WDPN31 PGTW 250300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (ONE)     
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.3N 124.1E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 228 NM SOUTHEAST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 8 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY INDICATES A CONSOLIDATING 
SYSTEM WITH IMPROVED CONVECTIVE BANDING WRAPPING INTO A SMALL CENTRAL 
DENSE OVERCAST FEATURE, WHICH IS OBSCURING THE LOW-LEVEL CIRCULATION 
CENTER (LLCC). A 242118Z SSMIS 91 GHZ PCT MICROWAVE IMAGE ALSO REVEALS 
THE IMPROVED CURVED BANDING OVER THE NORTHERN SEMICIRCLE WRAPPING INTO 
THE CORE AND GENERALLY SUPPORTS THE INITIAL POSITION. ANIMATED RADAR 
IMAGERY DEPICTS BROAD CYCLONIC TURNING BUT DOES NOT SHOW A DEFINED 
CENTER. THEREFORE, THERE IS MEDIUM CONFIDENCE IN THE INITIAL POSITION. 
THE INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE 
RJTD DVORAK ESTIMATE AND THE IMPROVED CONVECTIVE STRUCTURE. DUE TO 
INTERACTION WITH LAND AND FRICTIONAL EFFECTS, THE OVERALL ENVIRONMENT 
IS ASSESSED AS MARGINALLY FAVORABLE, HOWEVER, THE UPPER-LEVEL OUTFLOW 
IS NEAR-RADIAL WITH LOW VERTICAL WIND SHEAR (VWS).

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

CURRENT STEERING MECHANISM: LOW-LEVEL SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTH AND NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   RJTD: T2.0 - 30 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 0-5 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL DEPRESSION (TD) 01W IS FORECAST TO
TRACK NORTHWESTWARD THROUGH TAU 24 THEN TURN SHARPLY POLEWARD AND
SLOW AS THE WESTERN EXTENT OF THE STR WEAKENS DUE TO SUBTROPICAL
WESTERLIES SHIFTING INTO THE SOUTH CHINA SEA. AFTER THE SYSTEM
RE-EMERGES OVER WATER EAST OF LUZON AND TRACKS AWAY FROM LAND, IT
IS FORECAST TO INTENSIFY STEADILY. AFTER TAU 36, THE SYSTEM WILL
TRACK ALONG THE WESTERN PERIPHERY OF A DEEP-LAYERED STR ENTRENCHED
OVER THE EAST PHILIPPINE SEA. THE SYSTEM WILL LIKELY EXPERIENCE
ENHANCED POLEWARD OUTFLOW, LEADING TO A FASTER INTENSIFICATION RATE
THROUGH TAU 72. AFTER TAU 72, THE SYSTEM WILL INTERACT WITH THE
SUBTROPICAL WESTERLIES AND INCREASING VWS (35 KNOTS), WHICH WILL
LEAD TO A WEAKENING TREND. BY TAU 120, THE SYSTEM WILL INTERACT
WITH THE BAROCLINIC ZONE AND COMMENCE EXTRA-TROPICAL TRANSITION
(ETT), WITH STRONG VWS OF 50-55 KNOTS. THE SYSTEM IS HIGHLY UNLIKELY 
TO IMPACT MAINLAND JAPAN DUE TO THE PRESENCE OF A STRONG JET THROUGH 
THE EXTENDED FORECAST PERIOD.   

MODEL DISCUSSION: WITH THE EXCEPTION OF GALWEM (AFUM), NUMERICAL
MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 72 WITH AN 85 NM
CROSS-TRACK SPREAD AT TAU 72. AFTER TAU 72, THE DETERMINISTIC MODEL
TRACKERS DIVERGE ALONG-TRACK WITH INCREASING UNCERTAINTY. THE COAMPS-
TC INTENSITY PROBABILITY PRODUCT INDICATES A MODERATE PROBABILITY (40-
50 PERCENT) OF RAPID INTENSIFICATION FROM TAU 30 TO TAU 84. THE GEFS 
AND EPS ENSEMBLES INDICATE INCREASING UNCERTAINTY NEAR TAU 24 WHEN THE 
SYSTEM IS EXPECTED TO TURN SHARPLY POLEWARD, WITH THE BULK OF THE 
SOLUTIONS EAST OF LUZON. AFTER TAU 24, THE BULK OF THE PROBABILISTIC 
GUIDANCE SUPPORTS THE JTWC FORECAST TRACK WITH MEDIUM CONFIDENCE.      

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