WDPN31 PGTW 082100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (LAN) WARNING NR 
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 24.4N 147.6E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 344 NM EAST OF IWO TO, JAPAN
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE SYSTEM
CONTINUED TO CONSOLIDATE AS DEEP CONVECTION HAS NOW WRAPPED ALMOST
COMPLETELY AROUND THE LOW LEVEL CIRCULATION (LLC) FORMING THE EARLY
STAGE OF A BANDING EYE. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE FORMATIVE EYE THAT LINED UP WELL WITH A
MICROWAVE EYE FEATURE IN THE 081752Z SSMIS 37GHZ IMAGE. THE
INITIAL INTENSITY IS ALSO PLACED WITH HIGH CONFIDENCE BASED ON THE
HIGH END OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE
6-HR IMPROVEMENT. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT WITH
WARM SST, LOW VWS, AND EFFICIENT VENTILATION ALOFT.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

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



AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 41 KTS AT 081740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG EQUATORWARD
   OTHER FACTORS: STRONG EASTWARD OUTFLOW INTO A TUTT CELL.

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TS LAN WILL CONTINUE ON ITS CURRENT TRACK
UNDER THE STEERING STR. AFTER TAU 36, IT WILL TRACK MORE
NORTHWESTWARD TOWARD YOKOSUKA, JAPAN, AS THE STR RECEDES WITH THE
APPROACH OF A MID-LATITUDE TROUGH FROM THE NORTHWEST. THE FAVORABLE
ENVIRONMENT WILL FUEL A STEADY INTENSIFICATION TO A PEAK OF 80KTS
BY TAU 96. AFTERWARD, INCREASING VWS AND COOLING SST WILL BEGIN TO
WEAKEN THE SYSTEM, DOWN TO 70KTS BY TAU 120.



MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT WITH A
GRADUAL AND EVEN SPREAD TO A MERE 105NM BY TAU 120, LENDING HIGH
CONFIDENCE TO THE JTWC TRACK AND INTENSITY FORECASTS.


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