WDXS31 PGTW 282100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 01S (ONE) WARNING NR 001// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 10.5S 95.1E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 147 NM WEST-NORTHWEST OF COCOS ISLANDS MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 06 KTS SIGNIFICANT WAVE HEIGHT: 12 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS CONSOLIDATING SYSTEM, WITH PERSISTENT DEEP CONVECTION AND IMPROVED CONVECTIVE BANDING OVER THE EASTERN AND SOUTHERN SEMICIRCLE. A 281532Z METOP-B AMSU 89GHZ MICROWAVE PASS INDICATES THE DEEP CONVECTION IS NOW WRAPPING INTO THE ASSESSED LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON AN EXTRAPOLATED 281535Z METOP-B ASCAT PASS. ENVIRONMENTAL ANALYSIS INDICATES THE SYSTEM IS IN A FAVORABLE AREA FOR DEVELOPMENT WITH WARM (28-30C) SEA SURFACE TEMPERATURES AND MODERATE (20-25KTS) VERTICAL WIND SHEAR, WHICH IS BEING OFFSET BY VIGOROUS POLEWARD OUTFLOW. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE PGTW DVORAK ESTIMATE, AFOREMENTIONED ASCAT, AND A BULLSEYE 281138Z SMOS PASS, WHICH SHOWED A AREA OF 35 KNOT OR HIGHER WINDS TO THE SOUTHEAST OF THE LLCC. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP LAYER SUBTROPICAL RIDGE (STR) AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 20-25 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: WHILE TC 01S HAS TRACKED GENERALLY SOUTHEASTWARD OVER THE PAST 6-12 HOURS UNDER THE INFLUENCE OF THE STR TO THE EAST, IT IS FORECAST TO TRACK SOUTH-SOUTHWESTERLY FOR THE NEXT 36 HRS AS THE ORIENTATION OF THE STEERING RIDGE SHIFTS TO A MORE SOUTHWEST-NORTHEAST AXIS. AS THE SYSTEM TRACKS TO THE SOUTH, IT IS FORECAST TO INTENSIFY TO A PEAK OF 45 KNOTS AS THE ROBUST POLEWARD CONTINUES TO OFFSET THE MODERATE SHEAR. HOWEVER BY TAU 36 THE UPPER-LEVEL PATTERN SHIFTS ONCE MORE, OUTFLOW TO THE SOUTH WILL BE REDUCED AND EFFECTIVE SHEAR WILL INCREASE, LEADING TO A SLOW WEAKENING TREND THROUGH THE REMAINDER OF THE FORECAST. AS THE SYSTEM WEAKENS AND BECOMES MORE SHALLOW, IT WILL BEGIN TRACKING TO A MORE WESTWARD DIRECTION INFLUENCED BY A LOW TO MID-LEVEL ANTICYCLONE POLEWARD OF THE CENTER WHICH BECOMES THE MORE DOMINATE STEERING FEATURE. AFTER TAU 48 TC 01S WILL BEGIN TO MOVE WESTWARD INTO AN ENVIRONMENT WHICH WILL BE MUCH LESS CONDUCIVE FOR FURTHER DEVELOPMENT AS VERTICAL WIND SHEAR INCREASES ALONG WITH A SUBSTANTIAL IN FLUX OF DRY AIR. THESE IMPEDING FACTORS WILL RESULT IN THE SYSTEM DECEASING BELOW WARNING CRITERIA BETWEEN TAU 72 AND TAU 96. MODEL DISCUSSION: THE JTWC TRACK IS CLOSE TO THE MULTI-MODEL CONSENSUS THROUGH 48 HOURS AND SLIGHTLY RIGHT OF CONSENSUS THROUGH OUT THE REST OF THE FORECAST. JTWC INTENSITY FORECAST IN SLIGHTLY HIGHER THAN THE MULTI-MODEL CONSENSUS BETWEEN TAU 24-36 BEFORE GRADUALLY DECREASING DUE TO IMPEDING ENVIRONMENTAL FACTORS BEYOND 48 HRS. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN