WTPS21 PGTW 060930
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
200 NM EITHER SIDE OF A LINE FROM 17.4S 178.8W TO 22.8S 169.1W
WITHIN THE NEXT 06 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 25 TO 30 KNOTS. METSAT IMAGERY AT
060900Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 17.4S
178.1W. THE SYSTEM IS MOVING EASTWARD AT 10 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 17.1S
178.8W IS NOW LOCATED NEAR 17.4S 178.1W, APPROXIMATELY 255 NM EAST
OF NADI, FIJI. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS A RAPIDLY
CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH TIGHTLY-
CURVED BANDING (TCB) WRAPPING INTO THE CENTER. A 060516Z SSMIS 37GHZ
IMAGE ALSO DEPICTS TCB AND A WELL-DEFINED LLCC. THE SYSTEM HAS
ORGANIZED QUICKLY SINCE CROSSING FIJI AND IS EMBEDDED WITHIN A
GENERALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY WEAK VERTICAL WIND
SHEAR AND STRONG DIFFLUENCE ALOFT. ALTHOUGH SURFACE WINDS AT NFFN
PEAKED AT ONLY 15 KNOTS, SLP VALUES AS LOW AS 995MB WERE OBSERVED.
THE SYSTEM IS LOCATED ALONG THE TAIL-END OF A SHEAR LINE AND MODEL
GUIDANCE IS POORLY INITIALIZED; HOWEVER, DYNAMIC MODEL GUIDANCE
SUPPORTS AN EAST-SOUTHEASTWARD TRACK. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 25 TO 30 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
070930Z.//