WTPN21 PGTW 110530
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 98W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
A 245 NM RADIUS OF 16.0N 124.7E WITHIN THE NEXT 12 TO 24 HOURS.
AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL
CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO
BE 18 TO 23 KNOTS. METSAT IMAGERY AT 101100Z INDICATES THAT A
CIRCULATION CENTER IS LOCATED NEAR 16.0N 124.7E. THE SYSTEM IS
MOVING WESTWARD AT 04 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 98W) PREVIOUSLY LOCATED NEAR 
16.2N 124.5 IS NOW LOCATED NEAR 16.0N 124.7E, APPROXIMATELY 331 NM ENE OF 
MANILA, PHILIPPINES. ENHANCED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND 
SCATTEROMETRY DATA DEPICT A WELL-ROUNDED LOW LEVEL CIRCULATION TUCKED 
BENEATH THE SOUTHEAST SIDE OF INTENSE BUT DISORGANIZED CONVECTION WHICH 
HAS PERSISTED FOR THE PAST FOUR HOURS. A 110112Z ASCAT METOP-C PARTIAL 
PASS SHOWED 30-35KT NORTHERLY WINDS ASSOCIATED WITH A NE SURGE EVENT, 
SURGING DOWN FROM THE LUZON STRAIGHT, AND 20-25KTS WINDS ON THE EAST SIDE 
OF LUZON BEGINNING TO WRAP TO THE SOUTHWEST OF THE LLCC. WINDS ON THE 
EASTERN SIDE OF THE CIRCULATION ARE MUCH LOWER, IN THE 10-15 KNOT RANGE 
BASED ON EARLIER SCATTEROMETER DATA. ANALYSIS REVEALS A SMALL UPPER-LEVEL 
ANTICYCLONE DIRECTLY OVER TOP OF THE LOW LEVEL CIRCULATION, PROVIDING 
GOOD RADIAL OUTFLOW AND LOW VERTICAL WIND SHEAR (10-15 KNOTS), WITH 
SUPPORTIVELY WARM SSTS (30-31C). MODEL GUIDANCE SHOWS THE SYSTEM DRIFTING 
SLOW TOWARDS THE WEST BUT REMAINING EAST OF LUZON, BLOCKED BOTH BY THE 
TERRAIN OF LUZON ITSELF AND THE STRONG NE SURGE FLOW ACTING AS A BARRIER. 
THE MODEL TRACKERS JUMP CIRCULATIONS AFTER ABOUT TAU 36, INTO THE SOUTH 
CHINA SEA INTO A SEPARATE AND DISTINCT AREA OF VORTICITY. THUS THE 
GUIDANCE IS UNRELIABLE AT THIS POINT, ESPECIALLY BEYOND ABOUT 36 HOURS. 
UP TO THAT POINT THE BULK OF THE INTENSITY GUIDANCE SUGGESTS A BRIEF 
WINDOW OF OPPORTUNITY FOR THE SYSTEM TO DEVELOP BUT THEN DEPICTS 
WEAKENING AND ULTIMATE DISSIPATION AFTER TAU 36 TO THE EAST OF LUZON.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 
120530Z.
//
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