WTPN21 PGTW 120730
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
070 NM EITHER SIDE OF A LINE FROM 30.8N 123.2E TO 31.8N 126.3E
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 120730Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 30.9N 123.4E. THE SYSTEM IS MOVING NORTH-NORTHWESTWARD AT 02
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 92W), STILL LOCATED NEAR 
30.9N 123.4E, IS APPROXIMATELY 349 NM WEST-SOUTHWEST OF SASEBO, JAPAN. 
THE SYSTEM IS CURRENTLY CLASSIFIED AS A SUBTROPICAL DEPRESSION, 
GENERALLY CHARACTERIZED AS HAVING BOTH TROPICAL AND MIDLATITUDE CYCLONE 
FEATURES. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN OBSCURED, 
ELONGATED LOW LEVEL CIRCULATION WITH DEEP PERSISTENT CONVECTION BUILDING 
OVER THE CENTER. A RECENT 120116Z ASCAT-C PASS REVEALS 25-30 KNOTS ALONG 
THE NORTHERN SIDE OF THE SEMI-CIRCLE, SUPPORTED BY A RECENT SHIP 
OBSERVATION THAT IS REPORTING SUSTAINED WIND SPEEDS OF 25 KNOTS WITH 
A MSLP OF 1008MB. ENVIRONMENTAL ANALYSIS REVEALS LOW VERTICAL WIND 
SHEAR (VWS) OF 10-15 KNOTS, GOOD POLEWARD UPPER-LEVEL OUTFLOW AND 
WARM SEA SURFACE TEMPERATURES (SST) OF 29-30C. DETERMINISTIC AND 
ENSEMBLE MODELS ARE IN AGREEMENT THAT INVEST 92W WILL MAINTAIN TD 
STRENGTH OVER THE NEXT 24 TO 48 HOURS AS IT TRACKS EASTWARD INTO 
WESTERN JAPAN. FOR HAZARDS AND WARNINGS, REFERENCE THE FLEET WEATHER 
CENTER SAN DIEGO HIGH WINDS AND SEAS PRODUCT OR REFER TO LOCAL WMO 
DESIGNATED FORECAST AUTHORITY. MAXIMUM SUSTAINED SURFACE WINDS ARE 
ESTIMATED AT 28 TO 33 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO 
BE NEAR 1002 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 
130730Z.//
NNNN