WDPN32 PGTW 130300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 07W (SEVEN) WARNING 
NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 30.9N 124.7E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 287 NM WEST-SOUTHWEST OF SASEBO, JAPAN
   MOVEMENT PAST 6 HOURS: EASTWARD AT 09 KTS
   SIGNIFICANT WAVE HEIGHT: 13 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A BROAD AND
ELONGATED LOW-LEVEL CIRCULATION WITH DEEP CONVECTION FLARING
POLEWARD AND EQUATORWARD OF THE LOW-LEVEL CIRCULATION (LLCC). WATER
VAPOR IMAGERY REVEALS AND UPPER-LEVEL CYCLONE DISPLACED SLIGHTLY TO
THE NORTHWEST OF THE LLCC. AN UPPER-LEVEL TROUGH APPROACHING FROM
THE NORTHWEST IS ALSO APPARENT ON WATER VAPOR IMAGERY. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED
ANIMATED MSI AND A 132218Z WSFM IMAGE REVEALING THE LOW-LEVEL BANDING. 
THE INITIAL INTENSITY IS PLACED WITH HIGH 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: A NEAR EQUATORIAL RIDGE TO THE SOUTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T1.0 - 25 KTS
   CIMSS ADT: 30 KTS AT 0200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 10-15 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: MODERATE RADIAL

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: SUBTROPICAL DEPRESSION (SD) 07W WILL CURVE
NORTHEASTWARD FOR THE FIRST 24 HOURS OF THE FORECAST AS THE SYSTEM 
IS INFLUENCED BY THE NEAR EQUATORIAL RIDGE TO THE SOUTH. FOLLOWING
TAU 24, A DEEP UPPER-LEVEL TROUGH WILL ENGULF THE LOW, INFLUENCING
THE SYSTEM TO CURVE NORTHWESTWARD THROUGH THE END OF THE FORECAST
PERIOD. THE SYSTEM IS ANTICIPATED TO REMAIN SUBTROPICAL IN NATURE
FOR THE ENTIRETY OF THE FORECAST, WITH A LOW PROBABILITY OF
DEVELOPING A TROPICAL CYCLONE. AS THE TROUGH DEEPENS AFTER TAU 24,
THE SYSTEM IS ANTICIPATED TO SLIGHTLY INTENSIFY TO 40KTS AT TAU 36
DUE TO BAROCLINIC FORCING. A PERIOD OF WEAKENING WILL FOLLOW DUE TO
TOPOGRAPHIC INTERACTION AS SD 07W INTERACTS WITH THE TOPOGRAPHY OF
THE KOREAN PENINSULA.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GENERAL
AGREEMENT THAT SD 07W CURVE NORTHWARD FOR THE REMAINDER OF THE
FORECAST PERIOD. HOWEVER, THE GEFS ENSEMBLE INDICATES A BIFURCATION
SCENARIO WHERE SD 07W TRACKS DUE EAST-NORTHEAST FOR THE REMAINDER
OF THE FORECAST. ECENS ALSO REVEALS A BROAD SWATH OF TRACK
SOLUTIONS, BUT HAS A MUCH WEAKER SIGNAL OVERALL. THE INTENSITY
GUIDANCE IS IN GOOD AGREEMENT THAT SD 07W WILL PEAK BETWEEN
35-40KTS FOLLOWED BY A PERIOD OF CONTINUOUS WEAKENING.

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