WDPN31 PGTW 300300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 29W (KROSA)
WARNING NR 05//
RMKS//
 1. FOR METEOROLOGISTS
 2. 6-HOUR SUMMARY AND ANALYSIS:
    TROPICAL STORM (TS) 29W (KROSA), LOCATED APPROXIMATELY 507 NM EAST-
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 13 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS CONVECTIVE 
BANDING HAS DEEPENED AND WRAPPED TIGHTER INTO THE LOW-LEVEL CIRCULATION
CENTER (LLCC). A 292346Z SSMI/S IMAGE INDICATES THE FORMATION OF A
MICROWAVE EYE. THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION BASED ON THE
ABOVE ANIMATION AND ON THE MICROWAVE IMAGERY. THE INITIAL INTENSITY OF 40
KNOTS IS AVERAGED FROM DVORAK ESTIMATES OF 35 TO 45 KNOTS FROM ALL AGENCIES.
OVERALL, THE UPPER-LEVEL ENVIRONMENT IS FAVORABLE FOR FURTHER DEVELOPMENT 
WITH GOOD POLEWARD AND EQUATORWARD OUTFLOW WITH THE EXCEPTION OF THE EASTERN
QUADRANT, WHICH IS UNDER WEAK TO MODERATE (10-15 KNOT) EASTERLY VERTICAL WIND
SHEAR. TS 29W IS TRACKING WESTWARD UNDER THE STEERING INFLUENCE OF THE 
MID-LEVEL SUBTROPICAL RIDGE (STR) TO THE NORTH.
 3. FORECAST REASONING:
    A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
    B. TS 29W IS FORECAST TO TRACK GENERALLY WESTWARD UNDER THE STEERING 
INFLUENCE OF THE STR THROUGHOUT ITS LIFESPAN. FAVORABLE UPPER LEVEL CONDITIONS,
IN ADDITION TO PERENNIALLY WARM SEA SURFACE TEMPERATURES IN THE PHILIPPINE SEA
WILL ENSURE RAPID INTENSIFICATION THROUGH TAU 24 TO A PEAK INTENSITY OF 65 KNOTS
PRIOR TO MAKING LANDFALL INTO LUZON. AFTERWARDS, TS 29W WILL WEAKEN AS IT 
CROSSES THE MOUNTAIN RIDGES OF LUZON. ONCE THE SYSTEM EMERGES IN THE SOUTH CHINA
SEA, IT WILL ONCE AGAIN BEGIN TO RE-INTENSIFY.
    C. IN THE EXTENDED TAUS, TS KROSA WILL TRACK ACROSS HAINAN AND THE GULF OF 
TONKIN BEFORE MAKING LANDFALL NEAR HUE, VIETNAM BEFORE TAU 120. INTERACTION WITH
THE TOPOGRAPHY OF HAINAN AND VIETNAM WILL GRADUALLY ERODE THE SYSTEM. DYNAMIC 
MODEL GUIDANCE INDICATES TWO DISTINCT GROUPINGS WITH JGSM, JENS, NVGM AND EGRR 
INDICATING A WEAKER SYSTEM AND A MORE WEST-SOUTHWESTWARD TRACK WHILE ECMF AND 
GFS SHOW A STRONGER SYSTEM AND A MORE WESTWARD TRACK. THE JTWC FORECAST IS CLOSER
TO THE NORTHERN SOLUTIONS. GIVEN THE WELL-ESTABLISHED STEERING MECHANISM, THERE
IS HIGH CONFIDENCE IN THE NEAR- TO MID-TERM PORTION OF THE JTWC TRACK FORECAST.
HOWEVER, DUE TO THE UNCERTAINTY  IN THE INTENSITY AND THE SPREADING OF THE MODEL
GUIDANCE, THERE IS LOW CONFIDENCE IN THE EXTENDED PORTION OF THE FORECAST.  //
NNNN