WDPN31 PGTW 061500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (YINXING) WARNING NR 014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.1N 124.0E
   INITIAL INTENSITY: 100 KTS
   GEOGRAPHIC REFERENCE: 272 NM NORTHEAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: WESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 40 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON
(TY) 24W WITH AN EVIDENT AND RAGGED EYE-FEATURE THAT HAS PERSISTED
OVER THE LAST SIX HOURS. ALTHOUGH TOPS HAVE WARMED OVER THE LAST
FEW HOURS, CONVECTION HAS CONTINUED TO WRAP SYMMETRICALLY AROUND
THE LOW-LEVEL CIRCULATION CENTER (LLCC), IMPROVING THE OVERALL
STRUCTURE OF 24W, WITH AN ADDITIONAL CURVED CONVECTIVE BAND
EXTENDING EASTWARD WITHIN THE NORTHERN QUADRANT. THE WATER VAPOR
IMAGERY LOOP ALSO INDICATES SUSTAINED STRONG POLEWARD OUTFLOW,
ENHANCED BY A MID-LATITUDE JET STREAK TO THE NORTH. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE OBSERVABLE AND
AFOREMENTIONED RAGGED EYE-FEATURE INDICATED ON ANIMATED EIR
SATELLITE IMAGERY. THE INITIAL INTENSITY IS SET WITH MEDIUM
CONFIDENCE, BASED ON THE T5.5 DVORAK CURRENT INTENSITY ESTIMATES
FROM PGTW, RJTD, RCTP, AND DEMS. THE 1300Z CIMSS SATCON AND ADT
ESTIMATES RANGE FROM 95 KTS TO 115 KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE NORTH,
EXTENDING WESTWARD

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   RJTD: T5.5 - 102 KTS
   RCTP: T5.5 - 102 KTS
   KNES: T6.0 - 115 KTS
   DEMS: T5.5 - 102 KTS
   CIMSS SATCON: 95 KTS AT 1300Z
   CIMSS ADT: 115 KTS AT 061300Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 26-28 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   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 (TY) 24W (YINGXING) WILL TRACK
GENERALLY WESTWARD UNDER THE INFLUENCE OF WESTWARD EXTENDING
RIDGING FROM THE DEEP-LAYER SUBTROPICAL STEERING RIDGE TO THE NORTH
INTO TAU 72. WHILE THE SYSTEM NEARS TAU 96, A WEAKENED 24W WILL
BEGIN ITS SOUTHWESTWARD TRACK DUE TO RELATIVELY STRONG
NORTHEASTERLIES THROUGH THE TAIWAN STRAIT AND INTO THE SOUTH CHINA
SEA INTO TAU 120. REGARDING INTENSIFICATION AND WEAKENING AS THE
SYSTEM MOVES WESTWARD NEAR LUZON, ISOLATED POCKETS OF COOLER SEA
SURFACE TEMPERATURES OF LESS THAN 26 C AND INCREASING VERTICAL WIND
SHEAR (VWS) IS EXPECTED TO LIMIT INTENSIFICATION OVER THE NEXT 12
HOURS. AFTER TAU 12, ISOLATED, YET PERSISTENT COOLER POCKETS OF SEA 
SURFACE TEMPERATURES AND MODERATE VERTICAL WIND SHEAR THROUGHOUT THE 
SOUTH CHINA SEA WILL BEGIN TO WEAKEN TY YINGXING INTO TAU 72. AFTER 
TAU 72, A COLD SURGE EVENT PROGRESSING TO THE SOUTHWEST THROUGH THE 
TAIWAN STRAIT WILL GRADUALLY ERODE 24W WITH THE ADDITIONAL LIMITING 
ENVIRONMENTAL FACTOR OF DRY AIR IN THE SYSTEMS CORE STRUCTURE, 
WEAKENING THE INTENSITY TO 45 KTS BY TAU 120.

MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN VERY
TIGHT AGREEMENT WITH A CROSS-TRACK SPREAD OF 54 NM BY TAU 72.
FOLLOWING TAU 72, THE MODELS BEGIN TO DIVERGE SIGNIFICANTLY TO 343
NM NEAR TAU 120 AS WEAKENING OF THE SYSTEM VARIES BETWEEN MODEL
GUIDANCE WITH INFLUENCES FROM THE EXPECTED COLD SURGE EVENT WEST OF
LUZON, LENDING HIGH CONFIDENCE TO THE TRACK CONFIDENCE INTO TAU 72. IN 
REGARD TO THE JTWC MULTI-MODEL INTENSITY GUIDANCE, GFS CONTINUES TO 
SHOW A QUICKER WEAKENING PHASE BEGINNING AT TAU 0, WHILE THE JTWC 
INTENSITY FORECAST REMAINS CONSISTENT TO THE MULTI-MODEL CONSENSUS OF 
A GRADUAL WEAKENING TREND IN INTENSITY FOR 24W BEGINNING AT TAU 18, 
AND CONTINUING THROUGH THE REMAINDER OF THE FORECAST PERIOD, LENDING 
MEDIUM CONFIDENCE IN THE INTENSITY FORECAST THROUGH TAU 120.

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