WDPN31 PGTW 090300Z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W WARNING NR 05//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TROPICAL STORM (TS) 05W (DIANMU), LOCATED APPROXIMATELY 120 NM 
WEST-SOUTHWEST OF OKINAWA, JAPAN, HAS TRACKED NORTHWARD AT 10 KNOTS 
OVER THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY AND A 082216Z SSMIS 37H GHZ MICROWAVE IMAGE DEPICT A 
PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER WITH A MAJORITY OF 
THE DEEP CONVECTIVE BANDING TO THE SOUTH AND EAST OF THE SYSTEM. 
OBSERVATIONS FROM MIYAKOJIMA ISLAND (MINIMUM PRESSURE OF 992 MB WITH 
WESTERLY WINDS BETWEEN 15 AND 25 KNOTS SUSTAINED) AND A RADAR LOOP 
FROM JAPAN REVEAL THAT THE SYSTEM PASSED SLIGHTY EAST OF THE ISLAND
BETWEEN 081800Z AND 082200Z. THESE OBSERVATIONS AS WELL AS MICROWAVE 
AND VISIBLE SATELLITE IMAGERY CONFIRM THE ASYMETRIC WIND  
DISTRIBUTION OF TS 05W. THE CURRENT INTENSITY IS BASED ON DVORAK 
ESTIMATES FROM PGTW, KNES, AND RJTD OF 30 TO 35 KNOTS. HOWEVER, 
STRONGER GRADIENT WINDS ARE EVIDENT ALONG THE SOUTHEASTERN QUADRANT. 
UPPER LEVEL ANALYSIS INDICATES SUBSIDENCE TO THE NORTH OF TS 05W 
ASSOCIATED WITH AN UPPER LEVEL TROUGH, BUT GOOD EQUATORWARD OUTFLOW 
ASSOCIATED WITH A DIFFLUENT REGION SOUTHWEST OF THE SYSTEM.
 3. FORECAST REASONING.
   A. THE FORECAST REASONING IS SIMILAR TO THE PREVIOUS TRACK 
PHILOSOPHY. HOWEVER, IN THIS FORECAST THE SYSTEM IS NOT EXPECTED TO 
INTENSIFY TO 45 KNOTS BASED ON INTENSITY GUIDANCE AND THE FACT THAT 
THE UPPER LEVEL TROUGH NORTH OF THE SYSTEM IS INHIBITING OUTFLOW AND 
THE DEVELOPMENT OF DEEP CONVECTION ALONG THE NORTHERN PERIPHERY OF 
THE SYSTEM. 
   B. TS 05W IS CURRENTLY TRACKING ALONG THE WESTERN PERIPHERY OF A 
SOUTHERN EXTENSION OF THE SUBTROPICAL STEERING RIDGE ANCHORED TO THE 
EAST OF JAPAN AND WILL CONTINUE TRACKING NORTHWARD THROUGH TAU 48. 
SLIGHT INTENSIFICATION IS EXPECTED AS THE SYSTEM TRACKS OVER WARM 
SEA SURFACE TEMPERATURES AND THROUGH AN AREA OF LOW VERTICAL
WIND SHEAR. 
   C. BETWEEN TAU 48 AND TAU 72 TS 05W IS FORECAST TO BEGIN TO 
RECURVE AND MAKE LANDFALL OVER SOUTH KOREA. INTERACTION WITH LAND 
AND AN APPROACHING BAROCLINIC ZONE TO THE NORTH IS EXPECTED TO 
WEAKEN THE SYSTEM. BETWEEN TAU 72 AND TAU 96 TS DIANMU IS FORECAST TO
COMPLETE EXTRATROPICAL TRANSITION AS IT BECOMES ABSORBED INTO THE 
MID-LATITUDE WESTERLY FLOW. NUMERICAL MODEL GUIDANCE IS IN GOOD 
AGREEMENT. ECMWF HAS SHIFTED WESTWARD AND IS NOW ALIGNED WITH THE 
TIGHTLY PACKED AIDS ENVELOPE. GFDN REMAINS AN OUTLIER AS IT 
ERRONEOUSLY DRIVES THE SYSTEM WESTWARD. THIS FORECAST IS IN GOOD 
AGREEMENT WITH THE MODEL CONSENSUS.//
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