WDPN33 PGTW 270300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 11W (CO-MAY)  
WARNING NR 017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.6N 127.8E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 6 NM NORTH OF KADENA AB
   MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 13 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY 
EXPOSED LOW-LEVEL CIRCULATION (LLC), WITH IMPROVED CONVECTIVE BANDING 
OVER THE SOUTHERN SEMICIRCLE. ANIMATED RADAR IMAGERY ALSO SHOWS 
IMPROVED FRAGMENTED BANDING WRAPPING FROM WEST OF OKINAWA OVER 
SOUTHERN OKINAWA INTO THE EASTERN QUADRANT OF THE LLC. SURFACE 
OBSERVATIONS SUPPORT THE INITIAL POSITION OVER OKINAWA, WITH 
RELATIVELY WEAK CORE WINDS. KITAHARA AND ASHIMINI ARE REPORTING THE 
MAXIMUM WINDS OF 22 KNOTS (10-MINUTE AVERAGE), OR APPROXIMATELY 23 
KNOTS CONVERTED TO 1-MINUTE AVERAGE. THE INITIAL POSITION IS ASSESSED 
WITH HIGH CONFIDENCE BASED ON RADAR IMAGERY, MSI IMAGERY AND SURFACE 
OBSERVATIONS. THE INITIAL INTENSITY OF 25 KNOTS IS ASSESSED WITH HIGH 
CONFIDENCE BASED ON SURFACE OBSERVATIONS. ENVIRONMENTAL CONDITIONS ARE 
MARGINALLY FAVORABLE, WITH MODERATE EQUATORWARD OUTFLOW AND WEAK 
POLEWARD OUTFLOW, INHIBITED BY A TUTT CELL POSITIONED TO THE NORTHWEST 
AND DRY AIR ENTRAINMENT OFFSET BY LOW VERTICAL WIND SHEAR AND WARM SST 
VALUES.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT, WITH
SUBTROPICAL RIDGE (STR) TO THE EAST AND NORTH AND NEAR-EQUATORIAL
RIDGE (NER) TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   KNES: T1.0 - 25 KTS
   CIMSS ADT: 34 KTS AT 270000Z
   CIMSS AIDT: 38 KTS AT 270000Z
   CIMSS D-MINT: 28 KTS AT 262207Z
   CIMSS D-PRINT: 25 KTS AT 270020Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL DEPRESSION (TD) 11W IS FORECAST TO
TRACK SLOWLY EAST-NORTHEASTWARD TO NORTHWARD THROUGH TAU 12 THEN TURN 
SHARPLY WEST-NORTHWESTWARD AS THE STR TO THE NORTH BECOMES THE 
DOMINANT STEERING INFLUENCE. THE SYSTEM WILL GRADUALLY INTENSIFY TO 30 
KNOTS BY TAU 12. AFTER TAU 12, TD 11W WILL ACCELERATE WEST-
NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF THE STR THROUGH 
LANDFALL, WHICH WILL OCCUR SOUTH OF SHANGHAI NEAR TAU 60. TD 11W
WILL SLOWLY INTENSIFY DUE TO DRY AIR ENTRAINMENT. HOWEVER, THE SYSTEM 
IS EXPECTED TO RE-MOISTEN JUST PRIOR TO LANDFALL, WITH A PEAK 
INTENSITY OF 45 KNOTS NEAR TAU 60. AFTER LANDFALL, THE SYSTEM WILL 
RECURVE POLEWARD OVERLAND TOWARD A BREAK IN THE STR TO THE NORTH, WITH
STEADY WEAKENING AND DISSIPATION EXPECTED.  

MODEL DISCUSSION: WITH THE EXCEPTION OF EGRR, DETERMINISTIC MODEL 
GUIDANCE IS IN FAIR AGREEMENT, WITH AN 80NM CROSS-TRACK SPREAD AT TAU 
48. THE DETERMINISTIC AND ENSEMBLE MODELS DIVERGE THROUGH THE 
REMAINDER OF THE JTWC FORECAST, WITH MEDIUM OVERALL CONFIDENCE IN THE 
JTWC TRACK FORECAST. RELIABLE INTENSITY GUIDANCE INDICATES A PEAK 
INTENSITY RANGING FROM 35 TO 50 KNOTS BETWEEN TAU 36 TO TAU 72.  

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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