WDPN32 PGTW 090900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (MUIFA) WARNING NR 012// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 19.2N 128.7E INITIAL INTENSITY: 55 KTS GEOGRAPHIC REFERENCE: 441 NM SOUTH OF KADENA AB MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 10 KTS SIGNIFICANT WAVE HEIGHT: 21 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A TIGHT CORE OF CONVECTIVE TOWERS WITH BANDS OF DEEP CONVECTION STRUGGLING TO CONSOLIDATE THE WESTERN FLANK OF THE LLCC. A 090446Z AMSR2 89GHZ MICROWAVE IMAGE SHOWS THAT 14W IS IN-FACT IMPROVING ITS CORE STRUCTURE AND DEVELOPING EYE-LIKE FEATURES WITH INCREASING FREQUENCY. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON MSI AND AMSR2 IMAGERY. WE ARE STILL SUFFERING A DATA OUTAGE SOMEWHERE UPSTREAM, AND AS A RESULT OBJECTIVE FIX DATA IS NOT CONSISTENT AND CIMSS SHEAR ANALYSIS IS UNAVAILABLE DUE TO THE OUTAGE, AS A RESULT ENVIRONMENTAL ASSESSMENT IS LARGELY BASED ON MODEL DERIVED VALUES, AND IS FAIRLY LOW CONFIDENCE. BASED ON AGENCY DVORAK INTENSITY ESTIMATES INDICATING A RANGE FROM 42-65 KTS AND A SLIGHTLY OLDER SIMSS ADT SHOWING 55 KTS, THE INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH MEDIUM CONFIDENCE. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: WEST PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) TO THE EAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.0 - 65 KTS RJTD: T2.5 - 35 KTS KNES: T4.0 - 65 KTS CIMSS SATCON: 53 KTS AT 090211Z CIMSS ADT: 55 KTS AT 090300Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 0-5 KTS SST: 30-31 CELSIUS OUTFLOW: MODERATE POLEWARD AND EQUATORWARD OTHER FACTORS: MID-LEVEL WESTERLY SHEAR ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 14W CONTINUES TO TRACK NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR TO THE EAST. WE HAVE ALREADY SEEN INTERMITTENT SIGNS OF EYE-LIKE FORMATION AND OVER THE NEXT 12 HOURS THE SYSTEM WILL CONTINUE TO DEVELOP, FORM AND MAINTAIN AN EYE AS IT REACHES TYPHOON STRENGTH. ANIMATED UPPER LEVEL WATER VAPOR IMAGERY INDICATES THAT A TROPICAL UPPER TROPOSPHERE TROUGH (TUTT) HAS BEEN SUPPRESSING CONVECTION ON THE WESTERN SIDE OF 14W, BUT AS THIS FEATURE CONTINUES TO MOVE WESTWARD OVER THE COMING HOURS, THE SYSTEM WILL BE FREE TO FULLY DEVELOP. AS THE SYSTEM CONTINUES TO INTENSIFY TO A POSSIBLE PEAK OF 115 KTS BY TAU 48, THE STEERING FLOW SURROUNDING THE SYSTEM BECOMES EERILY SIMILAR TO 12W AND WITH A SIMILAR RESULT. A NEAR EQUATORIAL RIDGE (NER) WILL SET UP TO THE SOUTH, A STR WILL BAR THE PATH TO THE NORTHEAST AND ANOTHER STR WILL PREVENT ESCAPE TO THE NORTHWEST, AS THIS SETS UP, TRACK SPEEDS WILL SLOW CONSIDERABLY THROUGH TAU 72. THERE REMAINS A SIZABLE OHC COLD POOL EAST OF TAIWAN THAT WILL CAUSE SIGNIFICANT WEAKENING AS THE SYSTEM PASSES OVER IT. AS A RESULT, DOWN TRACK INTENSITY WILL HAVE AN INVERSE RELATIONSHIP TO THE DURATION OF TIME THE SYSTEMS IS IN THIS COLD POOL. THEREFOR, BY TAU 96, AS THE SYSTEM FINALLY REGAINS NORTHWARD PROGRESSION THANKS TO A PASSING MID LATITUDE TROUGH, 14W WILL BE ON A WEAKENING TREND. AS THE SYSTEM CONTINUES INTO THE EAST CHINA SEA BY TAU 120, IT WILL HAVE LOST A SIGNIFICANT PORTION OF ITS INTENSITY, BUT WILL LIKELY STILL BE A TYPHOON STRENGTH TROPICAL CYCLONE. MODEL DISCUSSION: NUMERICAL MODEL CROSS TRACK AGREEMENT REMAINS SOLID THROUGH TAU 72, HOWEVER, AS DISCUSSED ABOVE THE COMPETING STEERING ENVIRONMENT CREATES SIGNIFICANT ALONG TRACK DISCREPANCIES AFTER TAU 48, AS VARIOUS MODELS TRY TO RESOLVE THE STEERING FLOW. FOR THIS REASON, THE INITIAL JTWC FORECAST TRACK IS PLACED WITH HIGH CONFIDENCE, AND THE EXTENDED TRACK FORECAST IS PLACED WITH LOW CONFIDENCE. RELIABLE MODEL INTENSITY GUIDANCE IS IN GOOD AGREEMENT WITH ALL MEMBERS SHOWING RAPID INTENSIFICATION (RI) THROUGH TAU 36 - TAU 48 AFTER WHICH INTENSITIES STAGNATE AND EVENTUALLY FALL THROUGHOUT THE REMAINING FORECAST PERIOD. WHILE THE GENERAL INTENSITY TREND REMAINS CONSISTENT, THE EXTENT OF THE INITIAL RI PHASE IS NOT, THE MAIN FACTOR INFLUENCING THE MODEL SPREAD IS THE DURATION AND SOUTHWARD EXTENT THE SYSTEM IS QS OFF THE COAST OF TAIWAN. FOR THESE REASONS THE JTWC INTENSITY FORECAST IS PLACED WITH MEDIUM CONFIDENCE. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN