Tropical Storm GONI Advisory Sun Nov 01

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 22W (GONI) WARNING
NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 22W (GONI), LOCATED APPROXIMATELY 106 NM SOUTHEAST
OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS
THE SYSTEM HAS SIGNIFICANTLY ERODED AS IT DRAGGED ACROSS THE
SOUTHEASTERN ISLANDS OF LUZON. CENTRAL CONVECTIVE TOPS HAVE GREATLY
WARMED AND FEEDER BANDS HAVE BECOME FRAGMENTED. THE INITIAL POSITION
IS PLACED WITH FAIR CONFIDENCE BASED THE MSI AND COMPOSITE RADAR
LOOPS. THE INITIAL INTENSITY OF 75KTS IS DEDUCED FROM NEARBY WIND
AND MEAN SEA LEVEL PRESSURE OBSERVATIONS. UPPER LEVEL DYNAMICS ARE
MARGINAL WITH MODERATE (20-25KT) VERTICAL WIND SHEAR (VWS) PARTIALLY
OFFSET BY GOOD RADIAL OUTFLOW.THE CYCLONE IS TRACKING ALONG THE
SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE
NORTHWEST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY 22W WILL TRACK MORE WEST-NORTHWESTWARD JUST TO THE SOUTH OF
MANILA, AS THE STR RECEDES WESTWARD, AND EXIT INTO THE  SOUTH CHINA
SEA (SCS) JUST BEFORE TAU 12. AFTER TAU 24, THE STR  WILL REBUILD
AND DRIVE THE SYSTEM ON A WESTWARD TO WEST-SOUTHWESTWARD TRAJECTORY.
THE MARGINAL UPPER LEVEL DYNAMICS COMBINED WITH FRICTIONAL EFFECTS
FROM THE ISLANDS WILL CONTINUE TO WEAKEN TY 22W TO 65KTS BY TAU 12.
AFTERWARD, THE ADDITION OF COOLING SEA SURFACE TEMPERATURES (SST) IN
THE SCS WILL AID IN WEAKENING THE SYSTEM TO 50KTS BY TAU 36. AFTER
TAU 36, THE ENVIRONMENT WILL BE IN A QUASI-EQUILIBRIUM AS ROBUST
RADIAL OUTFLOW IS OFFSET BY MODERATE VWS AND COOL SST, SUSTAINING
THE INTENSITY AT 50KTS UP TO TAU 72. NUMERICAL MODELS ARE IN FAIRLY
TIGHT AGREEMENT WITH GRADUAL, EVEN SPREADING TO 210NM AT TAU 72,
LENDING HIGH CONFIDENCE IN THIS PORTION OF THE JTWC TRACK FORECAST.
   C. BEYOND TAU 72, TY GONI WILL CONTINUE WEST-SOUTHWESTWARD UNDER
THE SAME STR, MAKE LANDFALL OVER SOUTHERN VIETNAM NEAR QUI NOHN
SHORTLY AFTER TAU 96. COOLING SST AND LAND INTERACTION WILL
PRIMARILY ERODE THE SYSTEM TO 25KTS BY TAU 120. NUMERICAL MODELS
CONTINUE TO DIVERGE EVENLY TO OVER 500NM BY TAU 120. IN VIEW OF
THIS, THERE IS FAIR CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC
TRACK FORECAST, WHICH IS LAID ALONG THE MULTI-MODEL CONSENSUS.//
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