WDPN31 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W (YAGI) WARNING NR 
09//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 03W (YAGI), LOCATED APPROXIMATELY 344 NM WEST OF 
IWO JIMA, JAPAN, HAS TRACKED NORTHEASTWARD AT 12 KNOTS OVER THE PAST 
SIX HOURS. ANIMATED INFRARED IMAGERY (IR) REVEALS A TIGHTLY WRAPPED 
LOW LEVEL CIRCULATION CENTER THAT IS SURROUNDED BY SHALLOW 
CONVECTION WHILE DEEP CONVECTION HAS REMAINED LIMITED. THE INITIAL 
POSITION IS BASED ON IR LOOP AND SEVERAL POSITION FIXES WITH FAIR 
CONFIDENCE. THE INITIAL INTENSITY HAS BEEN INCREASED TO 45 KNOTS 
BASED ON DVORAK CURRENT INTENSITY ESTIMATES FROM PGTW AND RJTD. 
UPPER LEVEL ANALYSIS INDICATES TS 03W IS NORTH OF AN ANTICYCLONE IN 
AN AREA OF MODERATE (15-20 KNOT) VERTICAL WIND SHEAR (VWS). ANIMATED 
WATER VAPOR IMAGERY FURTHER REVEALS SUBSIDENCE ALONG THE WESTERN 
PORTION OF THE STORM CONTINUES TO IMPINGE ON THE OUTFLOW TO THE 
WEST, WHILE POLEWARD OUTFLOW HAS INCREASED SLIGHTLY INTO THE 
MIDLATITUDE WESTERLIES. TS 03W IS CURRENTLY TRACKING ALONG THE 
NORTHWESTERN EDGE OF THE SUBTROPICAL RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM 
THE PREVIOUS PROGNOSTIC REASONING.
   B. TS 03W WILL CONTINUE TO TRACK POLEWARD UNDER THE STEERING 
INFLUENCE OF THE STR THROUGH TAU 24. AFTER TAU 24, THE SYSTEM IS 
EXPECTED TO SLOW AND TRACK EASTWARD AS A LOWER LEVEL STEERING RIDGE 
BUILDS SOUTH OF THE SYSTEM. TS 03W IS EXPECTED TO HOLD ITS INTENSITY 
FOR THE NEXT 12 HOURS AS OUTFLOW AND SEA SURFACE TEMPERATURES REMAIN 
FAVORABLE. AFTER TAU 12, COOL (<26 DEGREES CELSIUS) SSTS AND 
INCREASING VWS WILL WEAKEN THE SYSTEM AND CAUSE DISSIPATION BY TAU 
72. DYNAMIC MODEL GUIDANCE IS SPREAD WITH SOME SLIGHT DISAGREEMENT 
ON THE ORIENTATION OF THE STEERING RIDGE IN THE EXTENDED TAUS. DUE 
TO THIS DISAGREEMENT, THE OFFICIAL FORECAST TRACK IS LAID CLOSE TO 
MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.//
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