WDPN34 PGTW 130900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 09W (NINE) WARNING 
NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 27.6N 150.3E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 712 NM SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A SMALL-SIZED
SYSTEM WITH FRAGMENTED, SHORT, FORMATIVE BANDS AND A SHALLOW CENTRAL
DENSE OVERCAST TRAILING A PARTIALLY EXPOSED LOW LEVEL CIRCULATION
(LLC). THIS SYSTEM IS THE THIRD IN A SERIES OF TROPICAL CYCLONES
TRACKING POLEWARD ALONG THE EASTERN RIM OF A MONSOON GYRE. THE
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A DEFINED
MICROWAVE LLC FEATURE IN THE 130519Z SSMIS IMAGE SUITE. THE INITIAL
INTENSITY OF 25KTS IS ALSO ASSESSED WITH HIGH CONFIDENCE BASED ON A
RECENT ASCAT PASS AND ON THE AVERAGE OF AGENCY AND AUTOMATED DVORAK
ESTIMATES THAT IS CONSISTENT WITH THE VIRTUALLY UNCHANGED
CONVECTIVE STRUCTURE OF THE SYSTEM OVER THE PAST SIX HOURS. ANALYSIS
INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH WARM SST AND
MODERATE VENTILATION OFFSET BY MODERATE VWS AND CONVECTIVE
SUBSIDENCE ASSOCIATED WITH AN UPPER LEVEL LOW TO THE NORTH.

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

CURRENT STEERING MECHANISM: LOW- TO MID-LEVEL SUBTROPICAL RIDGE
(STR) TO THE EAST THROUGH SOUTHEAST.


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.0 - 25 KTS
   RJTD: T1.5 - 25 KTS
   CIMSS ADT: 30 KTS AT 130630Z
   CIMSS DPRINT: 29KTS AT 130630Z 
   CIMSS DMINT: 25KTS AT 1300521Z 

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

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: TD 09W WILL TRACK MORE NORTHWARD THEN
NORTH-NORTHWESTWARD AS THE EASTERN EXTENSION OF THE STR ASSUMES
STEERING. AFTER TAU 48, THE SYSTEM WILL BEGIN TO ACCELERATE
NORTHEASTWARD AS IT ROUNDS THE STR AXIS OF A RECEDING STR THAT IS
WEAKENED BY THE UPPER LEVEL LOW. THE MARGINALLY FAVORABLE
ENVIRONMENT WILL FUEL A MODEST INTENSIFICATION TO A PEAK OF 35KTS
BY TAU 24. AFTERWARD, DRY AIR ENTRAINMNENT FROM THE NORTHWEST AND
INCREASING VWS WILL GRADUALLY ERODE THE SYSTEM TO DISSIPATION BY
TAU 72.  

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH AFUM
AS THE SOLE AND EXTREME LEFT-OF-TRACK OUTLIER, LENDING HIGH
CONFIDENCE TO THE JTWC FORECAST TRACK THAT IS LAID JUST TO THE
RIGHT OF CONSENSUS TO OFFSET AFUM. THERE IS MEDIUM CONFIDENCE IN
THE INTENSITY FORECAST.  

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