WDPN31 PGTW 280300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (KONG-REY) WARNING 
NR 09//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 14W (KONG-REY), LOCATED APPROXIMATELY 235 NM
SOUTH-SOUTHEAST OF TAIPEI, TAIWAN, HAS TRACKED NORTH-NORTHWESTWARD 
AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL 
SATELLITE IMAGERY SHOWS FLARING DEEP CONVECTION AROUND THE LOW LEVEL 
CIRCULATION CENTER (LLCC) WITH THE BULK OF THE DEEP CONVECTION 
SPREAD ACROSS THE SOUTHERN SEMI-CIRCLE. A 272203Z TRMM 37GHZ 
MICROWAVE IMAGE ALONG WITH A 272205Z CORIOLIS MICROWAVE IMAGE 
REVEALS SEVERAL TIGHTLY WRAPPED CONVECTIVE BANDS ALONG WITH A BROKEN 
AND RAGGED MICROWAVE EYE. THE INITIAL POSITION IS BASED ON THE ABOVE 
ANIMATION AND THE MICROWAVE IMAGES WITH FAIR CONFIDENCE. THE INITIAL 
INTENSITY IS SLIGHTLY HIGHER THAN DVORAK INTENSITY ESTIMATES OF 45 
KNOTS FROM ALL AGENCIES DUE TO THE STRUCTURE SEEN IN THE MICROWAVE 
IMAGES. UPPER LEVEL ANALYSIS INDICATES THE CYCLONE IS SOUTH OF THE 
RIDGE AXIS IN AN AREA OF MODERATE (15-20 KNOT) NORTHEASTERLY 
VERTICAL WIND SHEAR (VWS) WHICH IS BEING OFFSET BY GOOD WESTWARD AND 
EQUATORWARD OUTFLOW. TS 14W IS CURRENTLY TRACKING ALONG THE 
PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE. 
   B. TS 14W IS EXPECTED TO CONTINUE TRACKING POLEWARD UNDER THE 
INFLUENCE OF THE STR THROUGH TAU 36. AFTER TAU 36, A MID-LATITUDE 
TROUGH APPROACHING FROM THE NORTHWEST WILL WEAKEN THE STR AND CAUSE 
THE CYCLONE TO RECURVE NORTHEASTWARD. VWS IS EXPECTED TO GRADUALLY 
DIMINISH AS THE SYSTEM DRIFTS NORTH WHICH WILL ALLOW A SLOW 
INTENSIFICATION, PEAKING AT 60 KNOTS BY TAU 24. AFTER TAU 24, THE 
LAND INTERACTION DUE THE CLOSE PROXIMITY TO TAIWAN WILL DISRUPT THE 
LOW LEVEL INFLOW AND START TO WEAKEN THE STORM. THE APPROACHING 
MIDLATITUDE TROUGH AT TAU 36 WILL FURTHER WEAKEN THE SYSTEM AS IT 
ENCOUNTERS INCREASED VWS WITH THE ONSET OF THE STRONG WESTERLIES. 
THIS TROUGH WILL ALSO START TO INDUCE EXTRA-TROPICAL TRANSITION AT 
TAU 48 AND COMPLETED TRANSITION BY TAU 72.
   C. AFTER TAU 72, TS 14W IS EXPECTED TO ACCELERATE NORTHEASTWARD 
ACROSS JAPAN AS A COLD-CORE EXTRA-TROPICAL SYSTEM. NUMERICAL MODEL 
GUIDANCE IS IN FAIR AGREEMENT, WITH THE EXCEPTION OF ECMWF, THROUGH 
THE FORECAST PERIOD WITH ONLY SLIGHT VARIATIONS IN THE EXTENT OF THE 
RECURVE AND TRANSLATIONAL SPEEDS. ECMWF CONTINUES TO DRIVE THE 
SYSTEM INTO TAIWAN AND RAPIDLY WEAKENS IT. THE JTWC FORECAST IS LAID 
CLOSE TO MULTI-MODEL CONSENSUS IN THE EARLY TAUS AND IS SLIGHTLY 
FASTER THAN AND RIGHT OF CONSENSUS DUE TO A KNOWN HISTORICAL BIAS 
AND TO ACCOUNT FOR THE HIGH TERRAIN IN JAPAN, IN THE EXTENDED TAUS. 
HIGH CONFIDENCE REMAINS IN THE FORECAST DUE TO THE TIGHT PACKING OF 
THE MODELS THROUGH THE FORECAST PERIOD.//
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