WDPN33 PGTW 141500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 08W (AMPIL) WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.6N 141.1E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 468 NM SOUTH OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 29 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
COMPACT, WELL-ORGANIZED CORE, WITH WHAT APPEARS TO BE A BEGINNING
OF EYE DEVELOPMENT, INDICATING POTENTIAL FOR RAPID INTENSIFICATION.
SUBSEQUENT IMAGERY SHOWS A CLEAR PINHOLE EYE FEATURE, THE ONLY
QUESTION IS, WILL THE EYE PERSIST. SYSTEM EXHIBITS A MODERATE
POLEWARD AND EQUATORWARD OUTFLOW, WITH ASSOCIATED SPIRAL BANDS OF
DEEP CONVECTION. THERE IS STILL MINOR DRY AIR INTRUSION INJECTING
INTO THE CORE OF THE SYSTEM FROM THE WEST, BUT IT APPEARS TO NOT
SIGNIFICANTLY HINDER FURTHER INTENSITY DEVELOPMENT AT THIS TIME,
BUT MAINTAINS SLIGHTLY ASYMMETRICAL STRUCTURE OF THE STORM. A
141106Z ASCAT-B BULLSEYE PASS REVEALED A SMALL INNER CORE, WITH
WINDS APPROACHING 65 KNOTS IN THE SCATTEROMETER DATA. AN EARLIER
140846Z RCM-3 SAR PASS DEPICTED A STRONGER WIND FIELD, WITH MAXIMUM
WINDS UP TO 79 KNOTS, AND A SLIGHTLY LARGER 34 AND 50 KNOT WIND
RADII. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
THE DEVELOPING EYE FEATURE, AS WELL AS THE ASCAT WINDSPEED MINIMA.
THE INITIAL INTENSITY OF 65 KTS IS ASSESSED WITH HIGH CONFIDENCE
BASED ON SAR WIND FIELDS, AND THE STRONG AGREEMENT ACROSS FOUR
AGENCY DVORAK ESTIMATES OF T4.0, A 141400Z SATCON ESTIMATE OF 65
KNOTS AND A CIMSS DPRINT ESTIMATE OF 70 KNOTS.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: TRANSITIONING BETWEEN NEAR-EQUATORIAL
RIDGE TO THE SOUTHEAST AND STRONG SUBTROPICAL RIDGE TO THE
EAST-NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T4.0 - 65 KTS
   CIMSS SATCON: 65 KTS AT 141400Z
   CIMSS ADT: 43 KTS AT 141400Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
   OTHER FACTORS: DRY AIR IN THE WESTERN PORTION OF THE
CIRCULATION. 

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: THE NEAR-EQUATORIAL RIDGE (NER) LOCATED TO THE
SOUTHEAST OF TYPHOON 08W (AMPIL) IS CURRENTLY HANDING OFF THE
PRIMARY STEERING TO THE STRONG SUBTROPICAL RIDGE (STR) LOCATED TO
THE NORTHEAST OF THE SYSTEM. TY 08W IS NOW EXPECTED TO COMMENCE A
TURN NORTHWARD IMMINENTLY AS THE STR ASSUMES THE DOMINANT STEERING
ROLE, AND THEN ACCELERATE NORTHWARD, WHILE RAPIDLY INTENSIFYING,
PRIMARILY BETWEEN TAU 24 AND 36. ROUGHLY BETWEEN TAU 36 AND TAU 48,
AND NOT DEPICTED ON THE FORECAST GRAPHIC, TY AMPIL IS FORECAST O
REACH PEAK INTENSIFY OF 110-115 KNOTS, WHILE IT SKIRTS THE BOSO
PENINSULA AND THE TOKYO REGION. CURRENT TRACK GUIDANCE ESTIMATES
THE CPA TO BE APPROXIMATELY 60 NM FROM YOKOSUKA BY APPROXIMATELY
TAU 48, AFTER WHICH THE SYSTEM WILL ROUND THE STR AXIS AND RAPIDLY
ACCELERATE TOWARDS THE NORTHEAST. THE BEGINNING OF EXTRATROPICAL
TRANSITION (ETT) BY TAU 96, WITH FULL TRANSITION TO A NEAR
STORM-FORCE EXTRATROPICAL LOW PRESSURE AREA NO LATER THAN TAU 120. 

MODEL DISCUSSION: MODEL GUIDANCE REMAINS IN CLOSE AGREEMENT IN
REGARDS TO THE TY 08W TRACK, WITH MAJORITY OF THE DETERMINISTIC
MODELS AND ENSEMBLE MEMBERS TRACKING THE TYPHOON VORTEX JUST EAST
OF THE COAST OF JAPAN. GFS ENSEMBLE MEAN IS LEANING TOWARDS A
SLIGHTLY CLOSER CPA THAN THE MULTI-MODEL CONSENSUS, AND AS IT IS
CURRENTLY THE BEST PERFORMING GUIDANCE, JTWC FORECAST IS ALSO
LEANING TOWARDS THAT APPROACH. THE JTWC TRACK FORECAST THEREFORE
LIES ON THE WESTERN EDGE OF THE GUIDANCE ENVELOPE AT TAU 48, CLOSE
TO THE GFS DETERMINISTIC TRACKER AND JUST A BIT EAST OF THE
NON-INTERPOLATED AEMN TRACKER. IN TERMS OF INTENSITY, THE JTWC
FORECAST IS LESS AGGRESSIVE OVER THE NEXT 24 HOURS THAN SOME OTHER
GUIDANCE, INCLUDING HAFS-A AND COAMPS-TC, BUT GOES ABOVE THE
MULTI-MODEL CONSENSUS, AND ESTIMATING THE POTENTIAL FOR MAXIMUM
INTENSITY TO OCCUR BETWEEN THE FORECAST TIME STEPS OF TAU 36 AND
48. IN THIS CASE, THE PEAK INTENSITY MAY REACH 5-10 KTS ABOVE THE
FORECASTED 105 KTS FOR EACH OF THE TAUS 36 AND 48. FOLLOWING THAT,
NEARLY ALL MODELS CALL FOR STEADY WEAKENING OF THE SYSTEM, WITH
JTWC FORECAST GOING FROM 105 KTS AT TAU 48 TO 45 KTS AT TAU 120.

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