WDPN32 PGTW 071500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (TAPAH) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.0N 113.6E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 142 NM SOUTH-SOUTHWEST OF HONG KONG
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 21 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
CONSOLIDATING LOW-LEVEL CIRCULATION (LLC), WITH DEEP CONVECTION
BUILDING OVER THE CENTER. ANIMATED RADAR IMAGERY REVEALS A PARTIAL
EYEWALL OVER THE EASTERN QUADRANT, WITH A POSSIBLE DEVELOPING EYE.
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE
EIR AND RADAR IMAGERY. BASED ON THE STEADY CONSOLIDATION, CIMSS
OBJECTIVE INTENSITY ESTIMATES HAVE INCREASED AND NOW RANGE FROM
42-49 KNOTS. THE INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH MEDIUM 
CONFIDENCE, HEDGED SLIGHTLY ABOVE THE AGENCY DVORAK ESTIMATES BASED 
ON THE IMPROVING CORE STRUCTURE. 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.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

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
   KNES: T3.0 - 45 KTS
   DEMS: T3.0 - 45 KTS
   CIMSS ADT: 47 KTS AT 071130Z
   CIMSS AIDT: 43 KTS AT 071130Z
   CIMSS D-PRINT: 56 KTS AT 071230Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 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: TROPICAL STORM (TS) 22W IS FORECAST TO CONTINUE 
TO STEADILY MOISTEN AND WILL CONSOLIDATE QUICKLY OVER THE NEXT 12 
HOURS AS IT APPROACHES THE SOUTHERN COAST OF CHINA. A PEAK INTENSITY 
OF 65-70 KNOTS WILL OCCUR AROUND TAU 12 JUST PRIOR TO LANDFALL. AFTER 
TAU 12, 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 12, WITH A 22NM CROSS-TRACK SPREAD AT TAU 12. AFTER TAU
12, GUIDANCE DIVERGES WITH INCREASING UNCERTAINTY OVERLAND. THE
LATEST EPS AND GEFS ENSEMBLES SHOW A SIMILAR SPREAD SUPPORTING THE
JTWC TRACK FORECAST WITH MEDIUM CONFIDENCE. RELIABLE INTENSITY
GUIDANCE IS FAIRLY FLAT THROUGH TAU 12. HOWEVER, THE 070600Z HAFS-A
RAW OUTPUT INDICATES SIGNIFICANT CONSOLIDATION AND A PEAK INTENSITY
OF 58.7 KNOTS AT 072100Z JUST PRIOR TO LANDFALL. 

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