Tropical Storm SURIGAE Advisory 4月19日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 02W (SURIGAE) WARNING NR 022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 02W (SURIGAE), LOCATED APPROXIMATELY 322 NM EAST OF
MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 05 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY
SHOWS A SYSTEM THAT REMAINS INTENSE, WITH A WARM CENTER AND
CONVECTIVE TOPS OVER A LARGE SYMMETRICAL CENTRAL DENSE OVERCAST
MAINTAINING A PINHOLE 8-NM EYE. THE INITIAL POSITION IS PLACED WITH
HIGH CONFIDENCE BASED ON THE EYE FEATURE IN THE EIR LOOP AND
EXTRAPOLATION FROM AN 181729Z AMSR2 89GHZ IMAGE. THE INITIAL
INTENSITY OF 120KTS IS BASED BETWEEN MULTIPLE AGENCY DVORAK FINAL-T
ESTIMATES RANGING FROM T6.0/115KTS (PGTW, RCTP) TO T6.5/127KTS
(KNES, RJTD). ANALYSIS INDICATES A SLIGHTLY UNFAVORABLE ENVIRONMENT
WITH THE LOW (5-10KT) VERTICAL WIND SHEAR (VWS) AND WARM (29-30C)
SEA SURFACE TEMPERATURES (SSTS) IN THE PHILIPPINE SEA OFFSET BY
DIMINISHING POLEWARD OUTFLOW CURRENTLY BEING SUPPRESSED BY THE
MIDLATITUDE TROUGH MIGRATING TO THE NORTH. THE CYCLONE IS TRACKING
ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE
EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 02W WILL CONTINUE TRACKING NORTH-NORTHWEST AS THE STEERING
STR ELONGATES MERIDIONALLY THROUGH TAU 48, THEREAFTER, THE SYSTEM
WILL NEAR THE APEX OF THE STR AXIS BY TAU 72. THE DIMINISHING
OUTFLOW OFFSETTING THE LOW VWS AND WARM SSTS WILL PRIMARILY BE
RESPONSIBLE FOR ITS GRADUAL WEAKENING, DOWN TO 95KTS BY TAU 72.
NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH A GRADUAL, AND EVEN
CROSS-TRACK SPREAD TO 156NM BY TAU 72. THE GFS ENSEMBLE IS THE FAR
RIGHT OUTLIER, LENDING FAIR CONFIDENCE IN THIS PORTION OF THE JTWC
FORECAST TRACK, WHICH IS LAID CLOSE TO AND SLIGHTLY LEFT OF THE
MULTI-MODEL CONSENSUS.
   C. AFTER TAU 72, TY SURIGAE WILL CREST THE STR AXIS, RECURVE AND
ACCELERATE NORTHEASTWARD. AS SURIGAE MOVES TO HIGHER LATITUDES, THE
INCREASING VWS AND MUCH COOLER SSTS (24-25C) WILL BEGIN TO RAPIDLY
DECAY THE INTENSITY TO 65KTS BY TAU 72. SIMULTANEOUSLY, THE SYSTEM
WILL BEGIN EXTRATROPICAL TRANSITION. THE NUMERICAL MODELS REMAIN
TIGHT AND SPREAD OUT TO 200NM BY TAU 96, LENDING FAIR CONFIDENCE
DURING THIS TIME. HOWEVER, BEYOND TAU 96 ALONG TRACK ERRORS
INCREASE, AS THE SYSTEM BEGINS THE EXTRATROPICAL TRANSITION, LENDING
LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.//
NNNN
NNNN