WDPN31 PGTW 050900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 07W (SEVEN) WARNING NR 003// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 19.5N 123.5E INITIAL INTENSITY: 30 KTS GEOGRAPHIC REFERENCE: 548 NM EAST-SOUTHEAST OF HONG KONG MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 21 KTS SIGNIFICANT WAVE HEIGHT: 14 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS FRAGMENTED CONVECTIVE BANDING OVER THE NORTHERN SEMICIRCLE WRAPPING INTO THE WESTERN QUADRANT OF A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). A 050528Z AMSR2 89GHZ MICROWAVE IMAGE INDICATES WEAK OVERALL STRUCTURE ALTHOUGH SHALLOW BANDING HAS IMPROVED AND NOW WRAPS INTO A DEFINED, SMALL LLCC THUS THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON RECENT ASCAT DATA AND THE KNES DVORAK ESTIMATE. THE ENVIRONMENT REMAINS FAVORABLE WITH MODERATE EQUATORWARD OUTFLOW, WARM SST AND LOW VERTICAL WIND SHEAR. POLEWARD OUTFLOW IS WEAK DUE TO A LACK OF A POLEWARD OUTFLOW MECHANISM. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) ENTRENCHED TO THE NORTH AND NORTHEAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T1.5 - 25 KTS RJTD: T1.5 - 25 KTS KNES: T2.0 - 30 KTS FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 5-10 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: NOT APPLICABLE 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TD 07W IS FORECAST TO TRACK QUICKLY NORTHWESTWARD THROUGH THE FORECAST PERIOD ALONG THE SOUTHWESTERN PERIPHERY OF THE STRONG STR WITH LANDFALL OVER SOUTHEAST CHINA JUST AFTER TAU 24. TD 07W CONTINUES TO STRUGGLE GENERATING AND MAINTAINING ORGANIZED DEEP CONVECTION DUE TO THE QUICK TRACK SPEEDS AND WEAK NATURE OF THE LLCC. SLIGHT INTENSIFICATION IS EXPECTED BY TAU 12 WITH A PEAK OF 35 KNOTS, HOWEVER, FAVORABLE CONDITIONS SHOULD DEGRADE AFTER TAU 12 AS VWS INCREASES TO 25 KNOTS LEADING TO STEADY WEAKENING AND DISSIPATION OVER LAND BY TAU 36. MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT AT TAU 12 WITH A 50NM SPREAD IN SOLUTIONS BUT DIVERGES BY TAU 24 WITH A 130NM SPREAD IN SOLUTIONS SO OVERALL MEDIUM CONFIDENCE IN THE TRACK FORECAST. THERE IS ALSO MEDIUM CONFIDENCE IN THE INTENSITY FORECAST WITH SOME UNCERTAINTY IN THE PEAK INTENSITY NEAR TAU 12 AS THE SYSTEM TRANSITS SOUTH OF TAIWAN. HOWEVER, THIS FORECAST IS IN LINE WITH HWRF AND THE JTWC INTENSITY CONSENSUS GUIDANCE. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM// NNNN