WDPN32 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (MUIFA) WARNING 
NR 029//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.8N 123.9E
   INITIAL INTENSITY: 90 KTS
   GEOGRAPHIC REFERENCE: 165 NM NORTHEAST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 34 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
SPASMODIC EYE WITH WELL DEFINED, DEEP CONVECTIVE CLOUD LINES
TIGHTLY WARPING INTO THE CIRCULATION CENTER. SOLID MICROWAVE
IMAGERY REMAINS CAPRICIOUS, HOWEVER, A 130824Z SSMIS MICROWAVE
IMAGE SHOWS THAT THE EYE IS FRAGMENTING AND DEEP CONVECTION IS
BECOMING ISOLATED TO POCKETS AROUND THE LLCC, RATHER THAN OCCURRING
THROUGHOUT THE SYSTEM. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON EIR AND SSMIS IMAGERY. THE INITIAL INTENSITY OF
90 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON PGTW, RJTD AND
KNES DVORAK INTENSITY ESTIMATES RETURNING T5.0 AS WELL AS CIMSS ADT
RETURNING 92 KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.0 - 90 KTS
   RJTD: T5.0 - 90 KTS
   KNES: T5.0 - 90 KTS
   CIMSS ADT: 92 KTS AT 131130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 0-5 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TY 14W CONTINUES TRACKING NORTH-NORTHWESTWARD
UNDER THE STEERING INFLUENCE OF THE STR TO THE NORTHEAST. BY TAU 12
AS TRACK SPEEDS BEGIN TO INCREASE PAST 7 KNOTS THE SYSTEM WILL BE
IN A MARGINAL ENVIRONMENT CHARACTERIZED BY LOW VERTICAL WIND SHEAR
(5-10 KNOTS) AND GOOD OUTFLOW ALOFT STRUGGLING TO COUNTERACT
FALLING SST VALUES AND COOL OHC VALUES. BY TAU 24, NOW JUST SOUTH
OF SHANGHAI, OFF SHORE SST AND OHC VALUES QUICKLY OVERPOWER THE
OTHER ENVIRONMENTAL FACTORS AND INTENSITY IS FORECAST TO FALL
RAPIDLY. JUST AFTER TAU 24, AS THE STR CONTINUES TO FORCE THE
SYSTEM NORTH-NORTHWESTWARD, 14W MAKES LANDFALL AND INTENSITY VALUES
TAKE A NOSE DIVE. THROUGHOUT THE REMAINING FORECAST TRACK, 14W IS
STEADILY RIPPED APART BY SOUTHEASTERN CHINA, EVENTUALLY DISSIPATING
NEAR TAU 72.

MODEL DISCUSSION: WITH THE EXCEPTION OF NVGM AND COAMPS-TC (NVGM
VERSION), NUMERICAL MODELS ARE IN GOOD AGREEMENT THAT 14W WILL
CONTINUE ROUNDING THE STR, MAKING LANDFALL AFTER TAU 24 AND
CONTINUING ALONG COASTAL CHINA UNTIL DISSIPATION. FOR THIS
REASON THE JTWC FORECAST TRACK IS PLACED WITH HIGH CONFIDENCE. 
RELIABLE MODEL INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT THAT 14W 
HAS STARTED ITS DOWNWARD INTENSITY TREND, SHOWING THAT THROUGH TAU 12 
THE SYSTEM WILL GRADUALLY WEAKEN UNTIL LANDFALL AFTER WHICH A SHARP 
DECLINE THROUGH THE FORECAST PERIOD. FOR THIS REASON THE JTWC 
FORECAST INTENSITY IS PLACED WITH HIGH CONFIDENCE. 

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