WDPN31 PGTW 150300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (KAI-TAK) WARNING 
NR 11//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 14W (KAI-TAK), LOCATED APPROXIMATELY 210 NM 
NORTH-NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 
13 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY (MSI) SHOWS THE LOW-LEVEL CIRCULATION CENTER (LLCC) 
CURRENTLY TRACKING OVER THE NORTHEASTERN TIP OF LUZON. THE SYSTEM 
HAS NOT ONLY MAINTAINED ITS CENTRAL CONVECTIVE STRUCTURE BUT ALSO 
CONTINUES TO DEVELOP FORMATIVE FEEDER BANDS FROM THE NORTH AND WEST, 
AS EVIDENT IN A 142225Z CORIOLIS 37 GHZ IMAGE. THE CURRENT POSITION 
IS BASED ON THE AFOREMENTIONED IMAGERY, ALONG WITH THE PGTW FIX IN 
THE MSI, WITH GOOD CONFIDENCE. THE PAST SIX HOUR STORM MOTION 
INDICATES THAT TS 14W HAS FINALLY PULLED OUT OF ITS SOUTHERN DIP 
THAT WAS PREVIOUSLY OBSERVED. THE CURRENT INTENSITY IS BASED ON THE 
HIGHER SIDE OF DVORAK ESTIMATES, RANGING FROM 45-55 KNOTS FROM RJTD 
AND PGTW/KNES RESPECTIVELY, DUE TO THE IMPROVED FEEDER BAND 
STRUCTURE AND MAINTAINED CENTRAL CONVECTION. UPPER-LEVEL ANALYSIS 
AND ANIMATED WATER VAPOR IMAGERY INDICATE THE TROPICAL UPPER-
TROPOSPHERIC TROUGH CELL, PREVIOUSLY LOCATED NORTH OF THE SYSTEM, IS 
NOW POSITIONED OFF TO THE NORTHWEST. THIS IS PROVIDING FOR A SLIGHT 
INCREASE IN POLEWARD OUTFLOW AND MAY BE THE CAUSE OF THE RECENT 
IMPROVED STRUCTURE. EQUATORWARD OUTFLOW REMAINS ROBUST AND VERTICAL 
WIND SHEAR SEEMS TO HAVE SLIGHTLY EASED TO 10-15 KNOTS FROM THE 
NORTHEAST. TS 14W IS BEING STEERED IN A 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 ON A NORTHWESTWARD TRAJECTORY 
AS THE SHALLOW MID-LATITUDE TROUGH, LOCATED OVER EASTERN CHINA, 
PRODUCES A SLIGHT WEAKNESS IN THE STR. ANIMATED WATER VAPOR IMAGERY 
AND 200 MB STREAMLINE FLOW FROM NUMERICAL MODEL GUIDANCE SUGGEST THE 
MAXIMUM JET STREAK IS CURRENTLY EXITING THE BASE OF THE TROUGH. 
THEREFORE, FURTHER DEEPENING OF THIS TROUGH IS NOT EXPECTED AND THE 
STR SHOULD BEGIN TO BUILD BACK IN OVER THE SYSTEM AS IT LIFTS OUT OF 
TH AREA AND LONGWAVE ZONAL FLOW TEMPORARILY SETS IN. TS 14W SHOULD 
GRADUALLY INTENSIFY AS IT FEEDS OFF OF WARM SEA SURFACE TEMPERATURES 
(27-29 DEGREES CELSIUS) AND OUTFLOW SLIGHTLY IMPROVES. THE SYSTEM 
SHOULD PEAK AT TAU 36 AND POSSIBLY REACH SLIGHTLY HIGHER WIND SPEEDS 
BEFORE MAKING LANDFALL SHORTLY BEFORE TAU 48. AFTER LANDFALL 
DETERIORATION OF THE LLCC WILL COMMENCE DUE TO FRICTIONAL FORCES AS 
IT DRIFTS FURTHER INLAND BY TAU 72.
   C. TS 14W WILL HAVE DISSIPATED OVERLAND BY TAU 96. THE OBJECTIVE 
AID GUIDANCE CONTINUES TO CONVERGE TOWARDS AN OVERALL NORTHWESTWARD 
TRACK WITH THE EXCEPTION OF THE JGSM REMAINING AS THE LEFT MOST 
OUTLIER. BASED ON THE GOOD AGREEMENT IN THE GUIDANCE THERE IS HIGH 
CONFIDENCE IN THE TRACK FORECAST. THIS FORECAST IS SLIGHTLY FASTER 
THAN CONSENSUS TO OFFSET THE SLOWER NOGAPS AND GFDN.//
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