WDPN31 PGTW 071500  
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W WARNING
/NR 12//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 071200Z0 TO 121200Z6 JUN 2004.
   A. TROPICAL STORM (TS) 07W, LOCATED APPROXIMATELY 195 NM NORTH-
NORTHWEST OF MANILA, PHILIPPINES, HAS TRACKED NORTH-NORTHEASTWARD
AT 06 KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED
ON 071130Z2 ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING
INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 45
AND 55 KNOTS. 
   B. TS 07W IS FORECAST TO TRACK ALONG THE WESTERN PERIPHERY OF
THE BUILDING SUBTROPICAL RIDGE LOCATED EAST OF THE SYSTEM. A MAJOR
SHORTWAVE IN CENTRAL ASIA IS EXPECTED TO APPROACH FROM THE WEST
AND LINK UP WITH TS 07W IN THE VICINITY OF TAIWAN AND ACCELERATE
TS 07W POLEWARD. TS 07W WILL BEGIN TRANSITIONING INTO AN
EXTRATROPICAL LOW LATE IN THE FORECAST PERIOD. THE AVAILABLE
DYNAMIC AIDS CONSISTING OF NGPS, GFDN, UKMO, GFDN, AVN, AFWA MM5,
COAMPS, WBAR, TCLAPS, JGSM AND JTYM HAVE EVOLVED INTO TWO DISTINCT
SOLUTION CLUSTERS. THE FIRST CLUSTER OF JTYM, GFDN, AND COAMPS
FORECASTS A SLOW, WEST-NORTHWESTWARD TRACK TOWARDS MAINLAND CHINA
DUE TO LITTLE OR NO INTERACTION WITH THE SHORTWAVE APPROACHING
FROM CENTRAL ASIA. THE SECOND CLUSTER OF A RENTERED NOGAPS TRACK,
AFWA MM5, TCLAPS, NCEP GFS AND UKMO FORECAST TS 07W TO LINK UP
WITH THE SHORTWAVE AND ACCELERATE POLEWARD AS AN EXTRATROPICAL
LOW. THIS FORECAST IS BASED ON A BLEND OF THE SECOND CLUSTER OF
NUMERICAL MODEL AIDS.
   C. TS 07W IS FORECAST TO INTENSIFY AT A LESS THAN A
CLIMATOLOGICAL RATE UNDER THE INFLUENCE OF EQUATORWARD OUTFLOW. TS
07W WILL REACH PEAK INTENSITY AS IT APPROACHES THE SOUTHERN COAST
OF TAIWAN DUE TO THE APPROACH OF THE SHORTWAVE FROM THE WEST,
WHICH WILL BRIEFLY ENHANCE THE POLEWARD OUTFLOW. TS 07W WILL THEN
WEAKEN DUE TO LAND INTERACTION WITH TAIWAN AND WEAKEN FURTHER LATE
IN THE FORECAST PERIOD AS TS 07W EXPERIENCES COOLER SEA SURFACE
TEMPERATURES AND INCREASED VERTICAL SHEAR FROM THE MID-LATITUDE
WESTERLIES.
   D. CURRENT WIND RADII AND FORECAST WIND RADII ARE BASED ON
CLIMATOLOGY FOR AN AVERAGE SIZED SYSTEM. 
   E. THE EXTENDED FORECAST HAS TS 07W ACCELERATING POLEWARD AS IT
BECOMES COMPLETELY EMBEDDED IN THE MID-LATITUDE WESTERLIES AND
COMPLETES FULL TRANSITION TO AN EXTRATROPICAL LOW.
3. FORECAST TEAM: GRUBER/FJELD/VOHS//

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