WDPN31 PGTW 150300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 03W (THREE) WARNING 
NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.1N 109.8E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 87 NM EAST OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A CONTINUING
RAGGED AND ILL-DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC). THE
LOW-LEVEL CIRCULATION HAS REMAINED FULLY-EXPOSED OVER THE PREVIOUS
SIX HOURS WHILE EMBEDDED MESOVORTICES HAVE BEGUN WRAPPING AROUND
THE NORTHERN QUADRANT OF THE LLCC. THE PRIMARY CONVECTIVE
STRUCTURES ASSOCIATED WITH TD 03W CONTINUE TO FLARE AROUND THE
NORTHWESTERN PERIPHERY IN CLOSE PROXIMITY TO THE VIETNAMESE
COASTLINE. A 141823Z AMSR2 WINDSPEED IMAGE REVEALED ISOLATED AREAS
OF 20-25 KNOT WINDS ALONG THE NORTHWESTERN AND SOUTHERN QUADRANTS
OF TD 03W, WHILE THE AVERAGE INTENSITIES AROUND THE SYSTEM HAVE
REMAINED LARGELY BETWEEN 10-15 KNOTS. COASTAL SURFACE OBSERVATIONS
HAVE ALSO INDICATED AVERAGE WINDS BETWEEN 0-10 KNOTS, WITH MINIMUM
SLP VALUES RANGING BETWEEN 1002 MB AND 1004 MB. SHIP SURFACE
OBSERVATIONS HAVE BEEN REPORTING ENHANCED INTENSITIES BETWEEN 24-27
KNOTS 60 NM SOUTHEAST FROM THE ASSESSED LLCC. THE OVERALL ENVIRONMENT 
IS ASSESSED AS UNFAVORABLE DUE TO CONTINUED STRONG VERTICAL WIND 
SHEAR
(VWS) (25-30 KNOTS) AND WEAK UPPER-LEVEL OUTFLOW MECHANISMS. THE
INITIAL POSITION IS PLACED WITH LOW CONFIDENCE DUE TO A BROADENING
AND RAGGED SURFACE CIRCULATION ILLUSTRATED ON ANIMATED MSI AND
VISIBLE IMAGERY. THE INITIAL INTENSITY OF 25 KNOTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE AFOREMENTIONED AMSR2 PASS AND ON THE
SUBJECTIVE AGENCY FIX LISTED BELOW.

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

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

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

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 25-30 KTS
   SST: 28-30 CELSIUS
   OUTFLOW: WEAK EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: MEDIUM
   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: TD 03W IS FORECAST TO TRACK WEST-NORTHWEST
ALONG THE SOUTHWESTERN AXIS OF THE STR THROUGH TAU 12 AND BEGIN
DISSIPATING WITH INCREASED FRICTIONAL INFLUENCES AS THE SYSTEM
MOVES ONSHORE. AFTER TAU 12, THE TROPICAL DEPRESSION WILL CONTINUE
PROGRESSING WESTWARD OVER THE RUGGED TERRAIN OF VIETNAM AND
CONTINUE WEAKENING THROUGH THE END OF THE FORECAST PERIOD. AS TD
03W MOVES ONSHORE SOON AFTER TAU 12, THE SYSTEM IS ANTICIPATED TO
RAPIDLY DECAY DUE TO CONTINUED STRONG VWS (25-30 KNOTS), INCREASED
FRICTION FROM THE MOUNTAINOUS TERRAIN OF VIETNAM, AND A LOSS OF
SUPPORTIVE CONVECTIVE STRUCTURES. BY TAU 36, TD 03W IS FORECASTED
TO COMPLETE DISSIPATION OVER LAND.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT
THROUGH TAU 36 WITH A 60 NM CROSS-TRACK SPREAD AT COMPLETE
DISSIPATION. THE DETERMINISTIC MODEL TRACKERS REMAIN IN ALIGNMENT
THAT A WEST-NORTHWEST TRACK INTO LANDFALL IS EXPECTED WITH HIGH
CONFIDENCE. THE COAMPS-TC INTENSITY PROBABILITY PRODUCT INDICATES A
LOW PROBABILITY (10-20 PERCENT) OF STEADY TO MODERATE
INTENSIFICATION THROUGH ITS CONTINUED WESTWARD TRACK THROUGH TAU
12, AND MODERATE WEAKENING INTO THE END OF THE FORECAST PERIOD (TAU
36). THE CURRENT JTWC FORECAST LIES NEAR THE MULTI-MODEL CONSENSUS
WITH HIGH CONFIDENCE THROUGH TAU 36. 

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