WDPN31 PGTW 060300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 03W (THREE) 
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.4N 134.8E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 304 NM NORTHWEST OF YAP
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A LARGE (500+
NM ACROSS), SLOWLY CONSOLIDATING SYSTEM WITH A BROAD, ELONGATED LOW
LEVEL CIRCULATION (LLC) AND EXPANSIVE, FRAGMENTED, FORMATIVE BANDS
SPIRALING IN FROM ALL QUADRANTS. THE INITIAL POSITION IS PLACED
WITH MEDIUM CONFIDENCE BASED ON LOW CLOUD LINE TRACING INTO AN
OBSCURED LLC. THE INITIAL INTENSITY OF 25KTS IS BASED ON THE HIGH
END OF AGENCY DVORAK ESTIMATES AND REFLECTS THE 6-HR IMPROVED
CONVECTIVE SIGNATURE AND WRAP. ANALYSIS INDICATES A FAVORABLE
ENVIRONMENT WITH LOW VWS, MODERATE EQUATORWARD OUTFLOW, AND WARM
SST IN THE PHILIPPINE SEA.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: AN EXTENSION OF A LOW REFLECTION OF THE
SUBTROPICAL RIDGE (STR) TO THE NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.0 - 25 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T1.0 - 25 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TD 03W IS EXPECTED TO CONTINUE ON ITS CURRENT
TRACK, THEN AFTER TAU 12, TURN NORTHWESTWARD UNDER THE STEERING
INFLUENCE OF THE STR. AFTER TAU 72, IT WILL VEER MORE NORTHWARD AS
IT BEGINS TO ROUND THE STR AXIS. THE FAVORABLE CONDITIONS WILL FUEL
A GRADUAL INTENSIFICATION, REACHING 85KTS BY TAU 120.    

MODEL DISCUSSION: NUMERICAL MODELS, ALTHOUGH IN GENERAL AGREEMENT,
SPREAD OUT CONSIDERABLY, ALBEIT EVENLY, TO 180 NM AT TAU 72, THEN
TO 320 NM AT TAU 120. THERE IS ALSO SOME ALONG-TRACK DIFFERENCES
AMONG THE MEMBERS. IN VIEW OF THESE, PLUS GIVEN THE TRACK
UNCERTAINTIES TYPICAL WITH DEVELOPING SYSTEMS, THERE IS LOW
CONFIDENCE IN THE JTWC TRACK AND INTENSITY FORECASTS UP TO TAU 12O.

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