WDPN31 PGTW 060300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (YINXING) WARNING NR 012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.1N 124.7E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 299 NM NORTHEAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 42 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE
SYSTEM HAS MOSTLY MAINTAINED ITS STRUCTURE AND CONVECTIVE SIGNATURE 
OVER THE PAST SIX HOURS AS IT SLOWED DOWN ON ITS FORWARD MOTION IN THE 
PHILIPPINE SEA. THE HIGHLY SYMMETRICAL CENTRAL COLD COVER REMAINS
COMPACT AND DEEP WITH OVERSHOOTING CLOUD TOPS AND A PINHOLE FORMATIVE 
EYE AS IT GOES THROUGH ITS DIURNAL MINIMUM CYCLE. THE EIR LOOP ALSO 
SHOWS A STEADFAST VIGOROUS POLEWARD OUTFLOW. THE INITIAL POSITION, 
ADJUSTED FOR A SLIGHT FORWARD TILT, IS PLACED WITH HIGH CONFIDENCE 
BASED ON THE TIGHT CLUSTER OF WARM PIXELS OVER THE FORMATIVE EYE. THE 
INITIAL INTENSITY IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON 
IDENTICAL AND NEARLY CONCENTRIC DVORAK ESTIMATES FROM PGTW, RJTD, AND 
RCTP, AND REFLECTS THE SUSTAINED 6-HR WRAP AND EIR CONVECTIVE 
SIGNATURE. ANALYSIS INDICATES TY 24W IS APPROACHING THE COL AREA 
BETWEEN THE STEERING RIDGE TO THE NORTHEAST AND THE STR TO THE WEST; 
HOWEVER, THE ENVIRONMENT REMAINS HIGHLY FAVORABLE WITH LOW VWS, WARM 
ALONG-TRACK SSTS, AND ROBUST VENTILATION.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO
THE NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T5.0 - 90 KTS
   CIMSS ADT: 61 KTS AT 052030Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 05-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TYPHOON YINXING WILL CONTINUE ON ITS CURRENT
SLOW NORTHWESTWARD TRACK UP TO TAU 24; AFTERWARD, A SECONDARY STR
BUILDING IN FROM THE WEST NEAR HAINAN WILL ASSUME STEERING AND
DRIVE THE CYCLONE ON A MORE WESTWARD TRAJECTORY THROUGH THE LUZON
STRAIT AND INTO THE SOUTH CHINA SEA (SCS). THE HIGHLY FAVORABLE
ENVIRONMENT WILL PROMOTE INTENSIFICATION TO A PEAK OF 105KTS BY TAU
24 FUELED BY INCREASED POLEWARD OUTFLOW ENHANCED BY THE SOUTHWESTERLY 
JETS JUST TO THE NORTH AND AHEAD OF A TRANSITING MID-LATITUDE TROUGH. 
AFTERWARD, THE RELATIVE VWS WILL INCREASE, SST AND OHC VALUES DECREASE 
IN THE WAKE OF A PREVIOUS CYCLONE (23W), INTERACTION WITH LUZON, THEN 
THE DRIFT INTO A COLD NORTHEASTERLY SURGE IN THE SCS WILL SLOWLY THEN 
RAPIDLY ERODE THE SYSTEM DOWN TO 45KTS BY TAU 120. MODEL DISCUSSION: 
NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT WITH AN EVEN ACROSS-TRACK 
SPREAD TO A MERE 78NM BY TAU 72; AFTERWARD, THE MODELS SPREAD OUT TO 
285NM AT TAU 120, LENDING HIGH CONFIDENCE UP TO TAU 72, THEN LOW 
CONFIDENCE AFTERWARD, TO THE JTWC TRACK FORECAST. THERE IS MEDIUM 
CONFIDENCE TO THE INTENSITY FORECAST UP TO TAU 72, THEN LOW CONFIDENCE 
AFTERWARD.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: HIGH
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: HIGH//
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