WTXS21 PGTW 192000
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 93S)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
055 NM EITHER SIDE OF A LINE FROM 3.9S 55.6E TO 5.2S 53.7E 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 28 TO 33 KNOTS. METSAT IMAGERY AT
191800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 3.9S
55.5E. THE SYSTEM IS MOVING WESTWARD AT 05 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 93S) PREVIOUSLY LOCATED NEAR
3.2S 57.1E IS NOW LOCATED NEAR 3.9S 55.5E, APPROXIMATELY 47 NM NORTH OF
SEYCHELLES. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) DEPICTS
AN AREA OF BROAD BUT CONSOLIDATING TURNING ON THE NORTHEASTERN SIDE OF
FLARING CONVECTION. A 091530Z SSMIS 91GHZ PASS REVEALS INTENSE DEEP
CONVECTION ON THE SOUTHWESTERN PERIPHERY OF 93S, WITH BROAD AND
ASYMMETRIC, BUT DEFINED, FORMATIVE LOW-LEVEL CLOUD BANDS WRAPPING UNDER
THE CONVECTION. A 191724Z METOP-C ASCAT PASS REVEALS ENHANCED WINDS
ALONG THE SOUTHERN PERIPHERY OF THE ASYMMETRIC CIRCULATION CENTER.
ENVIRONMENTAL ANALYSIS REVEALS LOW TO MODERATE VERTICAL WIND SHEAR (15-
20KTS), WARM SEA SURFACE TEMPERATURES (28-29C), AND MODERATE RADIAL
OUTFLOW ALOFT. GLOBAL DETERMINISTIC AND ENSEMBLE MODELS ARE IN AGREEMENT
IN THE GRADUAL DEVELOPMENT OF 93S, THOUGH DETERMINISTIC MODELS ARE MORE
CONSERVATIVE THAN THE ENSEMBLES. 93S IS EXPECTED TO TRANSIT GENERALLY
SOUTHWESTWARD AS IT CONSOLIDATES. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 28 TO 33 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO
BE NEAR 998 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
202000Z.//
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