MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (LIONROCK) WARNING NR 29// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 12W (LIONROCK), LOCATED APPROXIMATELY 258 NM SOUTHEAST OF KADENA AB, HAS TRACKED SOUTH-SOUTHWESTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED AND MULTISPECTRAL SATELLITE IMAGERY DEPICT A GRADUALLY FILLING EYE WITH CONVECTION CONTINUE TO BE SLIGHTLY SHEARED FROM THE NORTHEAST. A 242231Z SSMIS 91GHZ MICROWAVE IMAGE SHOWS CONVECTIVE BANDING WRAPPING INTO A LOW- LEVEL CIRCULATION CENTER (LLCC) WITH THE DEEPEST CONVECTION TO THE SOUTH AND WEST OF THE LLCC. THE INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE GIVEN THE MICROWAVE IMAGERY. TY 12W CONTINUES TO TRACK TOWARD THE SOUTHWEST DESPITE SOME TROCHOIDAL WOBBLES TO THE SOUTH AND TO THE WEST. DVORAK CURRENT INTENSITY ESTIMATES REMAIN AT 6.0 (PGTW) AND 5.5 (KNES AND RJTD). HOWEVER, THE FINAL T-NUMBER FROM PGTW HAS COME DOWN TO 5.0 GIVEN THE RECENT FILLING OF THE EYE. THUS, THE INITIAL INTENSITY WAS SLIGHTLY REDUCED TO 105 KNOTS. RADIAL OUTFLOW CONTINUES TO BE SOMEWHAT RESTRICTED TO THE NORTH AND EAST BUT GOOD ELSEWHERE. NORTHEASTERLY VERTICAL WIND SHEAR REMAINS LOW (5 TO 15 KNOTS) BUT IS JUST HIGH ENOUGH TO AFFECT THE CONVECTIVE SYMMETRY OF TY 12W. 3. FORECAST REASONING. A. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE, EXCEPT FOR SOME ADJUSTMENTS TO THE INTENSITY FORECAST GIVEN THE LATEST NUMERICAL MODEL GUIDANCE, WITH SOME SLIGHT INTENSIFICATION INDICATED AFTER TY 12W INITIALLY TURNS TOWARD THE NORTHEAST. B. TY 12W WILL CONTINUE MOVING TOWARD THE SOUTHWEST BUT IS BEGINNING TO SLOW DOWN. AFTER A PERIOD OF QUASISTATIONARY DRIFT FROM TAUS 12 TO 24, THE SUBTROPICAL RIDGE AXIS TO THE NORTH WILL RETREAT WESTWARD, GIVING WAY TO A MID-LATITUDE TROUGH THAT WILL DIG OVER THE KOREAN PENINSULA AND ACCELERATE TY 12W TOWARD THE NORTHEAST. ALL NUMERICAL MODEL GUIDANCE INDICATES THIS 180-DEGREE TURN, WITH DIFFERENCES IN WHETHER THE TURN WILL OCCUR TO THE NORTH OR TO THE SOUTH OF THE CURRENT TRACK. HOWEVER, GIVEN THE SMALL HORIZONTAL DISPLACEMENT ASSOCIATED WITH THIS TURN, THE EXACT DIRECTION OF THE INITIAL TURN WILL BE INCONSEQUENTIAL AS THERE IS GOOD CONFIDENCE IN THE EVENTUAL ACCELERATION TOWARD THE NORTHEAST. IN THE SHORT TERM, TY 12W WILL CONTINUE A GRADUAL WEAKENING TREND GIVEN THE SOMEWHAT RESTRICTED OUTFLOW AND LIGHT TO MODERATE VERTICAL WIND SHEAR. FROM TAU 36 TO 72, SOME INTENSIFICATION IS EXPECTED AS THE UPPER-LEVEL POLEWARD OUTFLOW CHANNEL OPENS UP AHEAD OF THE DIGGING MID-LATITUDE TROUGH. C. IN THE EXTENDED TAUS, NUMERICAL MODEL GUIDANCE DIVERGES SIGNIFICANTLY, WITH THE ECMWF AND THE GFS AND JGSM ENSEMBLES SUGGESTING A SHARP TURN TOWARD THE NORTH, WHEREAS MOST OF THE NUMERICAL MODEL GUIDANCE MAINTAINS A MORE SOUTHERLY TRACK TOWARD THE EAST-NORTHEAST. INTERACTION WITH THE STRONG DYNAMICS ASSOCIATED WITH THE MID-LATITUDE TROUGH AND CYCLOGENESIS IN THE SEA OF JAPAN WILL LIKELY CLOSE THE WINDOW OF INTENSIFICATION BEYOND TAU 72. THE OFFICIAL JTWC FORECAST TRACK SUGGESTS A TURN TOWARD THE NORTH, REMAINING TO THE WEST OF CONSENSUS, BUT IT MUST BE STRONGLY EMPHASIZED THAT THE EXTENDED FORECAST IS HIGHLY UNCERTAIN AND THERE IS LOW CONFIDENCE IN THE FORECAST TRACK AND INTENSITY.// NNNN NNNN