WTPN21 PGTW 190930
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91W)//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/190922Z JUL 24//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT (WTPN22 PGTW 
190930)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
150 NM EITHER SIDE OF A LINE FROM 13.9N 118.3E TO 17.7N 112.4E
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 20 TO 25 KNOTS. METSAT
IMAGERY AT 190900Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 14.1N 118.0E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 10
KNOTS.
2. REMARKS:
THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED NEAR 13.7N 
118.0E IS NOW LOCATED NEAR 14.1N 118.0E, APPROXIMATELY 175 NM EAST OF 
MANILA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A BROAD, 
PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION (LLC) WITH FLARING DEEP 
CONVECTION SHEARED TO THE WEST. A 190124Z MHS 89GHZ MICROWAVE IMAGE 
DEPICTS CURVED BANDING OVER THE WESTERN SEMI-CIRCLE, WITH A WEAKLY 
DEFINED LLC. ENVIRONMENTAL ANALYSIS REVEALS A FAVORABLE ENVIRONMENT 
FOR FURTHER DEVELOPMENT WITH LOW (5-15KTS) VWS, GOOD POLEWARD OUTFLOW, 
AND WARM (29-30C) SSTS. GLOBAL DETERMINISTIC MODELS ARE IN GOOD 
AGREEMENT THAT INVEST 91W WILL STEER WEST-NORTHWESTWARD AS IT 
CONTINUES TO SLOWLY STRENGTHEN OVER NEXT 48 HOURS. MAXIMUM SUSTAINED 
SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL 
PRESSURE IS ESTIMATED TO BE NEAR 1004 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 
200930Z.
4. SEE REF A FOR DETAILS ON A TROPICAL CYCLONE FORMATION ALERT
LOCATED NEAR 12.5N 132.4E.//
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