WDPN31 PGTW 100900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (LAN) WARNING NR 011//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.5N 143.5E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 119 NM SOUTHEAST OF CHICHI JIMA
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A RELATIVELY
SMALL, TYPHOON STRENGTH CIRCULATION WITH A ROUGHLY 30NM RAGGED EYE
FEATURE. A RECENT 100400Z AMSR2 89GHZ MICROWAVE IMAGE REVEALS A
SINGLE DOMINANT BAND OF DEEP CONVECTION NEARLY ENCIRCLING THE LLCC,
BEYOND WHICH THERE IS MINIMAL ORGANIZED DEEP CONVECTIVE ACTIVITY.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON MSI
AND AMSR2 IMAGERY. THE INITIAL INTENSITY OF 70 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED PRIMARILY ON AGENCY DVORAK INTENSITY
ESTIMATES WHICH ALL SUPPORT 75KTS. THE BULK OF THE REMAINING
AUTOMATED INTENSITY ESTIMATES ARE SUSPICIOUSLY HIGH, IN MOST CASES
HOVERING AROUND 100KTS WHICH BASED ON CONFIRMATION FROM PREVIOUS
SAR AND SMAP PASSES IS WELL BEYOND REALITY.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WESTERN PERIPHPERY OF A SUBTROPICAL
RIDGE (STR)

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   CIMSS ADT: 102 KTS AT 100540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EASTWARD

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: TY 07W (LAN) IS FORECAST TO CONTINUE TRACKING
NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR TO THE EAST.
OVER THE NEXT TWO DAYS, FUELED BY LOW VERTICAL WIND SHEAR AND WARM
SEA SURFACE TEMPERATURES, 07W IS FORECAST TO REACH 90KTS BY TAU 48.
AS THE STR TO THE EAST REORIENTS AND SHIFTS, TRACK SPEEDS WILL
INCREASE AS THE SYSTEM PASSES 30N. BY TAU 72, SUBSTANTIAL DRY AIR
AND SUBSIDENCE ALOFT WILL CONSPIRE TO GRADUALLY WEAKEN THE SYSTEM
AS IT STEADIES UP ON A COLLISION COURSE WITH MAINLAND JAPAN. BASED
ON THE OTHERWISE FAVORABLE CONDITIONS OF THE SSTS AND SHEAR VALUES,
07W IS FORECAST TO MAKE LANDFALL AS A TYPHOON, PROCEEDING INLAND
AND IMPACTING THE KANTO PLAIN AND YOKOSUKA AREAS.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH ALL
MEMBERS GENERALLY FOLLOWING THE JTWC FORECAST TRACK AND IMPACTING
JAPAN BY TAU 100 JUST WEST OF TOKYO. THERE IS A MODERATE AMOUNT OF
CROSS TRACK SPREADING WITH TIME, AS NVGM HEADS FOR KYOTO TO THE
WEST AND COAMPS-TC (GFS) HEADS FOR MISAWA TO THE EAST, WITH THE
BULK OF THE REMAINING MEMBERS DOWN THE MIDDLE. FOR THIS REASON THE
JTWC TRACK FORECAST IS PLACED WITH OVERALL MEDIUM CONFIDENCE.
RELIABLE MODEL INTENSITY GUIDANCE IS IN GOOD AGREEMENT WITH ALL
MEMBERS INTENSIFYING THE SYSTEM THROUGH TAU 48, AFTER WHICH A
GRADUAL WEAKENING TREND THROUGH LANDFALL. FOR THIS REASON THE JTWC
INTENSITY FORECAST IS ALSO PLACED WITH OVERALL MEDIUM CONFIDENCE.

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