WDPN31 PGTW 222100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 08W (KUJIRA) WARNING NR
10//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 08W (KUJIRA), LOCATED APPROXIMATELY 248 NM
EAST-SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED NORTHWESTWARD AT 06
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS DEEP CONVECTION WITH A CURVED NOTCH ALONG
THE EASTERN EDGE INDICATING THE LOCATION OF THE LOW LEVEL
CIRCULATION CENTER (LLCC). THE CURRENT POSITION IS BASED ON THE
NOTCH IN THE EIR LOOP AND SUPPORTED BY THE 221732Z PGTW SATELLITE
FIX WITH GOOD CONFIDENCE. THE INITIAL INTENSITY OF 35 KNOTS IS BASED
ON THE CURRENT STRUCTURE OF THE SYSTEM AND IS SUPPORTED BY RECENT
OBSERVATIONS RANGING FROM 31 TO 33 KNOTS AT SANYA FENGHUANG (ZJSY),
CHINA (SOUTHEASTERN COAST OF HAINAN). UPPER LEVEL ANALYSIS INDICATES
THE SYSTEM REMAINS IN A MARGINAL TO POOR ENVIRONMENT WITH MODERATE
TO HIGH (20-30 KNOT) VERTICAL WIND SHEAR (VWS) BEING PARTIALLY
OFFSET BY DECENT DIFFLUENCE ALOFT. TS KUJIRA IS TRACKING
NORTHWESTWARD UNDER THE STEERING INFLUENCE OF AN EXTENSION OF THE
SUB-TROPICAL RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
B. TS KUJIRA WILL CONTINUE ON A NORTHWESTWARD TRAJECTORY UNDER
THE STEERING INFLUENCE OF THE STR TO THE EAST THROUGHOUT THE
FORECAST PERIOD. TS 08W WILL GRADUALLY WEAKEN AS IT CROSSES HAINAN
ISLAND AND ENTERS THE GULF OF TONKIN. WARM SEA SURFACE TEMPERATURES
AND DECREASED VWS WILL ALLOW THE SYSTEM TO MAINTAIN INTENSITY BEFORE
MAKING A SECOND LANDFALL OVER THE SOUTHERN COAST OF CHINA, WHERE IT
WILL FULLY DISSIPATE BY THE END OF THE FORECAST PERIOD. AVAILABLE
MODEL GUIDANCE REMAINS IN GOOD AGREEMENT LEADING TO HIGH CONFIDENCE
IN THE JTWC FORECAST TRACK.//
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