Tropical Storm FUNG-WONG Advisory mié, 17-09

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 16W (SIXTEEN)
WARNING NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 16W (SIXTEEN), LOCATED APPROXIMATELY 581
NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 19
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS A CENTRAL DENSE OVERCAST FEATURE WITH
FORMATIVE BANDING ON THE NORTHERN AND SOUTHERN PERIPHERY WRAPPING
INTO A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC). A 171054Z
SSMIS MICROWAVE IMAGE ALSO REVEALS INCREASED CENTRAL DEEP CONVECTION
OBSCURING THE LLCC WITH BROKEN CONVECTIVE BANDS WRAPPING TOWARDS THE
CENTER. THE CURRENT POSITION IS BASED ON THE EIR AND AFOREMENTIONED
MICROWAVE IMAGE WITH LOW CONFIDENCE. THE INITIAL INTENSITY IS
ASSESSED AT 30 KNOTS BASED ON AN OVERALL ASSESSMENT OF DVORAK
INTENSITY ESTIMATES FROM ALL REPORTING AGENCIES AS WELL AS THE
CURRENT STRUCTURE. UPPER-LEVEL ANALYSIS INDICATES A POINT-SOURCE IS
LOCATED OVER THE SYSTEM SUSTAINING THE INCREASED CONVECTION. WATER
VAPOR IMAGERY SHOWS ENHANCED POLEWARD OUTFLOW TAPPING INTO A TUTT
CELL LOCATED TO THE NORTHEAST OF THE SYSTEM. IN ADDITION TO
FAVORABLE VERTICAL WIND SHEAR ENVIRONMENT, WARM SEA SURFACE
TEMPERATURES (SSTS) IN THE PHILIPPINES SEA ARE CONDUCIVE FOR FURTHER
DEVELOPMENT. TD 16W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF
A SUBTROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST
PHILOSOPHY.
   B. TD 16W IS FORECAST TO MAINTAIN A WEST-NORTHWESTWARD TRACK
THROUGH TAU 36, BUT WILL BEGIN TURNING NORTHWARD BEYOND THIS POINT
AS THE STR BEGINS TO RE-ALIGN UNDER THE INFLUENCE OF A TRANSITORY
MID-LATITUDE LOW LOCATED OVER NORTHERN JAPAN. BY TAU 48, TD 16W WILL
CREST THE RIDGE AND BEGIN TO TURN TO THE NORTH-NORTHEAST. TD 16W IS
EXPECTED TO UNDERGO RAPID INTENSIFICATION OVER THE NEXT 36 TO 48
HOURS AS THE SSTS REMAIN VERY FAVORABLE AND VIGOROUS UPPER-LEVEL
SUPPORT ALONG THE FORECAST TRACK. BY TAU 72, TD 16W IS EXPECTED TO
BEGIN EXTRA-TROPICAL TRANSITION (ETT) AS IT INTERACTS WITH THE MID-
LATITUDE WESTERLIES. FAVORABLE UPPER-LEVEL CONDITIONS ARE EXPECTED
TO PERSIST, ALLOWING TD 16W TO FURTHER INTENSIFY AND LEADING TO A
PEAK INTENSITY AT 90 KNOTS BY TAU 72.
   C. IN THE EXTENDED TAUS, INCREASING INTERACTION WITH THE
AFOREMENTIONED MID-LATITUDE WESTERLIES WILL SLOWLY WEAKEN THE
STRUCTURE OF TD 16W. AROUND TAU 96, TD 16W WILL ACCELERATE
NORTHEASTWARD AS IT BECOMES EMBEDDED IN THE BAROCLINIC BOUNDARY. AND
WILL COMPLETE ETT BY THE END OF THE FORECAST PERIOD AS A TYPHOON
STRENGTH COLD-CORE LOW. AVAILABLE MODEL GUIDANCE IS IN GOOD
AGREEMENT IN THE NEAR TERM, HOWEVER INDICATES VARIATIONS AT THE RE-
CURVE POINT SHOWING A 150 NM SPREAD AT TAU 48 WITH GFDN AND JAPANESE
ENSEMBLE (JENS) MODELS TAKING A SHARPER EASTWARD RECURVE. DUE TO LOW
INITIAL POSITION CONFIDENCE AND SOME SLIGHT DIFFERENCES IN THE
EXTENT AND SPEED OF THE RECURVE SCENARIO, THERE IS OVERALL LOW
CONFIDENCE IN THE FORECAST TRACK WHICH IS POSITIONED SLIGHTLY
WESTWARD OF MULTI-MODEL CONSENSUS TO OFFSET THE GFDN AND JENS
SOLUTIONS.//
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