WDPN32 PGTW 072100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (TAPAH) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.8N 113.2E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 106 NM SOUTH-SOUTHWEST OF HONG KONG
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 27 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL STORM (TS) 22W HAS UNDERGONE A PERIOD OF RAPID
AXISYMMETRIZATION AND INTENSIFICATION OVER THE LAST SIX TO EIGHT HOURS 
AS IT APPROACHES THE CHINESE COAST. ANIMATED ENHANCED INFRARED (EIR) 
SATELLITE IMAGERY DEPICTS A SIGNIFICANT IMPROVEMENT IN THE OVERALL 
STRUCTURE OF THE SYSTEM, WITH A SMALL CENTRAL DENSE OVERCAST (CDO) 
DEVELOPING AROUND 1400Z AND WHICH HAS CONTINUED TO STEADILY IMPROVE 
THROUGH 1800Z. ANIMATED RADAR IMAGERY FROM CHINA DEPICTS A
WELL-DEFINED RADAR EYE WITH DEEP CONVECTION FORMING A SOLID EYEWALL
THAT EXTENDS FROM WEST OF THE CENTER THROUGH THE NORTHEASTERN SECTOR. 
COMPARISON BETWEEN THE RADAR AND THE EIR SUGGESTS SOME RESIDUAL 
WESTWARD VORTEX TILT MAY REMAIN, SUPPORTED BY THE CIMSS SHEAR 
ANALYSIS, CURRENTLY INDICATING A SHEAR VECTOR OF 080 DEG AT 11 KNOTS. 
HOWEVER, THE AMOUNT OF TILT HAS DECREASED SINCE YESTERDAY, AND THE 
SYSTEM HAS INTENSIFIED ABOUT 15 KNOTS IN THE LAST 12 HOURS. THE 
INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE RADAR 
DATA DISCUSSED ABOVE. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM 
CONFIDENCE, HEDGED SLIGHTLY HIGHER THAN THE SUBJECTIVE AND OBJECTIVE 
FIX ESTIMATES BELOW BASED ON THE RAPIDLY IMPROVING STRUCTURE AND 
APPEARANCE AS WELL AS SLIGHTLY HIGHER RAW ADT VALUES. ENVIRONMENTAL 
CONDITIONS REMAIN FAVORABLE, WITH LOW VWS, WARM SSTS AND MODERATE 
DUAL-CHANNEL OUTFLOW ALOFT.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T3.0 - 45 KTS
   CIMSS SATCON: 53 KTS AT 071743Z
   CIMSS ADT: 55 KTS AT 071730Z
   CIMSS AIDT: 45 KTS AT 071730Z
   CIMSS D-MINT: 53 KTS AT 071743Z
   CIMSS D-PRINT: 46 KTS AT 071800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL STORM (TS) 22W CONTINUES TO TRACK
NORTH-NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE DEEP STR 
TO THE NORTHEAST. LANDFALL IS EXPECTED WITHIN THE NEXT SIX HOURS OR SO 
IN THE VICINITY OF SHANGCHUAN DAO. AFTER LANDFALL, THE SYSTEM WILL 
CONTINUE TO TRACK NORTHWESTWARD, FURTHER INTO SOUTH-CENTRAL CHINA. A 
BRIEF WINDOW FOR ADDITIONAL INTENSIFICATION EXISTS PRIOR LANDFALL AND 
IT IS EXPECTED TO REACH A PEAK INTENSITY OF 65-70 KNOTS BEFORE 
CROSSING THE COASTLINE. AFTER LANDFALL, THE SYSTEM WILL RAPIDLY WEAKEN 
AND SUBSEQUENTLY DISSIPATE WITHIN THE NEXT 36 HOURS.   

MODEL DISCUSSION: DETERMINISTIC, ENSEMBLE AND ARTIFICIAL
INTELLIGENCE (AI) MODELS ARE IN STRONG AGREEMENT, WITH MINIMAL CROSS- 
OR ALONG-TRACK SPREAD THROUGHOUT THE FORECAST PERIOD. THE JTWC 
FORECAST IS POSITIONED NEAR THE MULTI-MODEL CONSENSUS MEAN WITH HIGH 
CONFIDENCE. NEITHER THE JTWC FORECAST POINTS NOR THE MODEL GUIDANCE 
POSSESS SUFFICIENT TEMPORAL RESOLUTION TO CAPTURE THE BRIEF 
INTENSIFICATION PERIOD PRIOR TO LANDFALL. NEVERTHELESS, THE INTENSITY 
GUIDANCE IS IN GOOD AGREEMENT THAT, SUBSEQUENT TO LANDFALL, THE SYSTEM 
WILL RAPIDLY WEAKEN AND DISSIPATE OVER LAND WITHIN THE NEXT 36 HOURS.

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