WDPN31 PGTW 130300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W (BAVI) WARNING NR 
07//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TC) 03W (BAVI), LOCATED APPROXIMATELY 78 NM SOUTH 
OF UJELANG, HAS TRACKED WESTWARD AT 17 KNOTS OVER THE PAST SIX
HOURS. ANIMATED MULTISPECRAL SATELLITE IMAGERY CONTINUES TO DEPICT 
DEEPENED CENTRAL CONVECTION WITH THE BULK OF THE DEEP CONVECTION 
SLIGHTLY SHEARED WESTWARD OF A CONSOLIDATING LOW-LEVEL CIRCULATION 
CENTER (LLCC). AN OLDER 122232Z ASCAT PASS SHOWED A WELL-DEFINED 
CIRCULATION WITH 40 TO 45 KNOT WINDS OVER THE NORTHERN SEMI-CIRCLE 
AND 35 TO 40 KNOT WINDS OVER THE SOUTHERN SEMI-CIRCLE. THE CURRENT 
POSITION IS BASED ON THE MSI AND SATELLITE FIXES FROM ALL REPORTING 
AGENCIES WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 45 KNOTS IS 
BASED ON DVORAK CURRENT INTENSITY ESTIMATE OF T3.0 FROM PGTW, KNES 
AND PHFO. UPPER-LEVEL ANALYSIS INDICATES THAT THE SYSTEM IS LOCATED 
IN A MARGINALLY-FAVORABLE ENVIRONMENT WITH HIGH (30 KNOT) VERTICAL 
WIND SHEAR OFFSET BY GOOD DIFFLUENCE ALOFT AND THE STORM MOTION.  TS 
BAVI IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A SUB-TROPICAL 
RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TS BAVI WILL CONTINUE TO TRACK WEST-NORTHWESTWARD UNDER THE 
DOMINANT STEERING STR. MARGINAL CONDITIONS ARE EXPECTED TO PERSIST 
ALLOWING TS BAVI TO SLOWLY INTENSIFY OVER THE NEXT 48 HOURS. 
AVAILABLE MODEL GUIDANCE OVERALL IS IN GOOD AGREEMENT THROUGH TAU 36 
AND SHOWS A BIFURCATION AT TAU 48. NORTHERN GROUP INCLUDING GFS, GFS 
ENSEMBLES, ECMWF, EGRR, AND HWRF INDICATES TC 03W TRACKS SLIGHTLY 
SOUTH OF GUAM WHILE THE SOUTHERN GROUP INCLUDING NAVGEM AND JENS 
TAKE THE SYSTEM FURTHER SOUTH OF THE MARIANAS. JTWC TRACK FORECAST 
HAS BEEN CONSISTENT AND FAVORS THE NORTHERN GROUP POSITIONING THE 
FORECAST TRACK SLIGHTLY SOUTH OF GUAM.
   C. TS 03W IS FORECAST TO MAINTAIN A MORE WESTWARD TRAJECTORY. DUE 
TO UNCERTAINTY IN THE EXTENT OF THE STEERING STR AND FORECAST 
INTENSITY IN THE EXTENDED TAUS, THERE IS LOW CONFIDENCE IN THE JTWC 
FORECAST FOR THIS PORTION OF THE FORECAST PERIOD.//
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