WDPN31 PGTW 130300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (LAN) WARNING NR 022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 29.7N 139.4E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 336 NM SOUTH OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 32 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN 80 NM
WIDE EYE WITH MULTIPLE MESOVORTICES ROTATING ABOUT A COMMON CENTER.
THE COLD RING OF -60 TO -70 CELSIUS CLOUD TOPS HAS STRUGGLED TO
FULLY CLOSE OFF AROUND THE EYE, BUT THE OVERALL CLOUD PATTERN HAS
NOT DECAYED OVER THE PAST SIX HOURS AND HAS REMAINED STEADY IN
PRESENTATION. UPPER-LEVEL OUTFLOW HAS BECOME MORE RADIAL, AS SOME
EXPANSION POLEWARD IS NOW NOTED. THE INITIAL INTENSITY IS SET AT 70
KT BASED ON TWO COINCIDENT SAR PASSES THAT CAME IN AROUND 122030Z,
BOTH OF WHICH SHOWED REPRESENTATIVE MAX WINDS OF ABOUT 70 KT IN THE
NORTHEAST AND SOUTHWEST QUADRANTS.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T4.5 - 77 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T4.0 - 65 KTS
   CIMSS ADT: 84 KTS AT 122340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL
   OTHER FACTORS: DRY AIR MASS TO THE WEST

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: TYPHOON 07W (LAN) CONTINUES TO EXHIBIT A VERY
BROAD CORE RING OF MAXIMUM WINDS WITH A RADIUS OF 40 NM, OWING TO THE 
DEMOLITION OF THE INNER CORE BY REDUCED OCEAN HEAT FLUXES DURING THE 
PAST 24HOURS. LAN IS NOW MOVING INTO AN AREA OF SLIGHTLY HIGHER OCEAN 
HEAT CONTENT AS IT TRACKS NORTHWESTWARD NEAR THE EASTERN SIDE OF A 
DEEP WARM EDDY. THIS WILL LIKELY PREVENT FURTHER WEAKENING, AND MAY 
EVEN RESULT IN SLIGHT REINTENSIFICATION OF THE VORTEX AS IT TRACKS
AROUND THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE TOWARDS
CENTRAL HONSHU. HOWEVER, THE BROAD NATURE OF THE VORTEX WILL LIKELY
LIMIT THE PACE OF STRENGTHENING, IF ANY. DYNAMICAL MODELS ARE IN
GOOD AGREEMENT ON THE LANDFALL LOCATION, BUT HAVE SHIFTED WESTWARD
SLIGHTLY SINCE THE LAST CYCLE, AND THE JTWC TRACK FORECAST HAS
FOLLOWED SUIT WITH A SLIGHT WESTWARD SHIFT. MODELS ARE IN GOOD
AGREEMENT THAT LAN WILL CROSS HONSHU BETWEEN 48 AND 72 HOURS,
EMERGING OVER THE SEA OF JAPAN AND TURNING NORTHEASTWARD.
INTERACTION WITH UPPER-LEVEL TROUGHING OVER NORTHEASTERN CHINA AND
A COOLER AIR MASS IS EXPECTED TO INITIATE EXTRATROPICAL TRANSITION
DURING THE 96-120 HOUR PERIOD, COMPLETING BY 120 HOURS AS THE WARM
CORE STRUCTURE OF THE STORM DISSOLVES.

MODEL DISCUSSION: THE JTWC TRACK FORECAST IS SLIGHTLY TO THE RIGHT
OF THE MULTI-MODEL CONSENSUS, AND A LITTLE WEST OF THE PREVIOUS
FORECAST. THE JTWC INTENSITY FORECAST IS CLOSE TO THE MULTI-MODEL
CONSENSUS AND IS SIMILAR TO THE PREVIOUS FORECAST.

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