WDPN32 PGTW 070900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (TAPAH) WARNING NR 
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.3N 113.8E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 181 NM SOUTH OF HONG KONG
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY-
EXPOSED LOW-LEVEL CIRCULATION (LLC), WITH DEEP CONVECTION BUILDING 
OVER AND OBSCURING THE CENTER. A 070530Z GMI 89GHZ COLOR COMPOSITE 
MICROWAVE IMAGE REVEALS SHALLOW BANDING WRAPPING INTO A WELL-DEFINED 
LOW-LEVEL CIRCULATION CENTER, WITH CURVED DEEP CONVECTIVE BANDING 
OVER THE SOUTHERN SEMICIRCLE. THE INITIAL POSITION IS PLACED WITH 
HIGH CONFIDENCE BASED ON THE MSI AND GMI IMAGE. THE INITIAL INTENSITY 
OF 45 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON AGENCY DVORAK 
ESTIMATES AND RECENT ASCAT-C DATA. CIMSS OBJECTIVE ESTIMATES RANGE 
FROM 34-45 KNOTS. ENVIRONMENTAL CONDITIONS HAVE STEADILY IMPROVED 
OVER THE PAST 12 HOURS, WITH PERSISTENT STRONG EQUATORWARD OUTFLOW, 
EXPANDING NORTHWARD OUTFLOW, LOW VERTICAL WIND SHEAR AND WARM SST 
VALUES. THE ONLY LIMITATION AT THIS TIME IS DRY AIR OVER THE WESTERN 
QUADRANT.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE EAST AND NORTHEAST, WITH A WEAK RIDGE EXTENSION
TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 44 KTS AT 070513Z
   CIMSS ADT: 45 KTS AT 070530Z
   CIMSS AIDT: 38 KTS AT 070530Z
   CIMSS D-MINT: 36 KTS AT 070528Z
   CIMSS D-PRINT: 34 KTS AT 070530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD
   OTHER FACTORS: DRY AIR OVER THE WESTERN QUADRANT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TROPICAL STORM (TS) 22W WILL MOISTEN AND 
CONSOLIDATE QUICKLY OVER THE NEXT 18 HOURS AS IT APPROACHES THE
SOUTHERN COAST OF CHINA. A PEAK INTENSITY OF 65-70 KNOTS WILL OCCUR
AROUND TAU 18 JUST PRIOR TO LANDFALL. AFTER TAU 18, THE SYSTEM WILL
GRADUALLY TURN WEST-NORTHWESTWARD TO WESTWARD AS IT STEERS UNDER
THE BUILDING STR TO THE NORTH. DISSIPATION IS EXPECTED BY TAU 48.  

MODEL DISCUSSION: DETERMINISTIC GUIDANCE REMAINS IN GOOD AGREEMENT
THROUGH TAU 24, WITH A 50NM CROSS-TRACK SPREAD AT TAU 24. AFTER TAU
24, GUIDANCE DIVERGES WITH INCREASING UNCERTAINTY OVERLAND. THE
LATEST EPS AND GEFS ENSEMBLES SHOWS A SIMILAR SPREAD SUPPORTING THE
JTWC TRACK FORECAST WITH MEDIUM CONFIDENCE. WITH THE EXCEPTION OF
HWRF, WHICH PEAKS THE INTENSITY AT 58 KNOTS AT TAU 12, RELIABLE
INTENSITY GUIDANCE IS FAIRLY FLAT THROUGH TAU 12. HOWEVER, THE
070000Z HAFS-A RAW OUTPUT INDICATES SIGNIFICANT CONSOLIDATION AND A
PEAK INTENSITY OF 63.7 KNOTS AT 072100Z JUST PRIOR TO LANDFALL.    
   

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM//
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