WDPN33 PGTW 280900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (CO-MAY) WARNING NR 
022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.6N 128.3E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 27 NM EAST-NORTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH SHALLOW CURVED
BANDING WRAPPING INTO THE CENTER OF TROPICAL STORM (TS) 11W.
TROCHOIDAL MOTION IS EVIDENT AS THE SYSTEM TRACKED NORTHWESTWARD
CYCLONICALLY WHILE WEAKLY STEERED ALONG THE SUBTROPICAL RIDGE
CENTERED OVER JAPAN. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE AFOREMENTIONED ANIMATED VISIBLE IMAGERY AND
RADAR IMAGERY REVEALING WEAK CURVED BANDING EAST OF THE LLCC. THE
INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON THE AGENCY AND OBJECTIVE FIXES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: A SUBTROPICAL RIDGE TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.5 - 35 KTS
   KNES: T2.0 - 30 KTS
   CIMSS SATCON: 39 KTS AT 280420Z
   CIMSS ADT: 26 KTS AT 280530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK EQUATORWARD

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: TS 11W WILL CONTINUE TO MEANDER
WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF A SUBTROPICAL
RIDGE TO THE NORTH. THE SYSTEM WILL CONTINUE TO ROUND THE SOUTHERN
PERIPHERY OF THE RIDGE AND ASSUME A NORTHWESTWARD TRACK FOLLOWING
TAU 36. THE SYSTEM WILL MAKE LANDFALL BETWEEN TAU 48-72 AND WEAKLY
TRACK NORTH-NORTHWESTWARD FOR THE REMAINDER OF THE FORECAST.
SIGNIFICANT DRY AIR ASSOCIATED WITH AN UPPER-LEVEL CYCLONE TO THE
NORTHWEST CONTINUES TO ATROPHY THE VERTICAL EXTENT OF TS 11. AS THE
UPPER-LEVEL CYCLONE WILL MOVE SOUTHWESTWARD AWAY FROM THE
CIRCULATION, ALLOWING FOR WEAK AND GRADUAL INTENSIFICATION TO A
PEAK OF 45 WITHIN THE NEXT 48 HOURS. AFTER TAU 48, SLIGHT UPWELLING
OFFSHORE AT TAU 36 WILL INITIATE A WEAKENING PHASE AS THE SYSTEM
APPROACHES THE CHINA COAST. TS 11W WILL MAKE LANDFALL BETWEEN TAU
48-72, INCREASING THE WEAKENING TREND UNTIL THE SYSTEM DISSIPATES
OVER LAND.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 24 WITH A 60NM CROSS-TRACK SPREAD. THE JTWC MULTI-MODEL
CONSENSUS SOLUTIONS BEGIN TO SPREAD AFTER TAU 24. THE CROSS-TRACK
SPREAD AT TAU 120 IS 360NM, WITH GALWEM TO THE WEST OVER
LAND AND NAVGEM TO THE EAST OVER OPEN OCEAN FOR THE ENTIRETY OF THE
TRACK SOLUTION. THE FORECAST LIES CLOSELY TO GFS, GEFS, UKMET, AND
JGSM OVER LAND, BUT ENSEMBLE SOLUTIONS WITHIN COAMPS-TC ENSEMBLE,
GEFS, AND ECENS REVEAL THAT THE SYSTEM MAY REMAIN OVER WATER. EVEN
SO, AN UNFAVORABLE TROUGH OVER THE YELLOW SEA IS LIKELY TO
DISCOURAGE DEVELOPMENT OVER WATER. THE INTENSITY GUIDANCE IS IN
GENERAL AGREEMENT THAT THE SYSTEM WILL REACH A PEAK INTENSITY
BETWEEN 40-50KTS BETWEEN TAU 36-48.

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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