WDPN31 PGTW 050300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 04W (NESAT)
/WARNING NR 24//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 050000Z TO 100000Z JUN 2005.
   A. TYPHOON (TY) 04W (NESAT), LOCATED APPROXIMATELY 545 NM SOUTH-
SOUTHEAST OF OKINAWA, HAS TRACKED NORTHWARD AT 07 KNOTS OVER THE PAST
SIX HOURS. 
   B. TY 04W IS FORECAST TO TRACK ALONG THE WESTERN PERIPHERY OF THE
MID-LEVEL STEERING RIDGE LOCATED NORTH AND EAST OF THE SYSTEM. THIS 
RIDGE IS EXPECTED TO WEAKEN SLIGHTLY IN THE MID-PERIOD ALLOWING TY 04W 
TO TRACK SLIGHTLY NORTHEASTWARD. A SHORT-TERM NORTHWARD TRACK IS FORECAST
BETWEEN TAUS 48 AND 72 CAUSED BY A PASSING MID-LATITUDE SHORTWAVE RIDGE 
BRIEFLY ENHANCING THE MID-LEVEL STEERING RIDGE. A LONG-WAVE TROUGH, 
CURRENTLY OVER CENTRAL CHINA IS EXPECTED TO WEAKEN THE STEERING RIDGE 
AFTER TAU 72 AND SHIFT TY 04W BACK TO A NORTHEASTWARD TRACK. MODELS ARE
IN GOOD AGREEMENT WITH SLIGHT DIFFERENCES TO SUB-TROPICAL RIDGE ORIEN-
TATION AND STRENGTH. THE SOLE OUTLIER AT THE EXTENDED TAUS IS UKMET EGRR
WHICH DOES NOT INDICATE A WESTWARD BUILDING OF THE SUB-TROPICAL RIDGE.
   C. WATER VAPOR AND MICROWAVE IMAGERY CONTINUE TO INDICATE EROSION
OF THE DEEP CONVECTION IN THE NORTHERN SEMI-CIRCLE DUE TO EASTERLY
SHEAR AND CONFLUENT FLOW ALOFT. POLEWARD OUTFLOW IS EXPECTED TO IMPROVE
IN THE MID-PERIOD CAUSED BY LINKAGE WITH THE LONG-WAVE TROUGH EAST OF
JAPAN AND THE POTENTIAL LINKAGE WITH A DEEPENING TUTT CELL TO THE EAST
OF TY 04W. THIS IMPROVED OUTFLOW SHOULD INCREASE INTENSITY BRIEFLY 
BEFORE TY 04W INTERACTS WITH THE TROUGH PROPAGATING OUT OF EASTERN
CHINA AND BEGINS A RAPID EXTRATROPICAL TRANSITION.
   D. CURRENT WIND RADII ARE BASED ON RECENT QUICKSCAT AND MICROWAVE 
IMAGERY. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE
SIZED SYSTEM.
   E. IN THE EXTENDED FORECAST, TY 04W IS EXPECTED TO INTERACT WITH
THE APPROACHING BAROCLINIC LOW, WEAKEN, ACCELERATE AND COMPLETE EXTRA-
TROPICAL TRANSITION BY TAU 120.
3. FORECAST TEAM: ALPHA//
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