Tropical Storm HAIKUI Advisory Tu, 07-08

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W (HAIKUI) WARNING
NR 15//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 12W (HAIKUI), LOCATED APPROXIMATELY 150 NM WEST-
NORTHWEST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED WESTWARD AT
06 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY AND A 060603Z AMSU-B MICROWAVE IMAGE SHOW THAT THE DEEPEST
CONVECTIVE BAND REMAINS WITHIN THE SOUTHEASTERN QUADRANT. THE
CURRENT POSITION IS BASED ON THE ABOVE MENTIONED IMAGERY WITH HIGH
CONFIDENCE. DVORAK ESTIMATES RANGE FROM 55-65 KNOTS FROM RJTD/KNES
AND PGTW RESPECTIVELY. THE CURRENT INTENSITY WAS HEDGED TO 60 KNOTS
BASED ON THE 060600Z SATCON ESTIMATE OF 68 KNOTS. UPPER-LEVEL
ANALYSIS INDICATES TS 12W HAS A POINT SOURCE OF DIVERGENCE DIRECTLY
OVERHEAD WHICH IS PROVIDING FOR EXCELLENT EXHAUST AND WEAK VERTICAL
WIND SHEAR. ANIMATED WATER VAPOR IMAGERY AND THE 060000Z 500 MB
ANALYSIS INDICATE THAT TS 12W IS BEING STEERED WESTWARD BY THE
SUBTROPICAL RIDGE (STR) TO THE NORTH. THE MID-LATITUDE TROUGH THAT
HAD PREVIOUSLY WEAKENED THE STEERING STR HAS SINCE PASSED TO THE
NORTHEAST ALLOWING FOR THE STR TO BUILD BACK IN OVER THE SYSTEM.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS 12W IS FORECAST TO MAINTAIN A WESTWARD TRACK ALONG THE
SOUTHERN PERIPHERY OF THE STR, WITH TRACK SPEEDS REMAINING LOW DUE
TO THE THINNING OF THE STR BY A SERIES OF MID-LATITUDE TROUGHS
TRANSITING TO THE NORTH OF THE STR. IMPROVING UPPER-LEVEL OUTFLOW
WILL HELP TO INTENSIFY THE SYSTEM OVER THE NEXT 36 HOURS. LANDFALL
IS EXPECTED JUST AFTER TAU 36. INCREASING FRICTIONAL EFFECTS ON THE
LLCC WILL QUICKLY BEGIN TO DISSIPATE THE SYSTEM, WITH STEADY
WEAKENING EXPECTED THROUGH TAU 72. THERE IS HIGH CONFIDENCE IN THIS
PORTION OF THE TRACK FORECAST BASED ON THE TIGHT MODEL ENVELOPE AND
SYNOPTIC ANALYSIS.
   C. TS 12W WILL HAVE DISSIPATED OVERLAND BY TAU 96. A REMNANT LOW
PRESSURE SYSTEM ASSOCIATED WITH TS 12W MAY GET ABSORBED INTO A DEEP
LONG-WAVE TROUGH AND EMERGE OFF THE COAST OF EASTERN CHINA AS A MID-
LATITUDE LOW PRESSURE SYSTEM. NUMERICAL MODEL GUIDANCE IS IN GOOD
AGREEMENT TO THE POINT OF LANDFALL WITH THE EXCEPTION OF THE RIGHT
MOST OUTLIER, ECMWF. THE MODEL SPREAD VARIES IN THE TRACKERS WHEN
TS 12W IS OVERLAND BUT THE DEEP TROUGH MENTIONED PREVIOUSLY SHOULD
BE ABLE TO PICK THE REMNANTS OF THE DISSIPATED SYSTEM UP BY THIS
TIME. THERE IS LOW TRACK CONFIDENCE DURING THIS PORTION OF THE
FORECAST DUE TO COMPLEX LAND INTERACTION AND TIMING OF THE TROUGH.//
NNNN
NNNN