Tropical Storm KIROGI Advisory sáb, 18-11

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 31W (THIRTYONE)
WARNING NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 31W (THIRTYONE), LOCATED APPROXIMATELY 50
NM NORTHWEST OF PUERTO PRINCESA, PALAWAN, PHILIPPINES, HAS TRACKED
NORTHWESTWARD AT 16 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED
INFRARED (EIR) SATELLITE IMAGERY SHOWS POORLY ORGANIZED, FRAGMENTED,
AND SHALLOW, ALBEIT FORMATIVE CONVECTIVE BANDS LOOSELY FEEDING INTO A
WEAK AND OBSCURED LOW LEVEL CIRCULATION. THE INITIAL POSITION IS
BASED ON THE EIR ANIMATION AND LINED UP WITH A LOW REFLECTIVITY NOTCH
FEATURE IN THE 171028Z SSMIS MICROWAVE PASS WITH FAIR CONFIDENCE. THE
INITIAL INTENSITY OF 25 KNOTS IS BASED ON AN OVERALL ASSESSMENT OF
AGENCY AND OBJECTIVE DVORAK ESTIMATES. UPPER LEVEL ANALYSIS INDICATES
TD 31W IS IN AN AREA OF MODERATE (15-20 KNOT) EASTERLY VERTICAL WIND
SHEAR THAT IS PARTLY OFFSET BY ITS STORM MOTION THAT IS IN-PHASE WITH
THE VWS VECTOR, AND STRONG WESTWARD OUTFLOW. ALONG-TRACK SEA SURFACE
TEMPERATURES IN THE SOUTH CHINA SEA (SCS) ARE ALSO CONDUCIVE AT 30
CELSIUS. THESE FAVORABLE DYNAMICS ARE TEMPERED, HOWEVER, BY THE COOL
DRY NORTHEASTERLY MONSOON WINDS IN THE SCS. THE CYCLONE IS TRACKING
ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE
NORTH.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING MESSAGE AND SETS THE
FORECAST PHILOSOPHY FOR THIS SYSTEM.
   B. TD 31W IS EXPECTED TO TRACK WEST-NORTHWESTWARD THEN WESTWARD
THROUGH ITS LIFESPAN, MAKING LANDFALL OVER SOUTHERN VIETNAM NEAR TAU
42. OVERALL FAVORABLE CONDITIONS IN THE SCS, HINDERED BY THE
NORTHEAST MONSOON, WILL PROMOTE MINIMAL INTENSIFICATION, PEAKING AT
45 KNOTS PRIOR TO LANDFALL. AFTERWARD, INTERACTION WITH THE RUGGED
TERRAIN OF THE INDOCHINA PENINSULA WILL RAPIDLY ERODE THE SYSTEM,
LEADING TO DISSIPATION BY TAU 72 OVER EASTERN THAILAND. DYNAMIC MODEL
GUIDANCE IS IN UNUSUALLY GOOD AGREEMENT FOR A DEVELOPING CYCLONE;
HOWEVER, GIVEN THE FORMATIVE NATURE AND ERRATIC STORM MOTION, THERE
IS LOW CONFIDENCE IN THE FIRST JTWC TRACK FORECAST ON TD 31W.//
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