WDPN31 PGTW 161500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 04W (TALIM)        
WARNING NR 009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.7N 114.9E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 161 NM SOUTH-SOUTHEAST OF HONG KONG
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 26 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL STORM (TS) 04W HAS INTENSIFIED SLIGHTLY OVER THE PAST
SIX HOURS. ANIMATED PROXYVIS SATELLITE IMAGERY DEPICTS AN AREA OF
DEEP CONVECTION WITH BANDING IN ALL QUADRANTS WRAPPING INTO AN
OBSCURED, WELL-DEVELOPED LOW LEVEL CIRCULATION CENTER (LLCC). A
161051Z SSMIS 91GHZ MICROWAVE IMAGE SHOWS EXTENSIVE SPIRAL BANDING
FEEDING INTO THE LLCC THROUGHOUT THE SOUTHERN SEMICIRCLE WITH
WEAKER, FRAGMENTED BANDING IN THE NORTHERN PERIPHERY DUE TO THE
SLIGHT DRY AIR ENTRAINMENT IN THE MIDDLE TO UPPER ATMOSPHERE. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE
AFOREMENTIONED SSMIS MICROWAVE IMAGE. A FAVORABLE ENVIRONMENT IS
EVIDENCED BY CONTINUED ROBUST EQUATORWARD OUTFLOW AND AN OVERALL
MORE ORGANIZED STRUCTURE OF 04W OVER THE LAST SIX HOURS. THE
INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH MEDIUM CONFIDENCE AND
IS HEDGED ABOVE THE PGTW, RJTD, KNES DVORAK ESTIMATES BASED ON A
161150Z AIDT ESTIMATE OF 58 KNOTS AND A 160958Z SMAP IMAGE SHOWING 57 
KNOT MAXIMUM WINDS (61 KNOTS CONVERTED TO 1-MINUTE AVERAGE).

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK.

CURRENT STEERING MECHANISM: DEEP LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTH AND NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 47 KTS AT 161150Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 04W IS FORECAST TO TRACK WEST-NORTHWESTWARD
THROUGH TAU 72 UNDER THE STEERING INFLUENCE OF THE STR POSITIONED
TO THE NORTH. HIGH SSTS AND A MOIST ENVIRONMENT WILL CONTRIBUTE TO
INTENSIFICATION THROUGH TAU 24, AT WHICH POINT 04W WILL BEGIN
EXPERIENCING FRICTIONAL EFFECTS FROM THE NORTHERN SHORELINE OF THE
SOUTH CHINA SEA AND LEIZHOU PENINSULA. AFTER A SHORT TRACK OVER
NORTHERN GULF OF TONKIN, THE SYSTEM WILL RAPIDLY DISSIPATE OVER THE
MOUNTAINOUS TERRAIN OF NORTHERN VIETNAM.

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, WHICH TRACKS THE
SYSTEM WESTWARD, THE BULK OF THE NUMERICAL MODEL GUIDANCE IS IN
GOOD AGREEMENT WITH A CROSS TRACK SPREAD OF 95NM AT TAU 48.
RELIABLE INTENSITY GUIDANCE INDICATES A WIDE SPREAD OF PEAK
INTENSITIES AT TAU 24 FROM 60 TO 75 KNOTS. THE 160000Z COAMPS-TC
INTENSITY ENSEMBLE CONTINUES TO INDICATE A PEAK 40 PERCENT
PROBABILITY OF RAPID INTENSIFICATION OCCURRING OVER THE NEXT 12
HOURS DECREASING TO 10 PERCENT PROBABILITY AFTER TAU 12.

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