WDPN31 PGTW 031500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (KOINU) WARNING NR 017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.7N 124.6E
   INITIAL INTENSITY: 95 KTS
   GEOGRAPHIC REFERENCE: 266 NM SOUTHEAST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 33 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON
(TY) 14W FIGHTING TO MAINTAIN INTENSITY IN A MARGINALLY FAVORABLE
ENVIRONMENT OVER THE PAST SIX HOURS. STRONG EQUATORWARD OUTFLOW
ALOFT IS OBSERVED, AS EVIDENCED BY THIN DRIFTING FILAMENTS OF
CIRRUS CLOUDS.  DEEP CONVECTION PERSISTS, MOST PROMINENTLY IN THE
SOUTHERN SEMICIRCLE, COMPLETELY OBSCURING THE EYE ON EIR IMAGERY. A
030945Z REM3 SYNTHETIC APERTURE RADAR (SAR) IMAGE, HOWEVER,
DEPICTS AN ASYMMETRICAL, RAGGED EYE (20 X 15 NM) EMBEDDED UNDER
THE CONVECTIVE CANOPY. VERTICAL WIND SHEAR (VWS) AND DRY AIR
ENTRAINMENT CONTINUE TO RESTRAIN THE SYSTEM FROM INTENSIFYING
DESPITE THE WARM SEA SURFACE TEMPERATURES AND EXCEPTIONAL OUTFLOW.
THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A
031200Z HIMAWARI 9 EIR IMAGE AND EXTRAPOLATION OF THE PREVIOUSLY
MENTIONED SAR IMAGE. THE INITIAL INTENSITY OF 95 KTS IS ASSESSED
WITH MEDIUM CONFIDENCE BASED ON FALLING PGTW, RJTD, AND KNES DVORAK
SUBJECTIVE INTENSITY ESTIMATES AND CIMSS OBJECTIVE INTENSITY
ESTIMATES, LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE EAST AND NORTHEAST WITH A BREAK TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   RJTD: T5.5 - 102 KTS
   KNES: T5.5 - 102 KTS
   CIMSS ADT: 102 KTS AT 030830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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) 14W IS FORECAST TO TRACK
WEST-NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF RIDGING TO
THE NORTHEAST AND NORTHWEST THROUGH TAU 12. THE STEERING INFLUENCE
OF THE RIDGING TO THE NORTHWEST WILL PROVIDE FORCING CONDUCIVE OF A
WESTWARD TRACK AFTER TAU 12 THROUGH TAU 120. TY 14W IS FORECAST TO
WEAKEN STEADILY THROUGH THE FORECAST INTERVAL DUE TO THE PERSISTENT 
VWS AND DRY AIR ENTRAINMENT AS IT APPROACHES AND TRACKS OVER SOUTHERN 
TAIWAN (AROUND TAU 36) WITH FURTHER WEAKENING AS IT TRACKS OVER THE 
SOUTH CHINA SEA, TAIWAN STRAIT REGION (TAU 48 TO TAU 96).

MODEL DISCUSSION: GLOBAL NUMERICAL MODEL GUIDANCE IS IN GOOD
AGREEMENT THAT TY 14W WILL TRACK WEST-NORTHWESTWARD TO WESTWARD
THROUGH TAU 72, GRADUALLY WEAKENING ALONG TRACK. THE TAU 72
CROSS-TRACK SPREAD OF 113NM, AND ALONG-TRACK SPREAD OF 172NM HAS
SLIGHTLY INCREASED SINCE WARNING NUMBER 016, LENDING TO AN OVERALL
0 TO 72 HOUR FORECAST CONFIDENCE FOR BOTH TRACK AND INTENSITY OF
MEDIUM. THE WESTWARD TRACK CONTINUES THROUGH TAU 96, BUT THEN
OFFERS A MYRIAD OF SOLUTIONS FROM TAU 96 TO TAU 120. TRACK
SOLUTIONS DURING THIS PERIOD INCLUDE: A RECURVE TO THE NORTHEAST 
(ONLY MOGREPS), A RECIPROCAL TRACK (ONLY JGSM), A SOUTHERN CHINA 
LANDFALL EVENT, OR A TRACK INTO THE SOUTH CHINA SEA.  DUE TO THE LARGE
DISPERSION OF SOLUTIONS OVER THIS INTERVAL, THE FORECAST CONFIDENCE
OF BOTH TRACK AND INTENSITY AFTER TAU 72 IS LOW.

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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