Tropical Storm MEKKHALA Advisory Fri Jan 16

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 01W (MEKKHALA) WARNING
NR 12//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 01W (MEKKHALA), LOCATED APPROXIMATELY 371 NM
NORTHWEST OF KOROR, PALAU, HAS TRACKED WESTWARD AT 14 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
DEPICTS A PARTIALLY-EXPOSED, BUT TIGHTLY WRAPPED LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH IMPROVED DEEP CONVECTIVE BANDING OVER
THE WESTERN SEMI-CIRCLE. A 160336Z GCOM MICROWAVE IMAGE SHOWED A
WELL-DEFINED LLCC WITH CONVECTIVE BANDING ALONG THE WESTERN AND
NORTHERN PERIPHERY. THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION
BASED UPON THE MICROWAVE PASS AND THE MSI ANIMATION. THE CURRENT
INTENSITY REMAINS AT 40 KNOTS AS DVORAK INTENSITY ESTIMATES RANGE
FROM 35 TO 45 KNOTS. UPPER-LEVEL ANALYSIS INDICATES A CONTINUED
MARGINAL ENVIRONMENT AS MODERATE EASTERLY VERTICAL WIND SHEAR (15-20
KNOTS) CONTINUES TO OFFSET DIVERGENT POLEWARD OUTFLOW. TS MEKKHALA
IS CURRENTLY TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE
LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR) TO THE NORTH OF THE SYSTEM.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS 01W WILL CONTINUE TO TRACK WESTWARD TO WEST-NORTHWESTWARD
UNDER THE INFLUENCE OF THE STR THROUGH TAU 72 AND WILL MAKE LANDFALL
IN THE CENTRAL PHILIPPINES JUST AFTER TAU 24. TS MEKKHALA IS
FORECAST TO SLOWLY INTENSIFY PRIOR TO MAKING LANDFALL DUE TO STRONG
DIVERGENCE ALOFT AND FAVORABLE SEA SURFACE TEMPERATURES. AFTER
LANDFALL, THE SYSTEM IS EXPECTED TO WEAKEN AS LAND INTERACTION,
INCREASED VWS, AND INTERACTION WITH THE NORTHEAST SURGE EVENTUALLY
LEAD TO DISSIPATION WITH THE REMNANTS EMERGING IN THE SOUTH CHINA
SEA. NUMERIC MODEL GUIDANCE REMAINS WIDELY SPREAD AFTER LANDFALL AS
MOST OF THE TRACKERS LOSE THE VORTEX OF THE SYSTEM AND CONTINUE TO
ERRONEOUSLY JUMP INTO ANOTHER VORTICITY MAXIMUM IN THE WESTERLY
FLOW. DUE TO THIS, OVERALL LOW CONFIDENCE REMAINS IN THE FORECAST.//
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