WDPN31 PGTW 142100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (LAN) WARNING NR 029//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 33.4N 136.1E
   INITIAL INTENSITY: 80 KTS
   GEOGRAPHIC REFERENCE: 212 NM WEST-SOUTHWEST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 33 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A LARGE,
CLOUD-FILLED, 45NM WIDE EYE FEATURE IN THE CENTER OF WEAK AND
FRAGMENTED CONVECTIVE BANDS. ANIMATED RADAR DATA FROM JMA INDICATE
THE SYSTEM IS IN THE PROCESS OF MAKING LANDFALL ALONG THE COAST OF
CAPE SHINONO, NEAR THE TOWN OF SHINGU. A 141700Z GPM 37GHZ MICROWAVE
IMAGE SHOWED THICK, WELL-DEFINED LOW-LEVEL RAIN BANDS SURROUNDING A
30NM WIDE MICROWAVE EYE FEATURE, WHILE THE 89GHZ IMAGE SHOWED MUCH
WEAKER FRAGMENTED CONVECTIVE BANDS AROUND A MUCH LARGER, 70NM WIDE
EYE IN THE UPPER-LEVELS. THE INITIAL POSITION IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE RADAR FIX DATA AS WELL AS AN EXTRAPOLATION
OF THE GPM 37GHZ EYE FEATURE. THE INITIAL INTENSITY IS ASSESSED
WITH MEDIUM CONFIDENCE, HEDGED HIGHER THAN THE BULK OF SUBJECTIVE
AND OBJECTIVE INTENSITY ESTIMATES IN LIGHT OF AN EARLIER 140859Z
RCM-1 SAR PASS, WHICH INDICATED WINDS BETWEEN 85-89 KNOTS
SURROUNDING TWO-THIRDS OF THE CIRCULATION CENTER. WIND SPEEDS ALONG
THE COAST HAVE BEEN RELATIVELY LOW COMPARED TO THE OVERWATER
INTENSITIES, BUT WINDS ARE ALREADY ABOVE 40 KNOTS AT KANSAI
AIRPORT, EXPOSED IN OSAKA BAY. WINDS WILL INCREASE AS THE SYSTEM
TRACKS CLOSE BY THE AIRPORT IN THE NEXT FEW HOURS. THE INITIAL
CENTRAL PRESSURE HAS BEEN ADJUSTED TO 970MB BASED ON AN
EXTRAPOLATION OF A 975MB MEAN SEA LEVEL PRESSURE (MSLP) READING
FROM CAPE SHINONO ON THE OUTER PERIPHERY OF THE EYE AS IT PASSED.
THE WIND RADII HAVE ALSO BEEN ADJUSTED SIGNIFICANTLY SMALLER BASED
ON THE PREVIOUSLY MENTIONED SAR DATA AND A 141217Z ASCAT-B PASS.
ENVIRONMENTAL CONDITIONS ARE MARGINALLY FAVORABLE, WITH ROBUST
POLEWARD OUTFLOW AND LOW SHEAR OFFSET BY TERRAIN INFLUENCES WHICH
WILL TEAR UP THE LOW-LEVEL CORE.

