WDPN31 PGTW 250900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (NOUL) WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.3N 116.6E
   INITIAL INTENSITY: 75 KTS
   GEOGRAPHIC REFERENCE: 147 NM EAST OF HONG KONG
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A DEVELOPING
EYE, WHICH REMAINS RAGGED AND CLOUD-FILLED. DEEP CONVECTION IS
DEVELOPING ALONG THE SOUTHERN FLANK OF THE NASCENT EYE FEATURE, BUT
STRUGGLING TO WRAP TO THE UPSHEAR SIDE OF THE EYE. CIMSS DEEP-LAYER
SHEAR ANALYSIS SUGGESTS THAT DEEP-LAYER SHEAR REMAINS LIGHT FROM THE 
NORTHEAST. HOWEVER, MODEL-BASED SOUNDINGS AND LAYER ANALYSIS SUGGESTS 
SOME HIGHER VALUES IN THE MID-LEVELS, WHICH ARE MOST LIKELY 
INHIBITING THE DEVELOPMENT OF CONVECTION IN THE NORTHEASTERN SECTOR. 
REGARDLESS, THE SYSTEM IS STEADILY IMPROVING AS IT APPROACHES THE 
COAST OF SOUTHEASTERN CHINA. ANIMATED RADAR DATA DEPICTS A WELL-
DEFINED LOWER-LEVEL EYE FEATURE, WITH AN EYE DIAMETER OF 
APPROXIMATELY 25NM AND WELL-DEFINED SPIRAL RAINBANDS WRAPPING INTO 
THE EYEWALL. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE 
BASED ON ANALYSIS OF THE RADAR DATA. THE INITIAL INTENSITY IS 
ASSESSED WITH MEDIUM CONFIDENCE, HEDGED TOWARDS THE KNES T4.5 
ESTIMATE BASED ON A SUBJECTIVE ANALYSIS OF THE SYSTEMS APPEARANCE. 
CIMSS ADT AND AIDT HAVE YET TO TRIGGER AN EYE PATTERN ALGORITHM, 
RESULTING IN AN UNDERESTIMATED INTENSITY, WHILE A NOAA-21 MICROWAVE 
SOUNDER ESTIMATE SUPPORTED 75 KNOTS. ANALYSIS REVEALS AN ENVIRONMENT 
FAVORABLE FOR ADDITIONAL INTENSIFICATION, CHARACTERIZED BY LOW DEEP-
LAYER SHEAR, VERY WARM SSTS AND STRONG RADIAL OUTFLOW ALOFT.
INITIAL WIND RADII BASIS: PERSISTENCE 
CURRENT STEERING MECHANISM: SOUTHWESTERN FLANK OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) POSITIONED NEAR OKINAWA. 
AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T4.5 - 77 KTS
   DEMS: T4.0 - 65 KTS
   CIMSS SATCON: 68 KTS AT 250630Z
   CIMSS ADT: 55 KTS AT 250600Z
   CIMSS AIDT: 46 KTS AT 250600Z
   CIMSS D-MINT: 63 KTS AT 250547Z
   CIMSS D-PRINT: 71 KTS AT 250540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

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

3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TYPHOON (TY) 11W (NOUL) CONTINUES TRACKING
WEST-NORTHWESTWARD TOWARDS THE SOUTHEASTERN CHINESE COASTLINE. OVER
THE PAST SIX HOURS, THE TRACK HAS FLATTENED SLIGHTLY, LIKELY DUE TO
A PERSISTENT EXTENSION OF THE STR WHICH EXTENDS FROM SHANGHAI TO
NORTHERN VIETNAM. GLOBAL MODELS DEPICT THIS RIDGE EXTENSION
WEAKENING AND RETREATING RAPIDLY NORTHEASTWARD, WHICH WILL ALLOW TY
11W TO RESUME A MORE NORTHWESTWARD TRACK IN THE NEAR-TERM. LANDFALL 
IS EXPECTED TO OCCUR JUST EAST OF HONG KONG WITHIN THE NEXT 12 HOURS, 
AFTER WHICH THE SYSTEM WILL DECELERATE DUE TO INCREASING SURFACE 
FRICTION AND TERRAIN INTERACTION AS IT TURNS STEADILY POLEWARD AROUND 
THE PERIPHERY OF THE STR. THE ENVIRONMENT REMAINS FAVORABLE FOR 
ADDITIONAL INTENSIFICATION; HOWEVER, THE SHORT PERIOD OF TIME 
REMAINING OVER OPEN WATERS WILL PLACE A CAP ON THE PEAK INTENSITY. 
THE SYSTEM IS FORECAST TO REACH ITS PEAK INTENSITY OF 85 KNOTS 
SIMULTANEOUS WITH LANDFALL, AT TAU 12. ONCE OVER LAND, THE SYSTEM 
WILL RAPIDLY WEAKEN DUE TO LAND INTERACTION AND DISSIPATE OVER LAND 
BY TAU 48.  
MODEL DISCUSSION: TRACK GUIDANCE IS IN VERY STRONG AGREEMENT, WITH
MINIMAL CROSS- OR ALONG-TRACK UNCERTAINTY THROUGH LANDFALL. THE
GUIDANCE ENVELOPE BEGINS TO WIDEN SLIGHTLY AFTER LANDFALL BUT
REMAINS IN OVERALL STRONG AGREEMENT THROUGH THE ENTIRE FORECAST
PERIOD. THE JTWC TRACK IS PLACED NEAR THE MULTI-MODEL CONSENSUS
MEAN AND THE EXPERIMENTAL ARTIFICIAL INTELLIGENCE (AI) MODEL
TRACKER WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS ALSO IN GOOD
AGREEMENT, SHOWING A FLAT INTENSITY TREND THROUGH TAU 12, FOLLOWED
BY RAPID WEAKENING THROUGH THE REMAINDER OF THE FORECAST PERIOD.
THE SOLE OUTLIER IS THE IR15 RAPID INTENSIFICATION (RI) AID, WHICH
IS BASED ON THE NEAR-TERM SATELLITE INDICATORS PREDICTIVE OF FUTURE
RI. THE JTWC FORECAST DIVERGES FROM THE BULK OF THE GUIDANCE
PACKAGE IN THE NEAR-TERM AND FOLLOWS THE IR15 TO A PEAK OF 85
KNOTS, THEN REMAINING SLIGHTLY ABOVE MULTI-MODEL CONSENSUS THROUGH 
DISSIPATION. BASED ON THE OBSERVED TRENDS IN THE MSI AND EIR IMAGERY 
AS WELL AS MODEL-BASED GUIDANCE, THE JTWC INTENSITY FORECAST IS 
ASSESSED WITH HIGH CONFIDENCE. 
FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: HIGH//
NNNN