15:00 UTC warning at 50kts.Landfall in mainland China at 115kts.
WDPN31 PGTW 051500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (CHAN-HOM) WARNING
NR 21//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 09W (CHAN-HOM), LOCATED APPROXIMATELY 85 NM
NORTH-NORTHWEST OF ANDERSEN AFB, HAS TRACKED NORTHWESTWARD AT 13
KNOTS OVER THE PAST SIX HOURS. NOTE THE ACTUAL TRACK MOTION WAS MORE
ERRATIC: AFTER COMPLETING ITS LOOP NEAR ROTA, TS 09W SPED NNW FOR
ABOUT 3 HOURS THEN TURNED SHARPLY WESTWARD TO ITS CURRENT POSITION.
ANIMATED INFRARED SATELLITE IMAGERY DEPICTS IMPROVED CONVECTIVE
BANDING WRAPPING BROADLY INTO THE LOW-LEVEL CIRCULATION CENTER
(LLCC). A 051001Z SSMIS 91 GHZ IMAGE SHOWS A DEFINED MICROWAVE EYE
FEATURE WITH DEEP CONVECTIVE BANDING PRIMARILY CONFINED TO THE
WESTERN SEMI-CIRCLE. THIS IMAGE, ALONG WITH A 051159Z ASCAT IMAGE,
LENDS GOOD CONFIDENCE TO THE CURRENT POSITION. THE CURRENT INTENSITY
IS ASSESSED AT 50 KNOTS BASED ON AN AVERAGE OF DVORAK ESTIMATES
RANGING FROM 45 TO 55 KNOTS. UPPER-LEVEL ANALYSIS INDICATES
TS 09W IS LOCATED IN AN AREA OF LOW VWS WITH GOOD EQUATORWARD AND
POLEWARD OUTFLOW, ENHANCED BY THE TUTT CELL TO THE NORTHEAST. TS 09W
IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE DEEP-LAYERED STR.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TS 09W IS FORECAST TO RESUME A WEST-NORTHWESTWARD TO
NORTHWESTWARD TRAJECTORY UNDER THE STEERING INFLUENCE OF THE STR
ENTRENCHED TO THE NORTH. WITH THE EXCEPTION OF NAVGEM, THE DYNAMIC
GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 72. NAVGEM IS DISCOUNTED
AS IT CONTINUES TO DRIVE THE SYSTEM DIRECTLY INTO THE STRONG STR
WHILE THE REMAINDER OF THE MODELS PROVIDE A MORE REALISTIC TRACK
SOUTH OF OKINAWA. TS 09W IS FORECAST TO INTENSIFY STEADILY THROUGH
TAU 72 TO AN INTENSITY OF 120 KNOTS DUE TO FAVORABLE CONDITIONS.
C. AFTER TAU 72, TS 09W WILL CONTINUE TO TRACK NORTHWESTWARD
UNDER THE INFLUENCE OF THE DOMINANT STEERING STR. VWS AND UPPER
LEVEL DIVERGENCE WILL REMAIN FAVORABLE THROUGH THE END OF THE
FORECAST PERIOD; HOWEVER, COOLER SST AND LOWER OHC VALUES WILL BEGIN
TO WEAKEN THE SYSTEM. THE SYSTEM IS EXPECTED TO PEAK AT 125 KNOTS BY
TAU 96. DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT (WITH THE
EXCEPTION OF NAVGEM, WHICH REMAINS THE SOLE OUTLIER AS NOTED
EARLIER). DUE TO THE TIGHT GROUPING AMONG AVAILABLE TRACKERS, THE
JTWC TRACK FORECAST CONFIDENCE LEVEL REMAINS HIGH.//
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