WDPN31 PGTW 150300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (LAN) WARNING NR 
030//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 34.3N 135.4E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 220 NM WEST-SOUTHWEST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 11 KTS
   SIGNIFICANT WAVE HEIGHT: XX FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL STORM (TS) 07W (LAN) MADE LANDFALL NEAR CAPE SHIONO AROUND
1900Z AS A TYPHOON STRENGTH SYSTEM. NOW HAVING MOVED RAPIDLY INLAND
OVER ROUGH TERRAIN, THE SYSTEM HAS SIGNIFICANTLY WEAKENED AND
DETERIORATED. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) NO
LONGER SHOWS A DISTINCT EYE, AND EVEN THE JMA RADAR DATA NOW
DEPICTS A VERY RAGGED CENTER, CURRENTLY PASSING OVER THE KANSAI
AIRPORT AREA AND MOVING INTO OSAKA BAY. SURFACE OBSERVATIONS FROM
AROUND OSAKA BAY SHOW MAXIMUM SUSTAINED 10-MIN WINDS OF AROUND 55
KNOTS WITH GUSTS UPWARDS OF THE HIGH 60S EARLIER, HAVING BACKED
DOWN AS THE CENTER HAS APPROACHED OVER THE PAST COUPLE OF HOURS.
THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON RJTD
RADAR FIX POSITIONS, ANALYSIS OF SURFACE WIND OBSERVATIONS AND THE
ANIMATED MSI. THE INITIAL INTENSITY IS LOWERED TO 60 KNOTS WITH
MEDIUM CONFIDENCE, ON THE HIGHER END OF THE VERY LIMITED OVERLAND
INTENSITY ESTIMATES SUCH AS DPRINT AND DMINT, COMING IN AT 52 KNOTS
AND 58 KNOTS RESPECTIVELY AND THE RJTD AND RCTP OVERLAND FIXES
RANGING FROM T3.0 TO T3.5. ENVIRONMENTALLY, IF ONE REMOVES THE LAND
INTERACTION WHICH IS DECIMATING THE LOW-LEVEL CORE, AND THE LACK OF
A ENERGY SOURCE OVER LAND, CONDITIONS ARE FAIRLY GOOD WITH ROBUST
POLEWARD OUTFLOW AND LOW VERTICAL WIND SHEAR (VWS). THE SYSTEM IS
MOVING FAIRLY QUICKLY TO THE NORTHWEST ALONG THE WESTERN SIDE OF A
DEEP-LAYER SUBTROPICAL RIDGE (STR) TO THE EAST.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED FAR TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   RJTD: T3.0 - 45 KTS
   RCTP: T3.5 - 55 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: TERRAIN INTERACTION. 

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: OVER THE NEXT 12 HOURS, TS LAN WILL TRANSIT
ACROSS WESTERN HONSHU, PASSING VERY CLOSE TO KOBE, THEN EMERGING
BACK INTO THE SEA OF JAPAN TO THE NORTH OF TOYOOKA BY TAU 12. AFTER
TAU 12, THE SYSTEM WILL GRADUALLY TURN ONTO A MORE NORTH, THEN
NORTHEASTWARD TRACK THROUGH THE REMAINDER OF THE FORECAST PERIOD,
GENERALLY STEERING UP THE WESTERN SIDE OF THE SUBTROPICAL RIDGE
COMPLEX CENTERED ROUGHLY ALONG THE 150E LONGITUDE. THE JTWC
FORECAST HAS SHIFTED SLIGHTLY FURTHER WEST ONCE AGAIN, AS THE
ENSEMBLE MEAN TRACKS OF ALL AVAILABLE ENSEMBLE GUIDANCE INCLUDING
ECENS, GEFS, MOGREPS AND COAMPS-TC SUGGEST A SHIFT WESTWARD WITH
EACH SUCCESSIVE MODEL UPDATE. THE TRACK HOWEVER REMAINS OVER WATER
IN THE SEA OF JAPAN FOR THE DURATION OF THE FORECAST, EVEN IF IT IS
STEADILY INCHING CLOSER TO RUSSIA. BASED ON THE RAPID WEAKENING
SEEN IN THE PAST SIX HOURS SINCE LANDFALL, THE EXPECTED INTENSITY
UPON REENTRY INTO THE SEA OF JAPAN HAS BEEN LOWERED SLIGHTLY, TO 50
KNOTS. ONCE BACK OVER WATER, WARM SSTS AND ROBUST POLEWARD OUTFLOW
WILL COMPETE WITH STEADILY INCREASING SHEAR, RESULTING IN A PERIOD
OF STAGNANT INTENSITY BETWEEN TAU 12 AND TAU 36. AFTER TAU 36, SSTS
COOL DRAMATICALLY, SHEAR WILL COME TO DOMINATE THE ENVIRONMENT AND
THE SYSTEM WILL BEGIN TO TRANSITION TO AN EXTRATROPICAL LOW WHILE
AT THE SAME TIME RAPIDLY WEAKENING. COMPLETION OF EXTRATROPICAL
TRANSITION (ETT) IS ANTICIPATED BY TAU 72 AS THE SYSTEM MOVES INTO
THE SEA OF OKHOTSK. 

MODEL DISCUSSION: CONSISTENT WITH THE PREVIOUS FORECAST,
DETERMINISTIC TRACK GUIDANCE REMAINS IN VERY GOOD AGREEMENT, WITH
THE CONSENSUS MEMBERS CONFINED TO A VERY TIGHT ENVELOPE THROUGH THE
FORECAST PERIOD. HOWEVER THE ENTIRETY OF THE GUIDANCE PACKAGE,
ALONG WITH THE ENSEMBLE MEANS AND THE SUPER-ENSEMBLE MEAN,
CONTINUES TO WALK WESTWARD WITH EACH SUCCESSIVE MODEL RUN. SO WHILE
CONFIDENCE IS HIGH IN A GENERAL SENSE, THE PROGRESSIVE SHIFT OF THE
GUIDANCE PACKAGE INTRODUCES UNCERTAINTY INTO THE FORECAST,
RESULTING IN MEDIUM CONFIDENCE IN THE FORECAST TRACK. INTENSITY
GUIDANCE REMAINS VERY CONSISTENT WITH THE PREVIOUS RUN IN TERMS OF
THE OVERALL TRAJECTORY OF THE INTENSITY CHANGE, WITH THE MESOSCALE
MODELS SUGGESTING A PERIOD OF STAGNATE INTENSITY IN THE
MIDDLE-RANGE OF THE FORECAST, FOLLOWED BY RAPID WEAKENING
THEREAFTER. THE JTWC FORECAST REMAINS CONSISTENT WITH THE HAFS-A
GUIDANCE, WITH MEDIUM CONFIDENCE. 

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