Tropical Storm FUNG-WONG Advisory Fri Sep 19

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (FUNG-WONG) WARNING
NR 09//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 16W (FUNG-WONG), LOCATED APPROXIMATELY 254 NM
NORTH-NORTHWEST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 13
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY (EIR) SHOWS FLARING CONVECTION ALONG THE SOUTHERN PERIPHERY
OF THE LOW LEVEL CIRCULATION CENTER (LLCC) THAT CONTINUES TO
STRUGGLE AFTER CROSSING THE NORTHERN COAST OF LUZON. A 191000Z SSMIS
MICROWAVE 37 GHZ IMAGE ADDITIONALLY REVEALS THE BULK OF THE DEEP
CONVECTION REMAINS ALONG THE SOUTHERN PERIPHERIES OF THE LLCC WHICH
HAS BECOME LESS DEFINED. THE CURRENT POSITION IS BASED ON THE EIR
LOOP ALONG WITH THE SSMIS IMAGE WITH FAIR CONFIDENCE. THE INITIAL
INTENSITY REMAINS AT 40 KTS BASED ON DVORAK INTENSITY ESTIMATES THAT
RANGE FROM 35 TO 45 KNOTS AND PERSISTENCE FROM A PREVIOUS ASCAT PASS
THAT INDICATED 40 KNOTS. UPPER-LEVEL ANALYSIS INDICATES A MARGINALLY
CONDUCIVE ENVIRONMENT AS MODERATE (15 TO 20 KNOTS) NORTHERLY
VERTICAL WIND SHEAR (VWS) IS BEING OFFSET BY STRONG EQUATORWARD
OUTFLOW. TS FUNG-WONG IS CURRENTLY TRACKING ALONG THE SOUTHWESTERN
PERIPHERY OF THE SUBTROPICAL RIDGE (STR) THAT IS POSITIONED TO THE
NORTHEAST OF THE SYSTEM.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING.
   B. TS 16W IS EXPECTED TO SLOW DOWN AND TURN NORTH THROUGH THE
NEXT DAY AS THE CURRENT STEERING STR RE-ORIENTS AND ANOTHER STR
CURRENTLY OVER SOUTHEASTERN CHINA RETROGRADES TO THE WEST AND
WEAKENS. TS 15W WILL THEN CONTINUE NORTH ALONG THE WESTERN
PERIPHERY OF THE EASTERN STR. THE SYSTEM IS EXPECTED TO SLIGHTLY
INTENSIFY AS IT PROCEEDS ACROSS THE LUZON STRAIT AS WARM SEA SURFACE
TEMPERATURES AND A MORE FAVORABLE UPPER LEVEL ENVIRONMENT IS
FORECAST. THE SYSTEM IS NOW EXPECTED TO PASS ALONG THE WESTERN COAST
OF TAIWAN NEAR TAU 36 AND WEAKEN AS THE MOUNTAINOUS TERRAIN OF
TAIWAN IMPACTS THE LOW LEVEL INFLOW. MODEL GUIDANCE IS GOOD
AGREEMENT THROUGH THIS PORTION OF THE FORECAST WITH ALL MODELS
INDICATING THE NORTHWARD TURN IN THE NEXT 12 HOURS.
   C. IN THE EXTENDED TAUS, THE SYSTEM IS EXPECTED TO CONTINUE TO
PROCEED POLEWARD ALONG THE WESTERN PERIPHERY OF THE STR. MODEL
GUIDANCE IS VARYING IN THE EXTENT OF THE STR IN THIS PORTION OF THE
FORECAST PERIOD. JGSM, AND THE JAPANESE ENSEMBLE REMAIN THE RIGHT
MOST OUTLIERS KEEPING THE STR MORE POLEWARD ORIENTED ALLOWING THE
SYSTEM TO PROCEED MORE NORTH. GFDN, NAVGEM, GFS, THE GFS ENSEMBLE
MEAN, AND COAMPS-TC INDICATE A MORE NORTHWEST TO SOUTHEAST STR
ORIENTED THAT AMPLIFIES DRIVING THE SYSTEM MORE NORTHWEST TOWARDS
MAINLAND CHINA. AFTER TAU 72 AND LAND FALL INTO CHINA, THE SYSTEM IS
EXPECTED TO BECOME EMBEDDED IN THE MID-LATITUDE WESTERLIES WHICH
WILL INDUCE EXTRA-TROPICAL TRANSITION (ETT) AND ACCELERATE THE
SYSTEM TO THE NORTHEAST, COMPLETING ETT BY THE END OF THE FORECAST.
THE FORECAST TRACK IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS
ALONG WITH THE BULK OF THE MODEL GUIDANCE. OVERALL, THERE IS LOW
CONFIDENCE IN THE FORECAST TRACK DUE THE VARYING EXTENT OF STR
DEPICTED IN THE MODEL TRACKERS.//
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