WDPN32 PGTW 050300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 10W (LINFA) WARNING NR 
13//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 10W (LINFA), LOCATED APPROXIMATELY 195 NM 
NORTH-NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-
NORTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. RECENT MSI 
DEPICTS THE SYSTEM HAS MOVED OVERLAND AND THE DEEP CONVECTION IS 
OBSCURING THE LLCC.  FOR THIS REASON, THE CURRENT POSITION IS BASED 
ON THE MSI AND PGTW SATELLITE FIX WITH FAIR CONFIDENCE. THE CURRENT 
INTENSITY OF 45 KNOTS IS BASED ON THE SLIGHTLY WEAKENED STRUCTURE AS 
THE SYSTEM TRACKS OVERLAND. UPPER-LEVEL ANALYSIS INDICATES THE 
SYSTEM REMAINS IN AN AREA OF MODERATE (20 KNOT) NORTHEASTERLY VWS 
BEING OFFSET BY EXCELLENT EQUATORWARD OUTFLOW. TS 10W IS CURRENTLY 
TRACKING UNDER THE STEERING INFLUENCE OF THE STR TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM 
THE PREVIOUS PROGNOSTIC REASONING MESSAGE. HOWEVER, THE JTWC TRACK 
HAS SHIFTED AS THE SYSTEM MOVED OVERLAND.
   B. TS 10W WILL TRACK GENERALLY WESTWARD IN THE SHORT TERM UNDER 
THE STEERING INFLUENCE OF THE STR. THE SYSTEM IS EXPECTED TO 
SLIGHTLY WEAKEN AS IT CROSSES NORTHERN LUZON. BY TAU 24, 
MODERATE VWS WILL PERSIST, BUT FAVORABLE SST AND OHC WILL ALLOW TS 
10W TO SLIGHTLY INTENSIFY AS IT MOVES OVER LUZON STRAIT. 
CONCURRENTLY, THE SYSTEM IS FORECAST TO TURN POLEWARD TOWARDS A 
BREAK IN THE STEERING STR.
   C. AFTER TAU 72, SLOW MOVEMENT AND WEAKENING TREND ARE EXPECTED 
AS THE SYSTEM CONTINUES TO TRACK NORTHWARD. DYNAMIC MODEL GUIDANCE 
HAS SLIGHTLY IMPROVED, BUT STILL SHOWS SIGNIFICANT DIFFERENCES IN 
THE TRACK SPEEDS. THIS IS DUE TO THE COMPLEX STEERING ENVIRONMENT 
WITH THE BREAK IN THE STR, POSSIBLE DIRECT CYCLONE INTERACTION WITH 
TS 09W, AND STRONG WESTERLY FLOW AT THE LOW AND MID LEVELS SOUTH OF 
THE SYSTEM. DUE TO THE COMPLEX ENVIRONMENT AND UNCERTAINTY IN THE 
FORECAST INTENSITY IN THE EXTENDED TAUS, THE OVERALL JTWC FORECAST 
CONFIDENCE LEVEL IS LOW.//
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