WDPN32 PGTW 070900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (FOURTEEN) WARNING NR 
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.0N 134.8E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 690 NM SOUTHEAST OF KADENA AB, OKINAWA,
JAPAN
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A MEDIUM-SIZED
DEVELOPING SYSTEM WITH DEEPENING FORMATIVE BANDS FEEDING INTO A
RAGGED CENTRAL DENSE OVERCAST THAT CONTINUES TO OBSCURE THE LOW
LEVEL CIRCULATION CENTER. THE INITIAL POSITION IS PLACED WITH
MEDIUM CONFIDENCE USING LOW CLOUD TRACING IN THE MSI LOOP INTO A
NOTCH FEATURE IN THE 07530Z ENHANCED INFRARED SATELLITE IMAGE AND 
070448Z ATMS MICROWAVE PASS. THE INITIAL INTENSITY IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE PGTW DVORAK ESTIMATE AND REFLECTS
THE 6-HR STRUCTURAL IMPROVEMENT. THE ENVIRONMENT REMAINS HIGHLY
FAVORABLE WITH WARM SST WITH HIGH OHC, STRONG EQUATORWARD OUTFLOW, AND 
LOW VWS.

INITIAL WIND RADII BASIS: PERSISTENCE.

CURRENT STEERING MECHANISM: MID-LEVEL SUBTROPICAL RIDGE (STR) TO
THE NORTHWEST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T1.5 - 25 KTS
   CIMSS SATCON: 41 KTS AT 070358Z
   CIMSS ADT: 37 KTS AT 070250Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 14W WILL BEGIN TO TRACK MORE WEST-
NORTHWESTWARD THEN NORTHWESTWARD AS THE STR TO THE EAST BUILDS
AND ASSUMES STEERING. THE HIGHLY FAVORABLE ENVIRONMENT WILL FUEL A
STEADY THEN RAPID INTENSIFICATION TO A PEAK OF 120KTS BY TAU 72.
AFTERWARD, INCREASING VWS WILL BEGIN TO SLOWLY ERODE THE SYSTEM AND
BY TAU 120 WILL BE DOWN TO 100KTS. AFTER TAU 96, A DEEP MIDLATITUDE
SHORTWAVE TROUGH WILL DIG OVER EASTERN CHINA AND WEAKEN THE STR, 
ALLOWING THE SYSTEM TO TRACK MORE POLEWARD OF NORTHWESTWARD.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GENERAL AGREEMENT BUT
SPREAD OUT SIGNIFICANTLY, ALBEIT EVENLY, TO OVER 400NM BY TAU 120
WITH UEMN ON THE LEFT AND AEMN ON THE RIGHT MARGIN OF THE ENVELOPE.
IN VIEW OF THIS, THERE IS MEDIUM CONFIDENCE IN THE JTWC TRACK
FORECAST THAT IS LAID CLOSE TO THE MODEL CONSENSUS. THERE IS ALSO
MEDIUM CONFIDENCE IN THE JTWC INTENSITY FORECAST.  

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