WDPN31 PGTW 110300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W
/WARNING NR 20//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TROPICAL STORM (TS) 03W, AERE, LOCATED APPROXIMATELY 130 NM 
SOUTHWEST OF KADENA AB, OKINAWA, HAS TRACKED NORTHEASTWARD AT 17 
KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL 
SATELLITE IMAGERY (MSI) SHOWS AN EXPOSED LOW LEVEL CIRCULATION 
CENTER (LLCC) WITH CONVECTION SHEARED TO THE EAST. AN 11/2154Z SSMIS 
MW IMAGE ALSO INDICATES A WELL-DEFINED LLCC WITH CONVECTION ALONG 
THE EASTERN PERIPHERY OF THE CIRCULATION AND DRY AIR ENCOMPASSING 
THE WESTERN SEMICIRCLE. WATER VAPOR IMAGERY INDICATES UPPER LEVEL 
DIFFLUENCE TO THE EAST OF THE SYSTEM WHILE POLEWARD OUTFLOW IS 
BECOMING MORE SUBDUED. CURRENT INTENSITY IS BASED ON A PGTW DVORAK 
INTENSITY ESTIMATE OF 30 KNOTS AND PRESSURE OBSERVATIONS FROM NEARBY 
SHIP REPORTS AND BUOYS INDICATING WINDS NEAR 35 KNOTS. POSITION 
CONFIDENCE IS FAIR BASED ON A LARGE, EXPOSED LLCC AND RJTD RADAR 
FIXES. UPPER LEVEL ANALYSIS SHOWS TS 03W IS TRACKING ALONG THE 
NORTHWEST PERIPHERY OF A MID-LEVEL STEERING RIDGE IN A REGION OF 
INCREASING VERTICAL WIND SHEAR (VWS). ANALYSIS ALSO INDICATES TS 03W 
IS BENEATH A SUBTROPICAL TROUGH, WHICH IS CAUSING SUBSIDENCE AND 
RESULTING IN A LACK OF CONVECTION ON THE WESTERN SIDE OF THE STORM. 
THIS SYSTEM IS CURRENTLY TRACKING THROUGH INCREASINGLY UNFAVORABLE 
(23-25 DEGREES CELSIUS) SEA SURFACE TEMPERATURES (SST).       
3. FORECAST REASONING.
   A. NO SIGNIFICANT CHANGE TO FORECAST PHILOSOPHY.
   B. TS 03W IS EXPECTED TO MAINTAIN INTENSITY DURING THE NEXT 12 
HOURS AS IT CONTINUES TO TRACK NORTHEASTWARD AROUND THE SUBTROPICAL 
STEERING RIDGE. WITHIN 12-24 HOURS TS AERE IS EXPECTED TO DECREASE 
IN INTENSITY AS IT TRACKS OVER UNFAVORABLE SEA SURFACE TEMPERATURES, 
INTERACTS WITH THE BAROCLINIC ZONE, AND ENCOUNTERS INCREASED 
VERTICAL WIND SHEAR AS IT BECOMES EXTRATROPICAL. WITH THE EXCEPTION 
OF WBAR AND EGRR, MODEL GUIDANCE IS IN EXCELLENT AGREEMENT THROUGH 
TAU 48. WBAR STRUGGLES WITH THE STEERING RIDGE AND TRENDS MORE 
SOUTHERLY WHILE THE EGRR TRACKER TRENDS NORTHWARD ACROSS HONSHU, 
INDICATING DIFFICULTY IN HANDLING EXTRATROPICAL TRANSITION. DUE TO 
EGRR PULLING CONSENSUS TO THE NORTH, THIS FORECAST IS JUST SOUTH OF 
CONSENSUS AND REMAINS CONSISTENT WITH THE PREVIOUS FORECAST.//
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