WDPN31 PGTW 140300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (KAI-TAK) WARNING 
NR 07//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 14W (KAI-TAK), LOCATED APPROXIMATELY 305 NM
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 11 KNOTS 
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY 
DEPICTS AN OVERALL LARGE LOW-LEVEL CIRCULATION CENTER (LLCC) WHICH 
SEEMS TO BE PARTIALLY-EXPOSED OVER THE NORTHEASTERN QUADRANT. THE 
DEEP FLARE OF CONVECTION NOTICED SEVERAL HOURS AGO DURING THE 
DIURNAL MAXIMUM HAS SINCE WEAKENED, AS OBSERVED IN THE WARMING 
CLOUD TOPS IN THE ENHANCED INFRARED IMAGERY. VERTICAL WIND SHEAR 
(VWS) REMAINS MODERATE (15-20 KNOTS) FROM THE NORTHEAST BUT SPEED 
DIVERGENCE, PRODUCED FROM AMPLE EQUATORWARD OUTFLOW, CONTINUES TO 
PROVIDE AN EXHAUST MECHANISM FOR THE DEEP CONVECTION OVER THE 
SOUTHWESTERN QUADRANT OF THE LLCC. TS 14W'S SURFACE CIRCULATION 
CONTINUES TO STRUGGLE IN ACHIEVING SYMMETRY UNDER THESE COMPETING 
INFLUENCES AND MID-LEVEL CIRCULATIONS CAN BE SEEN EXITING 
CYCLONICALLY FROM UNDERNEATH THE STRONG CONVECTION. THE CURRENT 
POSITION WAS BASED ON A 142217Z TRMM 37 GHZ IMAGE. HOWEVER, A MORE 
RECENT 140016Z SSMIS 37 GHZ IMAGE SUGGESTS THE LLCC IS LOCATED NEAR 
18.1N 125.7E, APPROXIMATELY 35 NM NORTH OF THE CURRENT BEST TRACK 
POSITION. SOME SLIGHT ADJUSTMENT WILL BE MADE TO THE CURRENT 
POSITION BUT OVERALL POSITION CONFIDENCE IS STILL GOOD. THE CURRENT 
INTENSITY IS BASED ON THE PGTW DVORAK ESTIMATE OF 45 KNOTS IN 
COMBINATION WITH THE 131800Z SATCON ESTIMATE OF 47 KNOTS. UPPER-
LEVEL ANALYSIS INDICATES THAT TS 14W IS LOCATED APPROXIMATELY 14 
DEGREES EQUATORWARD OF THE SUBTROPICAL RIDGE AXIS AND HAS A POINT 
SOURCE OF DIVERGENCE LESS THEN TWO DEGREES TO THE EAST. 
ADDITIONALLY, UPPER-LEVEL TROUGHING AND CONVERGENCE IS BEING 
INDUCED BETWEEN THIS POINT SOURCE AND A NEAR EQUATORIAL 
ANTICYCLONIC CENTER LOCATED ABOUT 15 DEGREES FURTHER EAST OF THE 
LLCC. ALL OF THIS IS PRODUCING EXCELLENT EQUATORWARD OUTFLOW BUT 
THERE SEEMS TO BE PRESSURE OVER THE EASTERN PORTION. ANIMATED WATER 
VAPOR IMAGERY STILL HINTS TO A SLIGHT CONNECTION TO POLEWARD 
OUTFLOW INTO A TROPICAL UPPER-TROPOSPHERIC TROUGH NORTH OF THE 
SYSTEM. TS 14W IS BEING STEERED IN A GENERAL WEST-NORTHWESTWARD 
DIRECTION UNDER THE INFLUENCE OF THE DEEP-LAYERED SUBTROPICAL RIDGE 
(STR) CENTERED FAR TO THE NORTHEAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TS 14W IS EXPECTED TO CONTINUE TRACKING WEST-NORTHWESTWARD 
ALONG THE SOUTHERN PERIPHERY OF THE DEEP-LAYERED STR FOR THE 
REMAINDER OF THE FORECAST PERIOD. A MID-LATITUDE TROUGH PROPAGATING 
OVER EASTERN CHINA BY TAU 36 MAY SLIGHTLY ERODE THE STEERING STR 
THUS ALLOWING FOR A MORE NORTHWESTWARD TRACK DURING THIS TIME. 
HOWEVER, THE TROUGH SEEMS TO BE SHALLOW IN NATURE AND THE WESTERN 
EXTENT OF THE PREVIOUSLY BROKEN DOWN STR SHOULD BUILD BACK IN OVER 
SOUTHEASTERN CHINA, AND THE SYSTEM, AFTER TAU 72. GRADUAL 
INTENSIFICATION IS EXPECTED DUE TO COMPETING INFLUENCES OF VERY 
WARM ALONG TRACK SEA SURFACE TEMPERATURES (SST) (28-30 DEGREES 
CELSIUS), MODERATE VWS, AND DIURNAL MAXIMUM CYCLES. THE SYSTEM 
SHOULD REACH TYPHOON INTENSITY BY TAU 36 AND BE ABLE TO MAINTAIN 
SUCH INTENSITIES THROUGH TAU 48 AND INTO LANDFALL NEAR TAU 60. 
OVERALL PEAK INTENSITY MAY NEED TO BE ADJUSTED BEFORE LANDFALL DUE 
TO EXTREMELY WARM SST'S (> 30 DEGREES CELSIUS) BUT VWS DURING THIS 
TIME WILL ALSO PLAY A CRITICAL FACTOR.
   C. AFTER TAU 72 TS 14W WILL BEGIN A SLOW DISSIPATION OVERLAND 
DUE TO FRICTIONAL DRAG AND LOSS OF OCEAN HEAT. NUMERICAL MODEL 
GUIDANCE CONTINUES TO CONVERGE INTO BETTER AGREEMENT UP TO TAU 36, 
AFTER WHICH THE SPREAD INCREASES WITH NOGAPS, JGSM, AND WBAR 
PROVIDING FOR A BIFURCATION BETWEEN THE MORE WESTWARD TRACKERS OF 
THE REMAINING OBJECTIVE AIDS. THE OFFICIAL TRACK FORECAST REMAINS 
SLIGHTLY EQUATORWARD OF CONSENSUS TO OFFSET THE MORE POLEWARD 
TRACKERS BASED ON THE SYNOPTIC ANALYSIS AND FUTURE EVOLUTION OF 
THESE FEATURES. HIGH CONFIDENCE REMAINS IN THE JTWC TRACK 
FORECAST.//
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