12 HOURS. LIONROCK WILL CONTINUE ON THIS TRACK AND IS NO LONGER FAVORED TO INTENSIFY AS THE WATERS NEAR THE COAST HAVE COOLED SLIGHTLY DUE TO UPWELLING IN THE SHALLOWER WATERS. THE INTERACTION WITH LAND HAS ALSO INHIBITED THE GROWTH POTENTIAL AS THIS SYSTEM CONTINUES MOVING ALONG THE COAST, EXPECTING TO MAKE LANDFALL WITHIN THE NEXT 12 HOURS. DURING THIS TIME, THE SYSTEM WILL BEGIN THE DISSIPATION PROCESS AS IT MOVES OVER THE RUGGED TERRAIN OF VIETNAM AND WILL COMPLETE DISSIPATION NEAR THE LAOS BORDER BETWEEN 24H AND 36H.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN EXPANSIVE SYSTEM WITH THE MAIN CONVECTION OVER NORTHERN VIETNAM AND SOUTHWEST CHINA, SLIGHTLY OFFSET FROM THE LOW-LEVEL CIRCULATION (LLC) THAT REMAINS JUST OFFSHORE OF VIETNAM. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON AN LLC FEATURE IN A COMPOSITE RADAR LOOP FROM CMA. THE INITIAL INTENSITY OF 35KTS IS ASSESSED WITH MEDIUM CONFIDENCE FROM THE MULTIPLE AGENCY AND AUTOMATED DVORAK ESTIMATES. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH LOW (05-10KT) VWS, WEAK RADIAL OUTFLOW, AND WARM (27-29C) SSTS. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE LOW TO MID-LEVEL REFLECTION OF THE STR TO THE NORTHEAST.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GENERAL AGREEMENT WITH THE FORECAST TRACK. NAVGEM CONTINUES TO BE THE FAR LEFT OUTLIER, WHILE GFS REMAINS ON THE FAR RIGHT OF CONSENSUS. THE CROSS-TRACK ONLY GAINS TO A MAXIMUM SPREAD OF 75KM JUST BEFORE LANDFALL, LENDING TO MEDIUM CONFIDENCE IN BOTH THE TRACK AND INTENSITY FORECASTS.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: TD 23W WILL BEGIN TRACKING TO THE NORTHWEST AS THE TUTT WEAKENS THE SUBTROPCAL RIDGE SLIGHTLY ALLOWING NAMTHEUN TO MOVE QUICKLY TO THE NORTHWEST. DURING THE 24 TO 48 HOURS THE SYSTEM WILL TRACK TOWARDS THE NORTHWEST AND BEGIN TO TURN TOWARDS THE NORTH AND INTENSIFY TO 50 KNOTS BY 72H. SHORTLY AFTER IT GAINS INTENSITY THE SYSTEM WILL ENCOUNTER MODERATE ACCELERATION AND MOVE QUICKLY TO THE NORTHEAST AFTER 96H. DURING THE TRANSITION TO THE NORTHEAST THE SYSTEM WILL ALSO BEGIN ENCOUNTERING COOLER WATERS AND BEGIN DECREASING IN INTENSITY TO 40KTS BY 120H.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS EXTENSIVE FLARING CONVECTION OBSCURING A LOW LEVEL CIRCULATION CENTER JUST TO THE SOUTHEAST OF A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT). A 092055Z BULLSEYE ASCAT-A PASS SHOWS 25-30 KNOT WIND FIELD TO THE NORTHEAST OF THE MAIN LLCC. WIND BARBS AROUND A LOW LEVEL CIRCULATION WITH GREATER THAN 30 KNOT WIND BARBS ARE IN THE NORTHEASTERN PERIPHERY AND ARE ASSOCIATED WITH GRADIENT FLOW AND CONVECTION, RESPECTIVELY. INITIAL WIND ENVIRONMENTAL ANALYSIS INDICATES FAVORABLE CONDITIONS FOR DEVELOPMENT WITH ROBUST RADIAL OUTFLOW, LOW TO MODERATE (10-15KT) VERTICAL WIND SHEAR, AND WARM SEA SURFACE TEMPERATURES (29-30C). TD 23W IS TRACKING ALONG THE SOUTHEASTERN PERIPHERY OF THE MID-UPPER LEVEL SUBTROPICAL RIDGE TO THE NORTHWEST.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN OVERALL GOOD AGREEMENT WITH GRADUAL SPREADING TO 175KM BY 24H, INCREASING TO 520KM BY 72H. AFUM AND GFS ARE THE FAR RIGHT OUTLIERS, WHILE JGSM AND UKMET ARE THE MOST LEFT MARGIN OF THE MODEL ENVELOPE. THIS LENDS MEDIUM CONFIDENCE TO THE NEAR- TO MID-TERM PORTION OF THE JTWC TRACK FORECAST THAT IS LAID JUST TO THE LEFT OF AND SLIGHTLY FASTER THAN THE MODEL CONSENSUS (CONW). THERE IS LOW CONFIDENCE IN THE EXTENDED POTION OF THE FORECAST TO ACCOUNT FOR THE NOTABLE MODEL DIFFERENCES IN ALONG-TRACK ACCELERATION. INTENSITY GUIDANCE INDICATES A PEAK OF 50 KNOTS JUST NEAR THE NORTHEAST TURN BY 72 HOURS LENDING TO MEDIUM CONFIDENCE IN THE NEAR TO MID TERM. HOWEVER, AFTER 72H, THERE IS LOW CONFIDENCE IN THE INTENSITY FORECAST DUE TO THE LOWER SEA SURFACE TEMPERATURES.

THE AREA OF CONVECTION (INVEST 94W) PREVIOUSLY LOCATED NEAR 14.4N 129.3E IS NOW LOCATED NEAR 16.7N 128.4E, APPROXIMATELY 740 KM EAST-SOUTHEAST OF APARRI, PHILIPPINES. ANIMATED MSI DEPICTS A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH PERSISTENT CONVECTION SHOWING SIGNS OF BANDING AND CONSOLIDATION AS IT CONTINUES DRAWING INTO THE LLCC. THE CONVECTION APPEARS TO REMAIN GREATER THAN 75 KM FROM THE LLCC. THE AFOREMENTIONED MICROWAVE IMAGE REVEALS A POCKET OF DEEP CONVECTION DISPLACED TO THE NORTH OF THE LLCC, AND MINOR FORMATIVE BANDING ALONG THE SOUTHERN AND EASTERN PERIPHERIES. AN 100133Z ASCAT-B PASS REVEALS THAT THE CENTER REMAINS OBLONG, BUT THE IMMEDIATELY SURROUNDING WINDS HAVE STRENGTHENED TO PRIMARILY 15-20 KTS. THE STRONGEST WINDS (30-40 KTS) REMAIN GREATER THAN 90 KM FROM THE LLCC. ENVIRONMENTAL ANALYSES INDICATE MARGINALLY FAVORABLE CONDITIONS FOR DEVELOPMENT CHARACTERIZED BY WARM SST, AND POLEWARD OUTFLOW ALOFT OFFSET BY HIGH (25-35) VWS ALONG THE WESTERN PERIPHERY. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT INVEST 94W WILL OVERTAKE INVEST 93W AS IT CONSOLIDATES AND STRENGTHENS ALONG ITS NORTHWESTERLY PATH. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH.

THE AREA OF CONVECTION (INVEST 93W) PREVIOUSLY LOCATED NEAR 15.5N 130.8E HAS MERGED WITH INVEST 94W AND IS NO LONGER SUSPECT FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE IN THE NEXT 24 HOURS.

FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 120 NM EITHER SIDE OF A LINE FROM 11.6N 97.1W TO 14.5N 104.4W WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO BE 20 TO 25 KNOTS. METSAT IMAGERY AT 091800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 11.8N 97.5W. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 22 KM/H. 2. REMARKS: MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.

INVEST 91E. TRACK AND INTENSITY GUIDANCE.

10/0430UTC.