INITIAL WIND RADII BASIS: SCATTEROMETER AND SAR DATA. 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) TO THE EAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T4.0 - 65 KTS
   CIMSS ADT: 61 KTS AT 141750Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 0-5 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: NOW MAKING LANDFALL, TYPHOON (TY) 07W (LAN) IS
FORECAST TO CONTINUE TRACKING NORTHWESTWARD, INTO OSAKA BAY AND
THEN TURN MORE NORTHWARD AND EMERGE INTO THE SOUTHWESTERN SEA OF
JAPAN BY TAU 24. TRACK SPEEDS SHOULD SLOW DOWN AS IT TRANSITS
ACROSS THE RUGGED TERRAIN DUE TO FRICTIONAL EFFECTS, BUT THEN JUMP
UP ONCE THE REMAINING LLCC MOVES BACK OVER OPEN WATERS. THE SYSTEM
WILL GRADUALLY TURN NORTH-NORTHEASTWARD AFTER TAU 24 AS THE
STEERING RIDGE TO THE EAST IS ERODED BY THE APPROACH OF A
MID-LATITUDE TROUGH MOVING EAST OVER SOUTHEASTERN RUSSIA. WHILE THE
BULK OF THE MODEL GUIDANCE SUPPORTS THE FORECAST TRACK TO THE
NORTHEAST, INCREASING NUMBERS OF ENSEMBLE MEMBERS FROM BOTH THE
GEFS AND ECENS ARE BEGINNING TO BRING THE SYSTEM INTO SOUTHERN
RUSSIA, TO THE EAST OF VLADIVOSTOK WITHIN THE FIRST 48 HOURS OF THE
FORECAST. THERE IS SOME SUPPORT FOR THIS SCENARIO IN THE GFS
DEEP-LAYER MEAN STEERING PATTERN, WHICH SHOWS AN EXTENSION OF THE
STEERING RIDGE BUILDING IN TOWARDS THE WEST ACROSS THE NORTHERN SEA
OF JAPAN, AND HOLDING THE SYSTEM ON A TRACK FURTHER TOWARDS
THE WEST. THE CURRENT FORECAST TRENDS TOWARDS THE WEST BUT HOLDS TO
THE RECURVE SCENARIO FOR NOW, BUT THE ALTERNATE SCENARIO BEARS
WATCHING. ON THE CURRENT FORECAST TRACK, IF THE CORE OF THE SYSTEM
CAN MAKE IT ACROSS HONSHU IT WILL HAVE A SHORT PERIOD OF TIME TO
MAINTAIN INTENSITY AS IT MOVES ACROSS VERY WARM WATERS (28C), AND
TAPS INTO STRONG POLEWARD OUTFLOW INTO THE BASE OF THE TROUGH
PASSING TO THE NORTH. AFTER TAU 36 HOWEVER, SHEAR WILL COME TO
DOMINATE OVER THE OUTFLOW AND TEAR THE SYSTEM APART, LEADING TO
RAPID WEAKENING. THE SYSTEM WILL COMMENCE EXTRATROPICAL TRANSITION
(ETT) AROUND TAU 48, COMPLETING TRANSITION TO A GALE-FORCE
EXTRATROPICAL LOW OVER SAKHALIN ISLAND BY TAU 72. 

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN GOOD AGREEMENT
ON THE RECURVE SCENARIO, WITH ALL MEMBERS OF THE TRACK CONSENSUS
CONTAINED WITHIN AN ENVELOPE THAT GRADUALLY EXPANDS TO 160NM BY TAU
72. AS MENTIONED ABOVE, THE MAJORITY OF THE ENSEMBLE MEMBERS ALSO
SUPPORT THE RECURVE SCENARIO BUT INCREASING NUMBERS OF MEMBERS ARE
STARTING TO PULL THE SYSTEM ONTO A DUE NORTH TRACK INTO SOUTHERN
RUSSIA. THE JTWC FORECAST REMAINS CONSISTENT WITH THE PREVIOUS
FORECAST BUT DOES SHIFT THE TRACK ABOUT 30NM TO THE WEST AFTER TAU
24. CONFIDENCE REMAINS MEDIUM DUE TO THE INCREASING UNCERTAINTY IN
THE ENSEMBLE GUIDANCE. INTENSITY GUIDANCE IS IN RELATIVELY GOOD
AGREEMENT, WITH ALL CONSENSUS MEMBERS SHOWING WEAKENING THROUGH THE
FORECAST, WHILE THE HWRF AND HAFS-A INDICATE A SHORT PERIOD OF
ARRESTED WEAKENING IN THE SEA OF JAPAN THROUGH TAU 36. THE JTWC
FORECAST LIES VERY CLOSE TO THE HAFS-A SOLUTION, THOUGH AS WITH THE
TRACK FORECAST, UNCERTAINTY AS TO THE EXACT TRACK AFTER TAU 24
INTRODUCES UNCERTAINTY INTO THE INTENSITY FORECAST AS WELL, LEADING
TO OVERALL MEDIUM CONFIDENCE. 

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