Tropical Storm FUNG-WONG Advisory jeu, 18.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (FUNG-WONG) WARNING
NR 03//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 16W (FUNG-WONG), LOCATED APPROXIMATELY 430 NM
EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 10
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A CENTRAL DENSE OVERCAST FEATURE WITH GOOD
BANDING ON THE WESTERN AND SOUTHERN PERIPHERY WRAPPING INTO A
CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC). THE 172331Z AND
172120Z SSMIS MICROWAVE IMAGES CONTINUE TO SHOW INCREASED CENTRAL
DEEP CONVECTION ON THE SOUTHERN SIDE OF THE SYSTEM WITH FRAGMENTED
DEEP CONVECTIVE BANDING ALONG THE WESTERN PERIPHERY. THE CURRENT
POSITION IS BASED ON THE MSI AND AFOREMENTIONED MICROWAVE IMAGES
WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 35 KNOTS
BASED ON DVORAK INTENSITY ESTIMATES FROM PGTW. UPPER-LEVEL ANALYSIS
INDICATES GOOD EQUATORWARD OUTFLOW AND A LOW (5-15 KNOT) VERTICAL
WIND SHEAR ENVIRONMENT, AN ENVIRONMENT FAVORABLE FOR CONTINUED
DEVELOPMENT. FUNG-WONG IS CURRENTLY TRACKING ALONG THE SOUTHWESTERN
PERIPHERY OF A SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING.
   B. OVER THE NEXT 24 HOURS, TS 16W WILL TRACK TO THE NORTHWEST
UNDER THE INFLUENCE OF A WEAKENING STR NORTHEAST OF THE SYSTEM. AS
THE STR BREAKS DOWN, THE SYSTEM WILL CONTINUE TO TRACK NORTHWESTWARD
AND SLOW DOWN UNDER THE SIGNIFICANTLY WEAKER STEERING ENVIRONMENT.
WHILE THERE IS THE POSSIBILITY OF RAPID INTENSIFICATION AS THE
SYSTEM TRACKS THROUGH A FAVORABLE UPPER-LEVEL ENVIRONMENT, THE
PROXIMITY OF THE TS 16W TO THE NORTHEAST COAST OF LUZON COULD
POTENTIALLY LIMIT ITS MAXIMUM WIND SPEED AT THAT TIME.  MODELS ARE
IN FAIR AGREEMENT ON THE TRACK THROUGH TAU 36, WITH SIGNIFICANT
DIVERGENCE IN THE FORECAST TRACK AND SPEED AT TAU 48 AND BEYOND.
JGSM, JENS, AND GFDN FAVOR A FASTER RECURVE SCENARIO AT TAU 48
WHEREAS HWRF AND NAVGEM HAVE THE SYSTEM TRACKING TO THE NORTH UNDER
A SIGNIFICANTLY RE-BUILDING THE STR. GFS, GFS ENSEMBLE AND THE
COAMPS MODELS ARE IN THE MIDDLE WITH A WIDER RECURVE AT TAU 48 THAN
THE JAPANESE MODELS AND A TRACK THROUGH ISHIGAKI-JIMA. THE OFFICIAL
FORECAST IS IN CLOSE ALIGNMENT WITH THE MULTI-MODEL CONSENSUS
THROUGH TAU 48 AND SLIGHTLY POLEWARD THROUGH TAU 72 DUE TO THE MORE
LIKELY SCENARIO THAT THE STR WILL NOT BUILD IN AS STRONGLY AS NAVGEM
ET AL. SUGGESTS.
   C. IN THE EXTENDED FORECAST, A DEEP SUBTROPICAL TROUGH, REACHING
AS FAR SOUTH AS TAIWAN, BEGINS TO ABSORB THE SYSTEM, ACCELERATING
FUNG-WONG NORTHEASTWARD AS IT CONTINUES TO BECOME EMBEDDED IN THE
BAROCLINIC BOUNDARY AND COMPLETE EXTRA-TROPICAL TRANSITION BY THE
END OF THE FORECAST PERIOD. CURRENTLY THE SYSTEM WILL TRACK TO THE
SOUTH OF KYUSHU AND SHIKOKU DUE TO THE PERSISTENT UPPER LEVEL JET,
SEEN IN ALL MODEL FIELDS, THAT IS SEMI-STATIONARY OVER SOUTH CENTRAL
JAPAN.  MODEL GUIDANCE CONTINUES TO BE DIVIDED IN THESE LATER TAUS
WITH THE JAPANESE MODELS DEPICTING A RECURVE TO THE EAST OF THE
RYUKYUS AND THE GFS MODELS 16W TRACKING WEST OF THE FIRST ISLAND
CHAIN. NAVGEM AND HWRF CONTINUE THE STORM ON A NORTHWARD TRAJECTORY,
UNDER THE INFLUENCE OF A VERY STRONG BUILDING STR TO THE EAST.
JTWC'S FORECAST IS MORE ALIGNED WITH THE GFS SOLUTIONS IN THE
EXTENDED FORECAST DUE TO THE MORE LIKELY SCENARIO OF THE STR TO THE
EAST OF THE SYSTEM BUILDING IN MORE SLOWLY AND NOT AS STRONG. DUE TO
FAIR INITIAL POSITION CONFIDENCE AND SIGNIFICANT DIFFERENCES IN THE
EXTENT AND SPEED OF THE RECURVE SCENARIO, THERE IS OVERALL LOW
CONFIDENCE IN THE FORECAST.//
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