WDPN33 PGTW 270900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 11W (CO-MAY) WARNING 
NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 26.6N 129.5E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 91 NM EAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: EASTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
DISORGANIZED AREA OF TROUGHING MERGING INTO THE LOW-LEVEL
CIRCULATION CENTER (LLCC) OF TROPICAL DEPRESSION (TD) 11W, CREATING
AN ELONGATED CIRCULATION ON A NORTHWEST TO SOUTHEAST AXIS. CLEAR,
DRY AIR IS EVIDENT TO THE NORTHWEST ON WATER VAPOR IMAGERY DUE TO
AN UPPER-LEVEL CYCLONE. IN ADDITION TO THE UNFAVORABLE THE DRY AIR
IMPOSED FROM THE NORTHWEST, THE CYCLONE INHIBITS POLEWARD OUTFLOW
UNFAVORABLY. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE
BASED ON THE AFOREMENTIONED ANIMATED MSI AND DUE TO THE BROAD
NATURE OF THE CONSOLIDATING SYSTEM. THE INITIAL INTENSITY OF 30 KTS
IS ASSESSED WITH LOW CONFIDENCE BASED ON THE AGENCY AND OBJECTIVE
FIXES LISTED BELOW.

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

CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT BETWEEN
A SUBTROPICAL RIDGE TO THE NORTH AND A NEAR EQUATORIAL RIDGE TO THE
SOUTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RCTP: T1.5 - 25 KTS
   KNES: T1.5 - 25 KTS
   CIMSS SATCON: 47 KTS AT 270439Z
   CIMSS ADT: 45 KTS AT 270530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: LOW
   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: TS 11W WILL CURVE NORTHWARD ERRATICALLY WHILE
REMAINING IN A WEAK AND COMPETING STEERING ENVIRONMENT BETWEEN THE
DEEP LAYER RIDGE TO THE NORTH AND THE SOUTH. AFTER TAU 12, THE NEAR
EQUATORIAL RIDGE TO THE SOUTH WILL WEAKEN, ALLOWING THE SUBTROPICAL
RIDGE TO THE NORTH TO DRIVE TS 11W ON A NORTHWESTWARD CURVE.
DURING THE FIRST 36 HOURS OF THE FORECAST, THE SYSTEM WILL REMAIN
IN A MARGINALLY FAVORABLE ENVIRONMENT WITH LOW VERTICAL WIND SHEAR
AND A MODERATELY DIVERGENT UPPER-LEVEL ENVIRONMENT. DRY AIR
ASSOCIATED THE UPPER-LEVEL CYCLONE TO THE NORTHWEST WILL INHIBIT
INTENSIFICATION THROUGH TAU 36. BY TAU 48, TD 11W WILL MOISTEN AND
REACH A PEAK INTENSITY OF 40KTS. LANDFALL WILL OCCUR SHORTLY
FOLLOWING TAU 72, LEADING TO DISSIPATION OVER LAND BY TAU 120 DUE
TO TOPOGRAPHIC INTERACTION.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
THAT TD 11W WILL CURVE NORTHWESTWARD ON THE SOUTHERN PERIPHERY OF
THE RIDGE TO THE NORTH. THE ENSEMBLE GUIDANCE REVEALS A SLIGHTLY
LARGER SPREAD AND BIFURCATION AFTER LANDFALL. FEW MEMBERS OF BOTH
GEFS AND ECENS REMAIN OVER WATER, RECURVING SHORT OF THE COASTLINE.
THE INTENSITY GUIDANCE REVEALS VARYING MODEL SOLUTIONS BASED ON
WHETHER OR NOT THE VORTEX TRACKERS REMAIN OVER WATER. COAMPS-TC AND
HWRF CONTINUOUSLY INTENSIFY THE SYSTEM THROUGHOUT THE FORECAST
PERIOD WHILE GFS AND HAFS-A WEAKEN THE SYSTEM AFTER TAU 48.

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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