WDPN32 PGTW 041500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (FIVE) WARNING NR 
07//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 05W (HAISHEN), LOCATED APPROXIMATELY 109 NM 
NORTH OF CHUUK, HAS TRACKED NORTHWESTWARD AT 06 KNOTS OVER THE PAST 
SIX HOURS. ANIMATED ENHANCED IR (EIR) IMAGERY SHOWS CONTINUED 
CONVECTIVE BANDS WRAPPING INTO THE LOW LEVEL CIRCULATION CENTER. THE 
INITIAL POSITION IS BASED ON THE EIR LOOP AND A 041109Z METOP-A 
IMAGE. THE INITIAL INTENSITY OF 45 KNOTS IS BASED ON DVORAK 
INTENSITY ESTIMATES FROM ALL AGENCIES. UPPER-LEVEL ANALYSIS 
INDICATES A MARGINALLY-FAVORABLE ENVIRONMENT WITH MODERATE (10 TO 20 
KNOT) VERTICAL WIND SHEAR (VWS) AND SOME RADIAL OUTFLOW. TS 05W IS 
CURRENTLY TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF A 
RETREATING EXTENSION OF THE SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 05W WILL TRANSITION TO THE STEERING INFLUENCE OF A NEAR 
EQUATORIAL RIDGE (NER) TO THE SOUTHEAST BY TAU 12. AT THIS TIME THE 
SYSTEM TO TRACK TO THE NORTH-NORTHWEST. TS 05W  MAY BE ALLOWED TO 
INTENSIFY TO A PEAK OF 50 KNOTS OVER THE NEXT 12 HOURS AS IT TRACKS 
TO THE WEST. HOWEVER, BEYOND THAT, EXPECT A STEADY DECREASE IN 
INTENSITY DUE TO AN INCREASE IN VWS WITH THE SYSTEM COMPLETELY 
DISSIPATING BY TAU 72. THE SIGNIFICANT VARIATIONS IN DYNAMIC MODEL 
GUIDANCE IS DUE TO THE COMPLEX STEERING ENVIRONMENT AND THE WEAKNESS 
OF THE SYSTEM, LEADS TO LOW CONFIDENCE IN THE JTWC FORECAST TRACK.//
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