WTPN21 PGTW 171430
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 92W)//
RMKS/ 
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 100 NM 
OF EITHER SIDE OF A LINE FROM 21.5N 127.1E TO 25.3N 127.3E WITHIN THE 
NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFYISSUANCE OF NUMBERED 
TROPICAL CYCLONE WARNINGS AT THIS TIME.WINDS IN THE AREA ARE ESTIMATED 
TO BE 18 TO 23 KNOTS. METSATIMAGERY AT 081712Z INDICATES THAT A 
CIRCULATION CENTER IS LOCATEDNEAR 21.6N 127.1E. THE SYSTEM IS MOVING 
NORTH-NORTHEASTWARD AT 03 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 92W) PREVIOUSLY LOCATED NEAR 
21.2N 127.7E IS NOW LOCATED NEAR 21.5N 127.1E, APPROXIMATELY 283 NM 
SOUTH OF KADENA AFB. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY 
DEPICTS A QUICKLY CONSOLIDATING AND A PARTIALLY EXPOSED LOW LEVEL 
CIRCULATION CENTER (LLCC), EMBEDDED WITHIN A REVERSE ORIENTED MONSOON 
TROF. FLARING CONVECTION ALONG THE EASTERN PERIPHERY OF THE CIRCULATION 
HAS BEGUN TO CONSOLIDATE INTO FORMATIVE BANDING. A 171235Z ASCAT-B PASS 
SHOWED A FORMATIVE LLCC TO THE WEST OF AN EXTENSIVE REGION OF 20-25 KNOT 
WINDS EXTENDING ALONG THE ENTIRE EASTERN HALF OF THE CIRCULATION, WITH 
SOME EMBEDDED WINDS OF 30 KNOTS ISOLATED IN THE NORTHEASTERN QUADRANT. 
ANIMATED WATER VAPOR IMAGERY INDICATES A TUTT-CELL POSITIONED 
APPROXIMATELY 200NM NORTH OF 92W, WHICH HAS BEGUN TO ENHANCE THE 
POLEWARD OUTFLOW, AND SUPPORTING CONVECTIVE DEVELOPMENT IN AND AROUND 
THE LLCC. ENVIRONMENTAL ANALYSIS FOR THE AREA INDICATES FAVORABLE 
CONDITIONS FOR DEVELOPMENT WITH LOW VERTICAL WIND SHEAR (5-10 KTS), WARM 
SEA SURFACE TEMPERATURES (30 C) AND GOOD POLEWARD OUTFLOW ALOFT ONLY 
OFFSET BY DRY MID-LEVEL AIR TO THE NORTH DUE TO THE AFOREMENTIONED TUTT 
CELL. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 92W WILL TRACK NORTHWARD 
AND SLOWLY INTENSIFY OVER THE NEXT 24 HOURS. 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 
181430Z.
//
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