WDPN32 PGTW 120900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (MUIFA) WARNING NR 024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 24.8N 124.1E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 225 NM WEST-SOUTHWEST OF KADENA AB,
OKINAWA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 36 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A MEDIUM-SIZED
TYPHOON WITH A SYMMETRICAL DEEP CENTRAL CONVECTION THAT HAS JUST
COMPLETED AN EYEWALL REPLACEMENT CYCLE AS EVIDENCED BY AN EYE THAT
HAS SHRUNK DOWN TO 18NM IN DIAMETER FROM 60NM 6HRS PRIOR. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE IN
THE MSI LOOP THAT WAS CONCENTRIC WITH A WELL-DEFINED CIRCULATION
FEATURE IN THE COMPOSITE RADAR LOOP FROM JMA. THE INITIAL INTENSITY IS 
ALSO PLACED WITH HIGH CONFIDENCE BASED ON EQUIVALENT AGENCY DVORAK
ESTIMATES AND REFLECTS THE SLIGHT 6-HR DEGRADATION. ANALYSIS
INDICATES A MARGINAL ENVIRONMENT WITH MEDIUM RADIAL OUTFLOW AND
LIGHT VWS OFFSET BY COOLING SST DUE TO UPWELLING BROUGHT ON BY THE
CURRENT SLOW STORM MOTION.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

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


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 99 KTS AT 120456Z
   CIMSS ADT: 97 KTS AT 120530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: A MIDLATITUDE SHORTWAVE TROUGH EXITING CHINA
VIA THE YELLOW SEA HAS WEAKENED THE STEERING STR AND ALLOWED THE
SYSTEM TO TRACK MORE NORTHWARD. BEHIND THE TROUGH, A SECONDARY STR
TO THE NORTHWEST IS COMPETING FOR STEERING CAUSING THE SLOW STORM
MOTION. AFTER TAU 24, THE STR TO THE NORTHEAST WILL BUILD ANEW AND
REGAIN FULL STEERING AND ACCELERATE TY 14W NORTH-NORTHWESTWARD. THE
MARGINAL ENVIRONMENT WILL VERY SLOWLY WEAKEN THE SYSTEM DOWN TO
70KTS BY TAU 48. AFTERWARD, COOLING SST IN THE EAST CHINA SEA,
INCREASING VWS, AND LANDFALL INTO NORTHEAST CHINA VIA SHANGHAI WILL
RAPIDLY ERODE THE SYSTEM AND BY TAU 120 WILL DISSIPATE OVER THE
SHANDONG BANDAO PENINSULA.

MODEL DISCUSSION: THE MAIN PACK OF NUMERICAL MODELS ARE IN TIGHT
AGREEMENT EVENLY SPREADING OUT TO 135NM BY TAU 72 THEN TO 400NM+ BY
TAU 120 AS THE MODELS LOSE A DISSIPATING VORTEX. NVGM AND JGSM ARE
THE LEFT OUTLIERS OUTSIDE THE MAIN PACK. IN VIEW OF THIS, THERE IS
MEDIUM CONFIDENCE IN THE JTWC TRACK AND INTENSITY FORECASTS, LAID
CLOSE TO THE MODEL TRACK AND INTENSITY CONSENSUS, UP TO TAU 72 THEN
LOW CONFIDENCE AFTERWARD.


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