WTPN21 PGTW 120300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 96W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
135 NM EITHER SIDE OF A LINE FROM 5.6N 143.7E TO 8.1N 138.2E
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 15 TO 20 KNOTS. METSAT
IMAGERY AT 121200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 5.6N 143.7E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 11
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 96W) PREVIOUSLY LOCATED
NEAR 5.2N 144.7E IS NOW LOCATED NEAR 5.6N 143.7E APPROXIMATELY 407NM
SOUTHEAST FROM YAP. A LONGITUDINAL AND CHAOTIC DUAL-CLUSTER OF
PERSISTENT CONVECTION HAS STARTED TURNING WITH A POORLY DEFINED LOW
LEVEL CIRCULATION (LLC). CURRENT ANALYSIS INDICATES THE SYSTEM IS
TILTED WITH HEIGHT TO THE NORTH ALONG THE MOST POTENT CONVECTION
WHILE THE LOW LEVELS REMAIN AMBIGUOUS AND ELONGATED. A RECENT
PARTIAL 112352Z ASCAT PASS SHOWS A 20-25 KNOT BAND OF WINDS TO THE
NORTHWEST OF THE POORLY DEFINED LLC. THE ENVIRONMENTAL OUTLOOK FOR
96W IS FULL OF PROMISE WITH WARM SEA SURFACE TEMPERATURES (29-30 C),
WEAK VERTICAL WIND SHEAR (05-10 KTS) AND BURGEONING RADIAL OUTFLOW.
THE GLOBAL MODELS AGREE -WITH ECMWF JUMPING ON THE DEVELOPMENT
BANDWAGON- THAT THE SYSTEM WILL INTENSIFY IN THE NEXT 24 HOURS AND
TRACK WEST. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO
20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007
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
130300Z.
//
NNNN
(1) THE AREA OF CONVECTION (INVEST 96W) PREVIOUSLY LOCATED
NEAR 5N 149.3E IS NOW LOCATED NEAR 5.0N 145.9E, APPROXIMATELY 385 NM
WEST-SOUTHWEST OF CHUUK, FSM. THE POSITION WAS MOVED APPROXIMATELY
200 NM TO THE WEST BASED ON ANALYSIS OF ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) AND A RECENT ASCAT PASS. THESE DATA REVEAL A
BROAD LOW LEVEL CIRCULATION (LLC) BECOMING ESTABLISHED WITHIN AN
AREA OF SURFACE TROUGHING WITH DISORGANIZED, YET PERSISTENT
CONVECTION IN THE WESTERN PERIPHERY. ENVIRONMENTAL ANALYSIS
INDICATES THAT THE CONDITIONS FOR TROPICAL CYCLONE
DEVELOPMENT ARE FAVORABLE SUPPORTED BY VERY WARM SEA SURFACE
TEMPERATURES (29-30C), LOW TO MODERATE (10-15KTS) VERTICAL WIND
SHEAR, AND FAIR POLEWARD OUTFLOW. GLOBAL MODELS ARE IN AGREEMENT
THAT THE SYSTEM WILL CONTINUE TO DEVELOP OVER THE NEXT 36
TO 48HRS WITH GFS BEING THE MOST AGGRESSIVE. IN ADDITION, THE SYSTEM
IS TRACKING NORTH-NORTHWESTWARD. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1006 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO
MEDIUM.
(2) THE AREA OF CONVECTION (INVEST 96W) PREVIOUSLY LOCATED
NEAR 4.6N 142.4E IS NOW LOCATED NEAR 5.7N 149.8E, APPROXIMATELY 156
NM SOUTHWEST OF CHUUK . ANIMATED ENHANCED MULTISPECTRAL IMAGERY
(MSI) DEPICTS FLARING CONVECTION SURROUNDING A WEAK BROAD LOW LEVEL
CIRCULATION (LLC). ENVIRONMENTAL ANALYSIS INDICATES A FAVORABLE
ENVIRONMENT FOR DEVELOPMENT WITH STRONG POLEWARD OUTFLOW, LOW TO
MODERATE (10-15KT) VERTICAL WIND SHEAR, AND WARM (29-30C) SEA
SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 96W
WILL FOLLOW A WESTWARD TRACK AS IT INTENSIFIES. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1006MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS REMAINS LOW.
