WDPN33 PGTW 260300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 11W (CO-MAY)   
WARNING NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.3N 125.7E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 134 NM WEST-SOUTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 18 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A FULLY EXPOSED LOW-
LEVEL CIRCULATION (LLC), WITH FLARING, ISOLATED CONVECTION OVER THE 
EASTERN PERIPHERY, WHICH SUPPORTS THE INITIAL POSITION WITH HIGH 
CONFIDENCE. SURFACE OBSERVATIONS FROM MIYAKOJIMA INDICATE SUSTAINED 
WINDS OF LESS THAN 15 KNOTS, IN GENERAL, WITH MINIMUM SLP OF 994.4MB. 
HOWEVER, MAXIMUM WINDS ARE LIKELY DISPLACED OVER THE SOUTHEAST QUADRANT 
AS SHOWN IN RECENT ASCAT IMAGERY. THE INITIAL INTENSITY OF 25 KTS IS 
ASSESSED WITH MEDIUM CONFIDENCE BASED ON CIMSS OBJECTIVE ESTIMATES 
RANGING FROM 22-33 KNOTS.

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

CURRENT STEERING MECHANISM: LOW-LEVEL STEERING RIDGE POSITIONED TO
THE SOUTHEAST AND EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T3.0 - 45 KTS
   CIMSS ADT: 29 KTS AT 252030Z
   CIMSS AIDT: 33 KTS AT 252030Z
   CIMSS D-MINT: 24 KTS AT 252222Z
   CIMSS D-PRINT: 22 KTS AT 260020Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK EQUATORWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   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 EMBEDDED WITHIN AN 
EXTENSIVE SWATH OF SOUTHERLY FLOW THAT RUNS FROM THE EAST PHILIPPINE 
SEA NORTHWARD ALONG THE EASTWARD PERIPHERY OF THE SYSTEM, THEN 
NORTHWARD OVER THE RYUKYU ISLANDS. THIS ENHANCED FLOW PATTERN BETWEEN 
THE SYSTEM AND THE LOW-LEVEL STEERING RIDGE WILL PUSH TD 11W POLEWARD 
THROUGH THE FORECAST PERIOD. THE SYSTEM WILL STEADILY OPEN UP AND 
WEAKEN UNDER MARGINAL CONDITIONS TO INCLUDE DRY AIR AND LOW TO MODERATE 
VERTICAL WIND SHEAR. ADDITIONALLY, THE UPPER-LEVEL CIRCULATION IS 
DECOUPLED FROM THE LOW-LEVEL CIRCULATION, WHICH IS EMBEDDED WITHIN LOW- 
TO MID-LEVEL SOUTHERLY FLOW. AFTER TAU 12, THE SYSTEM IS EXPECTED TO 
DISSIPATE. HOWEVER, THE GLOBAL MODELS SHOW A BROAD TROUGH DEVELOPING 
ACROSS THE OKINAWA REGION, WITH A BELT OF 25-30 KNOT WINDS OVER THE 
NORTHERN PERIPHERY, AND POSSIBLE DEVELOPMENT OF A NEW, WEAK SURFACE LOW 
NEAR OKINAWA IN ONE TO TWO DAYS.           

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 12 THEN DIVERGE SIGNIFICANTLY (SO-CALLED SQUASHED SPIDER), 
WITH LOW CONFIDENCE IN THE JTWC FORECAST TRACK. ADDITIONALLY, THE CLOSE 
PROXIMITY OF TD 11W TO TD 11W (APPROXIMATELY 270NM SEPARATION DISTANCE) 
MAY RESULT IN BINARY INTERACTION, WHICH WILL FURTHER COMPLICATE THE 
FORECAST TRACK. RELIABLE INTENSITY GUIDANCE IS IN POOR AGREEMENT AFTER 
TAU 12 LIKELY DUE TO THE FORMATION OF ANOTHER LOW PRESSURE AREA NEAR 
OKINAWA. 

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