WDPN31 PGTW 141500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (LAN) WARNING NR 028//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 32.7N 136.6E
   INITIAL INTENSITY: 85 KTS
   GEOGRAPHIC REFERENCE: 219 NM SOUTHWEST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 40 FEET

SATELLITE ANALYSIS, INITIAL POSITION, AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY (GOES H-8 PROXY
VIS) SHOWS A MEDIUM-SIZED SYMMETRICAL CYCLONE THAT HAS MAINTAINED
ITS OVERALL CONVECTIVE AND WRAP STRUCTURE WITH A LARGE 40-NM
BANDING EYE, EXPOSING A RAGGED AND IRREGULAR BUT DEFINED LOW LEVEL 
CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH HIGH 
CONFIDENCE BASED ON THE EXPOSED LLCC FEATURE, CONCENTRIC WITH AN 
EQUALLY LARGE LLCC IN A COMPOSITE RADAR LOOP FROM JMA AND LINED UP 
WITH A DEFINED LLCC FEATURE IN THE 140920Z SSMIS. THE INITIAL 
INTENSITY OF 85KTS IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON THE 
140859Z SAR PASS INDICATING 85KT WINDS CIRCLING TWO-THIRDS OF THE 
EYEWALL AND REFLECTS THE SUSTAINED 6-HR STRUCTURE. THE INITIAL 
INTENSITY IS ALSO SUPPORTED BY THE HIGH END OF AGENCY AND AUTOMATED 
DVORAK ESTIMATES. ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH LOW 
VWS AND MODERATE OUTFLOW OFFSET BY LOCALIZED LOW SST AND OHC VALUES 
DUE TO OCEANIC UPWELLING AND DRY AIR INTRUSION.

INITIAL WIND RADII BASIS: SAR DATA.

CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) TO
THE NORTHEAST.


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.5 - 77 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T4.5 - 77 KTS
   CIMSS SATCON: 80 KTS AT 141210Z
   CIMSS ADT: 79 KTS AT 141120Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 0-5 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: DRY AIR INTRUSION WRAPPING IN FROM THE NORTHWEST.

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 LAN WILL CONTINUE ON ITS CURRENT
NORTHWESTWARD TRACK AND MAKE LANDFALL BEFORE TAU 12 OVER WAKAYAMA
PREFECTURE THEN INLAND JUST TO THE WEST OF KYOTO, EXIT INTO THE SEA
OF JAPAN (SOJ) BY TAU 12. AFTERWARD, IT WILL TRACK MORE NORTHWARD,
CREST THE STR AXIS BEFORE TAU 24 THEN ACCELERATE NORTHEASTWARD AS
THE STR RECEDES IN RESPONSE TO A MID-LATITUDE TROUGH APPROACHING
FROM THE NORTHWEST, AND CLIPPING THE NORTHERN TIP OF HOKKAIDO JUST
BEFORE TAU 72. THE MARGINAL ENVIRONMENT WILL BECOME UNFAVORABLE
WITH DRY AIR INTRUSION, INCREASING VWS, THEN LAND INTERACTION
REDUCING IT TO 60KTS BY TAU 24. DESPITE THE RELATIVELY WARM SST IN
THE SOJ, INCREASING VWS THEN INTERACTION WITH THE BAROCLINIC ZONE
AS TY 07W BEGINS EXTRA-TROPICAL TRANSITION BY TAU 48 WILL GRADUALLY
ERODE IT TO A 40-KT COLD CORE LOW BY TAU 72.  

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY GOOD AGREEMENT WITH
A GRADUAL AND EVEN SPREAD TO JUST 129NM BY TAU 72, LENDING HIGH
CONFIDENCE TO THE JTWC TRACK FORECAST. THERE IS ONLY MEDIUM
CONFIDENCE IN THE JTWC INTENSITY FORECAST DUE TO UNCERTAINTIES
INHERENT WITH EXTRA-TROPICAL TRANSITION, I.E., EXPANDING WIND FIELD
AND ABSORPTION INTO THE BAROCLINIC ZONE.

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