WDPN32 PGTW 221500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 10W (CEMPAKA) 
WARNING NR 017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.1N 107.9E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 130 NM EAST-NORTHEAST OF HANOI, VIETNAM
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 06 KTS

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
WEAKLY-DEFINED, PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION (LLC) WITH
FLARING DEEP CONVECTION. ANIMATED RADAR IMAGERY INDICATES A
POORLY-DEFINED LLC WITH DISORGANIZED CONVECTION. THE INITIAL
POSITION IS PLACED WITH LOW CONFIDENCE BASED ON EIR SATELLITE
IMAGERY. THE INITIAL INTENSITY OF 25 KTS IS ASSESSED WITH LOW 
CONFIDENCE BASED ON A SLP OBSERVATION OF 1000MB FROM NANNING WUXU 
INTERNATIONAL AIRPORT (ZGNN), WHICH CORRESPONDS TO A TD STRENGTH 
SYSTEM. IN ADDITION TO LAND INTERACTION, UPPER-LEVEL ANALYSIS 
INDICATES MARGINAL CONDITIONS WITH WEAK EQUATORWARD OUTFLOW.

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

CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT BETWEEN
A WEAK SUBTROPICAL RIDGE TO THE NORTH AND EXTENSIVE WESTERLIES TO
THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 15-20 KTS
   SST: 26-27 CELSIUS
   OUTFLOW: WEAK EQUATORWARD
   OTHER FACTORS: FRICTIONAL EFFECTS FROM PROLONGED TRACK OVERLAND

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: LOW
   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 10W CONTINUES TO STRUGGLE OVERLAND WITH
WEAK OVERALL STRUCTURE AND IS EXPECTED TO TURN SOUTHWARD AND
REEMERGE OVER THE GULF OF TONKIN BY TAU 24. AFTER TAU 24, TD 10W
WILL TRACK EASTWARD UNDER THE STEERING INFLUENCE OF THE LOW-LEVEL
WESTERLIES TO THE SOUTH. MINIMAL REINTENSIFICATION TO 30 KNOTS IS
ANTICIPATED BY TAU 24 THEN STEADY WEAKENING AND DISSIPATION BY TAU
48 NEAR HAINAN ISLAND. ENVIRONMENTAL CONDITIONS WILL REMAIN
MARGINAL THROUGH TAU 48 WITH MODERATE TO STRONG VERTICAL WIND SHEAR
AND WEAK OUTFLOW. THERE IS A DISTINCT POSSIBILITY THE SYSTEM MAY
DISSIPATE EARLIER IN THE FORECAST PERIOD.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE SUPPORTS THE JTWC
FORECAST TRACK WITH LOW CONFIDENCE BUT GENERALLY SUPPORTS THE TRACK
PHILOSOPHY. INTENSITY GUIDANCE IS IN POOR AGREEMENT, THEREFORE,
THERE IS LOW CONFIDENCE IN THE JTWC INTENSITY FORECAST.

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