WDPN31 PGTW 142100
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: 15.4N 110.4E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 127 NM EAST-SOUTHEAST OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS AN
ILL-DEFINED FULLY-EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC). THE
MAJORITY OF ASSOCIATED CONVECTION REMAINS DISORGANIZED AND ISOLATED
THROUGHOUT THE WESTERN PERIPHERY OF THE LOW-LEVEL CIRCULATION ALONG
THE COASTLINE OF VIETNAM. A 141419Z ASCAT-C IMAGE REVEALED A BROAD
CIRCULATION WITH A SMALL SWATH OF 25 KNOT WINDS BETWEEN 65-70NM TO
THE NORTHEAST OF THE ASSESSED CIRCULATION CENTER, HOWEVER, THE
CENTER IS FLANKED BY LARGE AREAS OF 20 KNOT SWATHS THROUGHOUT THE
WESTERN AND NORTHEASTERN QUADRANTS. COASTAL AND SHIP SURFACE
OBSERVATIONS INDICATED AVERAGE WINDS BETWEEN 13-18 KNOTS, WITH A
MINIMUM SLP VALUE RANGING BETWEEN 1000 MB TO 1002 MB. THE OVERALL
ENVIRONMENT IS ASSESSED AS UNFAVORABLE DUE TO 25-30 KNOT VERTICAL
WIND SHEAR (VWS) AND IMPENDING FRICTIONAL EFFECTS DUE TO
INTERACTION WITH COASTAL VIETNAM OVER THE NEXT 12 TO 24 HOURS. THE
CURRENT AND ONLY AGENCY DVORAK INTENSITY ESTIMATE FROM RJTD IS
T0.5.

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: NO CURRENT ESTIMATE

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

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL DEPRESSION (TD) 03W IS FORECAST TO
TRACK WEST-NORTHWESTWARD ALONG THE SOUTHWESTERN EDGE OF THE WELL-
ESTABLISHED SUBTROPICAL RIDGE THROUGH TAU 12 AND DISSIPATE OVER 
VIETNAM AND LAOS BETWEEN TAU 24 AND TAU 36, RESPECTIVELY. AS TD 03W 
CONTINUES WESTWARD, THE SYSTEM IS ANTICIPATED TO REMAIN 25 KNOTS 
THROUGH A HARSH ENVIRONMENT OF STRONG VWS BETWEEN 25-30 KNOTS. BETWEEN 
TAU 12 AND TAU 24, TD 03W IS EXPECTED TO MAKE LANDFALL AND BEGIN ITS
DISSIPATION PHASE DUE TO INCREASED FRICTIONAL INFLUENCES AND
SUSTAINED DESTRUCTIVE VWS AS SUPPORTIVE UPPER-LEVEL OUTFLOW REMAINS
MINIMAL FOR ANY FURTHER INTENSIFICATION. BY TAU 36, TD 03W IS
FORECASTED TO COMPLETE DISSIPATION OVER LAND.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN VERY STRONG
AGREEMENT THROUGH TAU 36 WITH A 55 NM CROSS-TRACK SPREAD AT THE END
OF THE FORECAST PERIOD. THE DETERMINISTIC MODEL TRACKERS CONTINUE
TO ALIGN WITH AN EXPECTED WEST-NORTHWEST MOVEMENT INTO LANDFALL
WITH VERY HIGH CONFIDENCE. THE COAMPS-TC INTENSITY PROBABILITY
PRODUCT INDICATES A LOW PROBABILITY (10-20 PERCENT) OF STEADY TO
MODERATE INTENSIFICATION BEFORE LANDFALL. THE GEFS AND EPS
ENSEMBLES ILLUSTRATE CONTINUED TROPICAL DEPRESSION STRENGTH
INTENSITIES AS WELL (25-34 KNOTS) BEFORE SUSTAINED STRONG VWS
(25-30 KNOTS) AND INCREASED LAND INTERACTION BEGINS TO DISSIPATE TD
03W.

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