WDPN31 PGTW 291500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 14W (FOURTEEN) 
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.5N 134.2E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 917 NM SOUTHEAST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: WESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED PROXYVIS SATELLITE IMAGERY (PSI) DEPICTS TROPICAL
DEPRESSION 14W (FOURTEEN) GRADUALLY DEVELOPING AND TRACKING
WESTWARD AT APPROXIMATELY 6 KTS OVER THE PAST SIX HOURS. DEEP,
PERSISTENT CONVECTION IS OBSERVED ALONG THE SOUTHWESTERN PERIPHERY
OF A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THIN,
WISPY CIRRUS ARE OBSERVED FLOWING WEAKLY POLEWARD AND EQUATORWARD
ALOFT. A 290859Z SSMIS 91GHZ MICROWAVE IMAGE SHOWS SHALLOW CLOUD
BANDING WRAPPING INTO THE LLCC WITH FAIRLY BROAD OUTREACH, UP TO
370NM OUT FROM THE CENTER OF CIRCULATION. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON A 291200Z CIRA-PROXYVIS 2KM
IMAGE. THE INITIAL INTENSITY OF 25 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON EXTRAPOLATION OF A 290852Z SMOS WIND SPEED IMAGE
AND A 291216Z PARTIAL PASS ASCAT-C SCATTEROMETRY IMAGE.

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

CURRENT STEERING MECHANISM: EXTENSION OF SUBTROPICAL RIDGE TO THE
NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: WEAK POLEWARD AND 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: OVER THE NEXT 72 TO 96 HOURS, TROPICAL
DEPRESSION 14W (FOURTEEN) IS FORECAST TO TRACK ON A NORTHWESTWARD
TRAJECTORY AND GRADUALLY INTENSIFY.  FAVORABLE SEA SURFACE 
TEMPERATURES AND OCEAN HEAT CONTENT ARE OFFSET BY DRY AIR (BELOW 50 
PERCENT RELATIVE HUMIDITY) AND SIGNIFICANT SHEAR IN THE UPPER LAYERS. 
BETWEEN TAU 72 AND 96, SHEAR IS FORECAST TO REDUCE AND THE
ENVIRONMENT BECOMES MORE MOIST, ALLOWING FOR QUICKER (POSSIBLY
RAPID) INTENSIFICATION TO OCCUR. THE FORECAST CONFIDENCE OF BOTH
TRACK AND INTENSITY IS MEDIUM THROUGH TAU 72, AND DUE TO THE
BIFURCATED MODEL GUIDANCE DISCUSSED BELOW, LOW THEREAFTER.

MODEL DISCUSSION: GLOBAL NUMERICAL ENSEMBLE AND DETERMINISTIC
GUIDANCE HAS BECOME MUCH BETTER ALIGNED FROM THE 00Z MODEL GUIDANCE
TO THE 06Z MODEL GUIDANCE.  HOWEVER, THERE IS STILL BIFURCATION
AMONG THE SOLUTIONS OFFERED.  NAVGEM, COAMPS, AND THE BULK OF GFS
ENSEMBLE MEMBERS TRACK THE SYSTEM TURNING TO MORE OF A NORTHWARD
TRAJECTORY OVER TIME ROUNDING THE SUBTROPICAL RIDGE TO THE EAST. 
THE BULK OF JTWC CONSENSUS MEMBERS AND OTHER MODEL GUIDANCE, HOWEVER, 
TRACK THE SYSTEM NORTHWEST AND AROUND TAU 72 TO TAU 96 TURN THE TRACK 
MORE WESTWARD.

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