WDXS31 PGTW 130900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (ILSA) WARNING NR 019// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 18.7S 118.7E INITIAL INTENSITY: 130 KTS GEOGRAPHIC REFERENCE: 337 NM NORTHEAST OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 50 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL CYCLONE (TC) 18S HAS RAPIDLY INTENSIFIED 40 KNOTS FROM 90 KNOTS AT 120600Z TO THE CURRENT INTENSITY OF 130 KNOTS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A 9NM EYE WITH A PLUS 11.3C EYE TEMPERATURE AS OF 130830Z. A 130527Z AMSR2 89GHZ MICROWAVE IMAGE REVEALS A COMPACT, 105NM DIAMETER CORE WITH SPIRAL BANDING OVER THE NORTHERN AND SOUTHERN QUADRANTS. BEDOUT ISLAND, WHICH IS LOCATED ABOUT 58NM SOUTH-SOUTHEAST OF THE CENTER, IS REPORTING MAXIMUM SUSTAINED WINDS OF 46 KNOTS (10-MINUTE AVERAGE) GUSTING TO 57 KNOTS THUS FAR. RECENT RADAR IMAGERY FROM PORT HEDLAND SHOWS A SOUTHWARD TO SOUTH-SOUTHEASTWARD TRACK MOTION TOWARD BEDOUT ISLAND OVER THE PAST TWO HOURS. OVERALL, ENVIRONMENTAL CONDITIONS ARE HIGHLY FAVORABLE WITH RADIAL OUTFLOW ALOFT AND ENHANCED POLEWARD OUTFLOW INTO A MAJOR SHORTWAVE TROUGH APPROACHING WESTERN AUSTRALIA. ADDITIONALLY, SST VALUES ARE VERY WARM AT 30-31C WITH HIGH OCEAN HEAT CONTENT. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EIR IMAGERY, AMSR2 IMAGE AND RADAR IMAGERY. THE INITIAL INTENSITY OF 130 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON CONCURRENT AGENCY DVORAK ESTIMATES OF T6.5 AS WELL AS CIMSS RAW T-NUMBERS OF 6.7 (130-135 KNOTS). A 130525Z AMSR2 WINDSPEED IMAGE INDICATES MAXIMUM WINDS OF 121 KNOTS AND WAS ALSO USED TO MODIFY THE WIND RADII IN CONJUNCTION WITH LIMITED SURFACE OBSERVATIONS FROM BEDOUT ISLAND. ADT AND AIDT ESTIMATES REMAIN TOO LOW AT 90-97 KNOTS BUT HAVE JUST SWITCHED TO AN EYE SCENE AT 130630Z WITH RAW T-NUMBERS JUMPING TO 6.7. INITIAL WIND RADII BASIS: AMSR2 WINDSPEED IMAGE AND LIMITED SURFACE OBSERVATIONS CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE EAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T6.5 - 127 KTS KNES: T6.5 - 127 KTS APRF: T6.5 - 127 KTS CIMSS SATCON: 105 KTS AT 130543Z CIMSS ADT: 90 KTS AT 130530Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 10-15 KTS SST: 30-31 CELSIUS OUTFLOW: STRONG RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: AFTER PASSING OVER BEDOUT ISLAND, TC 18S IS EXPECTED TO MAKE LANDFALL NEAR TAU 09 (131500Z). ENVIRONMENTAL CONDITIONS REMAIN HIGHLY CONDUCIVE THEREFORE ADDITIONAL INTENSIFICATION TO ABOUT 140 KNOTS IS ANTICIPATED OVER THE NEXT NINE HOURS. AFTER LANDFALL, TC 18S WILL RECURVE SHARPLY SOUTHEASTWARD TO EAST-SOUTHEASTWARD AS IT INTERACTS WITH THE MAJOR SHORTWAVE TROUGH AND EVENTUALLY ACCELERATES WITHIN THE MIDLATITUDE WESTERLIES. RAPID WEAKENING IS EXPECTED WITH DISSIPATION BY TAU 48 OVER CENTRAL AUSTRALIA. MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN VERY TIGHT AGREEMENT THROUGH TAU 24 WITH AN 11NM SPREAD IN SOLUTIONS AT TAU 12 AND A 26NM SPREAD IN SOLUTIONS AT TAU 24. AFTER TAU 24, GUIDANCE DIVERGES GRADUALLY WITH INCREASING UNCERTAINTY ASSOCIATED WITH THE TRACK WITHIN THE MIDLATITUDE WESTERLIES OVER LAND. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH INTENSITY 0 - 72 HR: MEDIUM// NNNN