WDPN31 PGTW 111500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (LAN) WARNING NR 016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.9N 142.6E
   INITIAL INTENSITY: 105 KTS
   GEOGRAPHIC REFERENCE: 468 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 35 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS WARMING
CONVECTIVE CLOUD TOPS SURROUNDING A STILL WELL-DEFINED 29 NM
DIAMETER EYE, REFLECTING THE FIRST STAGE OF A WEAKENING TREND. A
PREVIOUSLY ROBUST POLEWARD OUTFLOW CHANNEL HAS CONTINUED TO WANE
AS THE DRIVING MECHANISM, AN UPPER-LEVEL LOW TO THE NORTH, MOVES
AWAY FROM THE SYSTEM. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON BASED ON THE CLEAR EYE FEATURE EVIDENT IN THE
EIR AND 111137Z METOP-B MHS 89 GHZ MICROWAVE IMAGERY. THE CURRENT
POSITION CONFIRMS THAT TY 07W IS BEGINNING AN ANTICIPATED TURN
TOWARD THE NORTHWEST AS RIDGING BUILDS TO THE NORTH AND EAST OF THE
SYSTEM. THE INITIAL INTENSITY OF 105 KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON MULTI-AGENCY ON SUPPORTIVE, MULTI-AGENCY
SUBJECTIVE DVORAK AND UW-CIMSS OBJECTIVE SATELLITE INTENSITY
ESTIMATES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.0 - 115 KTS
   RJTD: T6.0 - 115 KTS
   RCTP: T5.5 - 102 KTS
   KNES: T6.0 - 115 KTS
   CIMSS SATCON: 108 KTS AT 111200Z
   CIMSS ADT: 112 KTS AT 111130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TY 07W WILL CONTINUE ITS TURN TOWARD THE
NORTHWEST OVER THE NEXT SIX HOURS AS SUBTROPICAL RIDGING BUILDS TO
THE NORTH AND EAST, UNINHIBITED BY FEATURES ASSOCIATED WITH THE
MID-LATITUDE BAROCLINIC ZONE WELL TO THE NORTH. THE SYSTEM WILL
FOLLOW THE FLOW ASSOCIATED WITH THE CURRENT STEERING RIDGE
THROUGHOUT THE FORECAST PERIOD, FIRST NORTHWESTWARD THROUGH TAU 36
AND INCREASINGLY POLEWARD THEREAFTER. A DEEP-LAYER TROUGH WILL DIG
EQUATORWARD TO THE NORTHWEST OF THE SYSTEM IN THE EXTENDED PERIOD,
SETTING A LIMIT TO THE WESTERN EXTENT OF THE STEERING RIDGE AND THE
DEPENDENT STORM TRACK. TY 07W IS STILL EXPECTED TO MAKE LANDFALL AT
TYPHOON INTENSITY SOUTHEAST OF KYOTO AND OSAKA JUST AFTER TAU 72,
ALTHOUGH DECLINING OCEAN HEAT CONTENT, CONTENTION WITH DRIER AIR
UPSTREAM, AND REDUCED DIVERGENCE ALOFT WILL CONTINUE TO SLOWLY
WEAKEN THE SYSTEM. IN THE EXTENDED RANGE PASSAGE OVER LAND AND 
INTERACTION WITH A DEVELOPING TROUGH TO THE NORTHWEST WILL
ACCELERATE THE WEAKENING TREND AND INDUCE THE BEGINNING OF
EXTRATROPICAL TRANSITION. 

MODEL DISCUSSION: THE ENVELOPE OF GLOBAL AND ENSEMBLE MODEL TRACK
FORECAST SOLUTIONS HAS NARROWED SINCE THE LAST CYCLE, WITH GREATER
UNCERTAINTY REMAINING IN THE EXTENDED PERIOD REGARDING THE TIMING OF 
THE EXPECTED TURN TO THE NORTH AND POST-TURN TRACK SPEED. THEREFORE,
CONFIDENCE IN THE TRACK FORECAST IS MEDIUM EARLY ON AND LOW IN THE 
EXTENDED PERIOD. INTENSITY FORECASTS ARE IN GOOD AGREEMENT THROUGH 
MOST OF THE FORECAST PERIOD, AND THE ENVIRONMENTAL FACTORS AT PLAY 
ARE 
FAIRLY STRAIGHTFORWARD. HOWEVER, THERE IS SOME UNCERTAINTY REGARDING 
HOW THE CURRENTLY OBSERVED CHANGES IN STORM STRUCTURE WILL PROCEED, 
LENDING OVERALL MEDIUM CONFIDENCE TO THE PREDICTED INTENSITY. 

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