WDPN31 PGTW 020300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 29W (KROSA) WARNING NR 17//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 29W (KROSA), LOCATED APPROXIMATELY 188 NM
SOUTH-SOUTHEAST OF HONG KONG, HAS TRACKED WESTWARD AT 05 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
SHOWS THE SYSTEM HAS MAINTAINED INTENSELY DEEP CENTRAL CONVECTION AND
A 30-NM EYE. THERE IS HIGH CONFIDENCE IN THE INITIAL POSITION BASED
ON THE EYE FEATURE IN THE MSI ANIMATION. THE INITIAL INTENSITY OF 100
KNOTS IS AVERAGED FROM CLOSE DVORAK INTENSITY ESTIMATES FROM ALL
REPORTING AGENCIES. UPPER-LEVEL ANALYSIS INDICATES THE SYSTEM HAS
REACHED THE WESTERN EDGE OF THE STEERING SUBTROPICAL RIDGE (STR)
ANCHORED 10 DEGREES SOUTH OF JAPAN. THE CYCLONE IS IN AN AREA OF
LIGHT TO MODERATE (10-15 KNOT) VERTICAL WIND SHEAR (VWS). HOWEVER,
RADIAL OUTFLOW WITH A VERY STRONG POLEWARD COMPONENT - EVIDENT ON
ANIMATED WATER VAPOR IMAGERY - HAS FUELED THE DEEP CONVECTION. 
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. A NEW STR EXTENDING EASTWARD FROM THE INDOCHINA PENINSULA IS
EXPECTED TO ASSUME STEERING AND DEFLECT TYPHOON KROSA TO A
SOUTHWESTWARD TRAJECTORY OVER THE NEXT 12 HOURS. BY TAU 72, THE
SYSTEM WILL HAVE MADE LANDFALL INTO CENTRAL VIETNAM, JUST SOUTH OF
HUE. THE STRONG TYPHOON APPEARS TO HAVE PEAKED AND SHOULD BEGIN TO
GRADUALLY WEAKEN DUE TO INCREASING VWS AND THE INFLUX OF COOLER
CONTINENTAL DRY AIR FROM CHINA; PRIOR TO LANDFALL, IT WOULD HAVE
BEEN REDUCED TO TROPICAL DEPRESSION INTENSITY.  
   C. AFTER TAU 72, TY 29W WILL RAPIDLY DECAY AND DISSIPATE BY TAU 96
DUE TO FRICTIONAL EFFECTS IN ADDITION TO THE AFOREMENTIONED DYNAMICS.
NUMERIC MODEL GUIDANCE REMAINS IN GENERALLY TIGHT AGREEMENT WITH THE
JTWC FORECAST TRACK, WHICH IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS
WITH HIGH CONFIDENCE.  //
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