WDPN31 PGTW 252100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (MINDULLE) WARNING NR 014// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 18.5N 137.0E INITIAL INTENSITY: 105 KTS GEOGRAPHIC REFERENCE: 448 NM SOUTH-SOUTHWEST OF IWO TO MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 06 KTS SIGNIFICANT WAVE HEIGHT: 36 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY INDICATES THE NASCENT RAGGED EYE FEATURE HAS STRUGGLED TO MAINTAIN ITSELF LEADING UP TO THE 2518Z WARNING TIME, HOWEVER, IN SUBSEQUENT FRAMES IT APPEARS TO ONCE AGAIN BE MAKING AN EFFORT TO CLEAR OUT AND BECOME MORE SYMMETRIC. THIS SUGGESTS ANOTHER ROUND OF INTENSIFICATION MIGHT BE COMMENCING. UNFORTUNATELY, THERE HAS BEEN NO USEFUL MICROWAVE IMAGERY TO HELP ANALYZE THE LOWER LEVEL INNER CORE DEVELOPMENT SINCE THE 2509Z TIME. THE INITIAL INTENSITY WAS LOWERED TO 105 KNOTS BASED ON AGENCY DVORAK FIXES WITH PGTW AND KNES DATA-T VALUES DROPPING TO T5.5 AS THE RAGGED EYE COOLED AT FIX TIME. AUTOMATED FIX ESTIMATES HAVE BEEN SOMEWHAT CHAOTIC AND LOW-BIASED, SO THEY WERE NOT CONSIDERED DURING THIS ANALYSIS. THE INITIAL POSITION WAS ALSO BASED ON AGENCY FIXES. THE ASCENDING ASCAT PASSES SIX HOURS AGO MISSED THE CENTER AS WELL, SO WIND STRUCTURE WAS PRIMARILY BASED ON PERSISTENCE AND OBJECTIVE BEST TRACK GUIDANCE. A SENTINAL-1 SAR COLLECTION IS SCHEDULED IN THE NEXT FEW HOURS, WHICH WILL HOPEFULLY PROVIDE MORE DATA FOR THE 2600Z ANALYSIS CYCLE. INITIAL WIND RADII BASIS: PERSISTENCE AND OBJECTIVE BEST TRACK CURRENT STEERING MECHANISM: COMPETING STEERING PATTERN BETWEEN AN EAST-WEST ORIENTED EXTENSION OF THE STR LYING ALONG THE 30N LATITUDE, AND A DEVELOPING STR CENTERED NEAR GUAM. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T6.0 - 115 KTS RJTD: T5.5 - 102 KTS RCTP: T5.5 - 102 KTS KNES: T6.0 - 115 KTS CIMSS SATCON: 87 KTS AT 251635Z CIMSS ADT: 69 KTS AT 251740Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 5-10 KTS SST: 30-31 CELSIUS OUTFLOW: STRONG RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TYPHOON 20W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD THROUGH TAU 48, AND SHOULD BEGIN TO SLOW AS A COMPETING STEERING ENVIRONMENT SETS UP. THE STRENGTHENING STR CENTERED NEAR GUAM IS CREATING A TIGHTENING GRADIENT ON THE SOUTHEAST SIDE OF THE CIRCULATION, TENDING TO PUSH THE SYSTEM TO THE NORTH. HOWEVER, A BUILDING RIDGE TO THE NORTH WILL HINDER THE FORWARD MOTION. A SERIES OF MID-LATITUDE TROUGHS TRANSITING TO THE NORTH WILL ERODE THE NORTHERN RIDGE, SUCH THAT BY AROUND TAU 48, THE PRIMARY STEERING MECHANISM WILL SHIFT TO THE STRONG STR TO THE EAST. AS A RESULT, TY 20W SHOULD TURN NORTHEASTWARD AND ACCELERATE. THE SYSTEM HAS ABOUT ANOTHER 12 TO 24 HOURS TO FURTHER INTENSIFY BEFORE THE SYSTEM MOVES OVER AN AREA OF COOLER OHC IN ITS PATH. THE SLOWING MOTION SHOULD ACCENTUATE THE UPWELLING OF COOLER WATERS AND LIMITING FURTHER INTENSIFICATION BEYOND TAU 24. IN THE NEAR-TERM, THE SYSTEM SHOULD BE ABLE TO PUSH BACK THE WEAK NORTHWESTERLY FLOW CURRENTLY IMPINGING ON THE NORTHWEST SIDE OF THE SYSTEM, AND IMPROVE THE OVERALL OUTFLOW. THE SYSTEM IS EXPECTED TO PEAK AT 130 KNOTS AT TAU 24. THEN THE SYSTEM WILL STEADILY WEAKEN AS IT STRUGGLES AGAINST DECREASED OHC, DECREASED OUTFLOW ALOFT AND INCREASING MID-LEVEL SHEAR. ONCE THE SYSTEM STARTS TO ACCELERATE TO THE NORTHEAST, SSTS REMAIN HIGH ENOUGH TO OFFSET NEGATIVE FACTORS, ALLOWING FOR A SLOW WEAKING TREND. ALTHOUGH THE PRIMARY MODEL GROUPING KEEPS THE CENTER TRACK EAST OF JAPAN, THERE IS STILL UNCERTAINTY IN THE TRACK, AND THE EXPANSIVE 35 KNOT WIND FIELD COVERS MUCH OF EASTERN HONSHU, WITH STORM FORCE WINDS POSSIBLE. MODEL DISCUSSION: MODEL SOLUTIONS ARE IN MODERATE AGREEMENT, BOTH IN ALONG AND CROSS TRACK SPREAD. THE FORECAST TRACK IS THEREFORE PLACED CLOSE TO THE MULTI-MODEL CONSENSUS. RAPID INTENSITY RIPA AID STILL INDICATES RI POSSIBILITY OVER THE NEXT 24 HOURS. INTENSITY FORECAST IS ALSO ALONG THE CONSENSUS BLEND. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN