02W(MALAKAS) intensifying to Typhoon status by 36h: binary interaction with weaker 03W//Invest 96W and Subtropical 23P(FILI),09/09utc

JTWC IS ISSUING 6HOURLY WARNINGS ON TS 02W(MALAKAS) AND TD 03W. 3HOURLY SATELLITE BULLETINS ARE ISSUED ON BOTH SYSTEMS AND ON SUBTROPICAL TC 23P(FILI).

09/0710UTC.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A CONSOLIDATING SYSTEM WITH DEEPENING CENTRAL CONVECTION OBSCURING THE LOW LEVEL CIRCULATION (LLC) THAT WAS, SIX HOURS AGO, PARTIALLY EXPOSED. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A DEFINED LLC IN THE 090547Z GPM MICROWAVE IMAGE. THE INITIAL INTENSITY OF 45KTS IS BASED ON AN OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE CONVECTIVE IMPROVEMENT. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH MODERATE POLEWARD OUTFLOW AND WARM SST OFFSETTING THE MODERATE TO STRONG VWS. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE STR TO THE NORTHEAST.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS MALAKAS WILL CONTINUE NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE (STR). AFTER 48H, THE CYCLONE WILL JOG SLIGHTLY WESTWARD AND DECELERATE AS IT INTERACTS WITH A SECONDARY CYCLONE (TD 03W) APPROACHING FROM THE SOUTHWEST. AFTERWARD, IT WILL ROUND THE STR AXIS THEN RECURVE NORTHEASTWARD TOWARD IWO TO. THE FAVORABLE ENVIRONMENT WILL FUEL A STEADY INTENSIFICATION TO 80KTS/CAT 1 US BY 48H. AFTERWARD, AS THE CYCLONE ROUNDS THE STR AXIS, DECREASED VWS AND INCREASED POLEWARD OUTFLOW WILL ENHANCE THE FAVORABLE DYNAMICS AND BRING THE CYCLONE TO ITS PEAK INTENSITY OF 95KTS/CAT 2 US BY 72H. AFTER 72H, VWS WILL ONCE AGAIN INCREASE. THIS PLUS THE INFLUX OF COOL DRY AIR WILL BEGIN TO ERODE THE SYSTEM AND BY 120H WILL BE AT 70KTS/CAT 1 US.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH A GRADUAL AND EVEN SPREAD TO 440KM BY 120H. HOWEVER, GIVEN SOME UNCERTAINTY WITH THE IMPACT OF BINARY INTERACTION WITH TD 03W, THERE IS ONLY MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A WEAK AND IRREGULAR SYSTEM WITH FRAGMENTED FORMATIVE BANDS, MOSTLY WRAPPING IN FROM THE NORTH INTO A PARTIALLY EXPOSED LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE PARTIALLY EXPOSED LLC IN THE MSI LOOP. THE INITIAL INTENSITY OF 25KTS IS BASED ON EQUAL AGENCY AND AUTOMATED DVORAK ESTIMATES AND SUPPORTED BY NEARBY SURFACE OBSERVATIONS INCLUDING WIND AND MSLP REPORTS FROM GUIUAN ISLAND. ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH MODERATE VWS, MODERATE POLEWARD OUTFLOW, AND WARM SST. THE CYCLONE IS QUASI-STATIONARY (QS) IN THE PHILIPPINE SEA WHERE IT IS EMBEDDED IN A SHALLOW TROUGH WITH EASTERLY TRADEWINDS TO THE NORTH AND A BELT OF WESTERLIES TO THE SOUTH.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TD 03W WILL REMAIN IN A QS MODE IN THE WEAK STEERING ENVIRONMENT UP TO 36H. AFTERWARD IT WILL BEGIN TO TRACK NORTHEASTWARD AS IT GETS PULLED INTO AN APPROACHING CYCLONE THAT IS BIGGER AND STRONGER (TS 02W). THIS BINARY INTERACTION WILL INHIBIT ANY SIGNIFICANT DEVELOPMENT OF TD 03W RESULTING IN WEAK INTENSIFICATION TO A PEAK OF 40KTS BY 36H AND SUSTAINED, AT BEST, THROUGH THE REMAINDER OF ITS LIFESPAN AS A TC. BY 72H, TD 03W WILL BEGIN TO BE ABSORBED BY TS 02W AND BY 96H, WILL LOSE ITS CIRCULATION AND BECOME EMBEDDED IN THE SOUTHERN FEEDER BAND OF THE LARGER AND STRONGER CYCLONE.

MODEL DISCUSSION: NUMERICAL MODELS ARE WIDELY SPREAD UP TO 36H; HOWEVER, AFTER 36H, THE MAJORITY OF THE MEMBERS TRACK THE VORTEX NORTHEASTWARD. GIVEN THE LARGE VARIABILITY IN THE FIRST 36HRS, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.

THE AREA OF CONVECTION (INVEST 23P) PREVIOUSLY LOCATED NEAR 25.9S 167.6E IS NOW LOCATED NEAR 25.3S 169.2E, APPROXIMATELY 425 KM SOUTHEAST OF NOUMEA, NEW CALEDONIA. THE SYSTEM IS CURRENTLY CLASSIFIED AS A SUBTROPICAL STORM, GENERALLY CHARACTERIZED AS HAVING BOTH TROPICAL AND MID-LATITUDE CYCLONE FEATURES. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND 090301Z AMSR2 36GHZ MICROWAVE IMAGE DEPICT A LOW-LEVEL CENTER THAT IS FULLY EXPOSED, WITH SHEARED CONVECTION TO THE SOUTHEAST. A RECENT ASCAT IMAGE SHOWS MAXIMUM SURFACE WINDS AT 35 KNOTS TO THE SOUTHEAST. ENVIRONMENTAL ANALYSIS DEPICTS AN UNFAVORABLE ENVIRONMENT FOR REDEVELOPMENT OF A TROPICAL CYCLONE CHARACTERIZED BY STRONG (25KTS+) VERTICAL WIND SHEAR (VWS) WITH 23P SLOWLY EMBEDDING ITSELF IN THE UPPER LEVEL WESTERLIES AND COOL (25-26C) SEA SURFACE TEMPERATURES. WITH 23P EMBEDDING ITSELF IN THE MID-LATITUDE JET, GLOBAL MODELS AGREE THAT 23P WILL TRANSITION TO AN EXTRATROPICAL SYSTEM AS A MAJOR SHORT WAVE TROUGH APPROACHES FROM THE SOUTHWEST IN 52-70 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 33 TO 38 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 993 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.