Tropical Storm FUNG-WONG Advisory Sat Sep 20

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (FUNG-WONG) WARNING
NR 08//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 16W (FUNG-WONG), LOCATED APPROXIMATELY 247 NM
NORTH OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 13
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) SHOWS THE LOW LEVEL CIRCULATION CENTER (LLCC) HAS
BECOME DISORGANIZED AS THE SYSTEM CROSSED THE NORTHERN COAST OF
LUZON WHILE DEEP CONVECTION HAS WANED. A 190631Z SSMI MICROWAVE
IMAGE ADDITIONALLY REVEALS THE BULK OF THE DEEP CONVECTION HAS
BECOME CONTAINED TO THE SOUTHERN PERIPHERIES AS THE LLCC HAS BECOME
LESS DEFINED. THE CURRENT POSITION IS BASED ON THE MSI LOOP WITH
FAIR CONFIDENCE. THE INITIAL INTENSITY REMAINS AT 40 KTS BASED ON
DVORAK INTENSITY ESTIMATES THAT RANGE FROM 35 TO 45 KNOTS WHILE A
190231Z PARTIAL ASCAT PASS 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. THE INTENSITY FORECAST HAS BEEN DECREASED DUE TO INCREASED
LAND INTERACTION.
   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 OF 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. LANDFALL INTO SOUTHERN TAIWAN IS EXPECTED NEAR TAU 36 AND
WEAKENING IS FORECAST AS THE SYSTEM DRAGS ACROSS THE MOUNTAINOUS
TERRAIN OF TAIWAN. MODEL GUIDANCE IS GOOD AGREEMENT THROUGH THIS
PORTION OF THE FORECAST WITH ALL MODELS INDICATING THE NORTHWARD
TURN IN THE NEXT 24 HOURS AND LAND FALL INTO TAIWAN.
   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. ECMWF, JGSM, AND THE JAPANESE ENSEMBLE KEEP 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 96, THE
SYSTEM IS EXPECTED TO BECOME EMBEDDED IN THE MID-LATITUDE WESTERLIES
WHICH WILL INDUCE EXTRA-TROPICAL TRANSITION AND ACCELERATE THE
SYSTEM TO THE NORTHEAST. 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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