MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (HAIMA) WARNING NR 14// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 25W (HAIMA), LOCATED APPROXIMATELY 644 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A TIGHTLY SPIRALED SYSTEM WITH A 15 NM WELL-DEFINED EYE FEATURE GIVING HIGH CONFIDENCE TO THE INITIAL POSITION. A PREVIOUS 171638Z AMSR2 89 GHZ IMAGE SHOWED AN OUTER RING OF DEEP CONVECTION SURROUNDING THE INNER EYE SUGGESTING AN EYEWALL REPLACEMENT CYCLE (ERC) WAS UNDERWAY. HOWEVER, NO RECENT MICROWAVE DATA IS AVAILABLE TO CONFIRM EYEWALL CONTRACTION AND MSI OVER THE LAST SIX HOURS INDICATES EYEWALL EXPANSION, REVERSING THE ERC TREND. THE INITIAL INTENSITY IS ASSESSED AT 120 KNOTS AND IS BASED ON CURRENT INTENSITY DVORAK ESTIMATES RANGING FROM T6.0 TO T6.5 (115 TO 127 KNOTS). UPPER- LEVEL ANALYSIS SHOW EXCELLENT RADIAL OUTFLOW WITH VERY LOW VERTICAL WIND SHEAR. SEA SURFACE TEMPERATURES ARE ALSO VERY FAVORABLE NEAR 30 CELSIUS. CURRENTLY TY HAIMA IS TRACKING NORTHWEST ALONG THE PERIPHERY ON A DEEP LAYERED SUBTROPICAL RIDGE POSITIONED TO THE NORTH. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING BULLETIN. B. TY HAIMA WILL CONTINUE TO TRACK NORTHWESTWARD ALONG THE SUBTROPICAL RIDGE AS IT BUILDS EXTENDING WESTWARD. THE INTENSITY IS EXPECTED TO PULSATE AROUND 120 KNOTS OVER THE NEXT 12 TO 24 HOURS AS THE SECONDARY EYE FEATURE OBSERVED IN THE AFOREMENTIONED MICROWAVE IMAGE REORGANIZES WITH THE POTENTIAL FOR ERC IN THE NEAR FUTURE. ANOTHER PERIOD OF SLIGHT INTENSIFICATION IS LIKELY AFTER TAU 24 AS FAVORABLE CONDITIONS PERSIST, REACHING A PEAK INTENSITY OF 125 KNOTS. LAND INTERACTION WITH THE NORTHERN COAST OF LUZON IS EXPECTED NEAR TAU 42 SETTING IN MOTION A WEAKENING TREND EXPECTED TO CONTINUE THROUGH THE REMAINDER OF THE FORECAST PERIOD. C. BEYOND TAU 72 TY HAIMA WILL BEGIN TO ROUND THE STEERING RIDGE AXIS SHIFTING FROM A NORTHWESTWARD TRACK TO A NORTH-NORTHEASTWARD TRACK. AROUND TAU 90 THE SYSTEM IS EXPECTED TO MAKE LANDFALL EAST OF HONG KONG AND TRACK INLAND AS IT COMPLETES ITS TRACK SHIFT. AVAILABLE MODEL GUIDANCE SHOWS VERY GOOD AGREEMENT THROUGH TAU 72. MODEL SOLUTIONS BEYOND TAU 72 SHOW SOME DIVERGENCE IN TRACK MOTION AS THE SYSTEM ROUNDS THE RIDGE AXIS OVER LAND, BUT ALL AVAILABLE SOLUTIONS ARE SHOWING A NORTHWARD CURVE AROUND THE STEERING RIDGE. DUE TO THE GOOD AGREEMENT IN MODELS UP TO TAU 72 AND RELATIVELY GOOD AGREEMENT AS IT MAKES LANDFALL, THERE IS OVERALL HIGH CONFIDENCE IN THE FORECAST TRACK.// NNNN NNNN