WDPN31 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 18W (CONSON) WARNING NR 
014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.0N 117.1E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 241 NM WEST-NORTHWEST OF MANILA,
PHILIPPINES
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A
DISORGANIZED SYSTEM WITH A LARGE FRAGMENTED BAND OF CONVECTION TO 
THE WEST OF THE SYSTEM CENTER. THE INITIAL POSITION IS BASED ON 
UPPER-LEVEL BANDING IN A 090515Z 89GHZ AMSR2 IMAGE AND THE INITIAL 
INTENSITY IS BASED ON THE AMSR2 WINDSPEED PRODUCT FOR THE SAME TIME 
SHOWING A CIRCULATION OF MOSTLY 40-45 KT WINDS WITH A PATCH OF 50 KT 
WINDS IN THE NORTHEAST QUADRANT.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WEAK STEERING ENVIRONMENT.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 45 KTS AT 090453Z
   CIMSS ADT: 47 KTS AT 090600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL STORM (TS) 18W BEGIN TO TRACK
WESTWARD IN A WEAK STEERING ENVIRONMENT. AROUND TAU 48, IT WILL
TURN MORE WEST-NORTHWESTWARD AS A MID-LATITUDE TROUGH BEGINS TO 
DEEPEN TO THE NORTH. THE SYSTEM IS EXPECTED TO MAKE LANDFALL OVER 
NORTHERN VIETNAM ROUGHLY 80 NM SOUTH OF HANOI. THE MARGINALLY 
FAVORABLE ENVIRONMENT WILL ALLOW A SLIGHT INTENSIFICATION TO A PEAK 
OF 70KTS AROUND TAUS 48. AFTERWARD, LAND INTERACTION WITH HAINAN AND 
LANDFALL OVER VIETNAM JUST BEFORE TAU 120 WILL RAPIDLY ERODE THE 
SYSTEM DOWN TO 25 KTS. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN POOR AGREEMENT, WITH AFUM
AND NVGM TRACKING THE SYSTEM DIRECTLY NORTHWARD AT TAUS 12 AND 24,
RESPECTIVELY. OTHER MODELS TRACK THE SYSTEM GENERALLY WESTWARD, BUT
PROVIDE A WIDE RANGE OF POSSIBLE LANDFALL LOCATION. INTENSITY
GUIDANCE IS IN FAIR AGREEMENT, WILL ALL MODELS SHOWING AN
INTENSIFICATION PHASE PEAKING AT ABOUT 70 KTS AROUND TAU 48,FOLLOWED 
BY A STEADY WEAKENING TREND.   

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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