Westernpacificweather.com - NEW TROPICAL SYSTEM 99W QUICKLY UPGRADED BY JMA…JTWC ISSUES TCFA

NEW TROPICAL SYSTEM 99W QUICKLY UPGRADED BY JMA…JTWC ISSUES TCFA

Published on August 2, 2012 by Voxianguy in Breaking News, Storm Update, Tropicals

An area of disturbed weather designated as 99W by American forecasting agencies has been declared a tropical depression by the Japan Meteorological Agency, while the JTWC issued a Tropical Cyclone Formation Alert for this system.

The information from JMA is as follows:

<Analyses at 01/21 UTC>
Scale	-
Intensity	-
	TD
Center position	N23°25′(23.4°)
	E146°20′(146.3°)
Direction and speed of movement	Almost stationary
Central pressure	1002hPa
Maximum wind speed near the center	15m/s(30kt)
Maximum wind gust speed	23m/s(45kt)

The JTWC offers the following information:

1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 165 NM EITHER SIDE OF A LINE FROM 23.3N 145.9E TO 24.2N 140.8E 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 18 TO 23 KNOTS. METSAT IMAGERY AND SYNOPTIC DATA AT 012200Z INDICATE THAT A CIRCULATION CENTER IS LOCATED NEAR 23.4N 145.3E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 07 KNOTS.2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 22.3N 145.5E IS NOW LOCATED NEAR 23.4N 145.3E, APPROXIMATELY 230 NM EAST-SOUTHEAST OF IWO-TO, JAPAN. ANIMATED MULTISPECTRAL SATELLITE IMAGERY(MSI) INDICATES AN ORGANIZED, EXPOSED, SYMMETRIC LOW LEVEL CIRCULATION CENTER (LLCC) DISPLACED 120 NM WEST OF A CURVED BAND OF DEEP CONVECTION. MSI ALSO SHOWS AN EXTENSIVE AREA OF INTENSE CONVECTION ASSOCIATED WITH STRONGLY CONVERGENT WESTERLY SURFACE FLOW. RECENT SHIP OBSERVATIONS OVER THE SOUTHERN SEMI-CIRCLE INDICATE CONVERGENT WESTERLY WINDS OF 22-26 KNOTS WITH SLP VALUES RANGING FROM 1003-1005 MB. A 012036Z SSMIS 91GHZ IMAGE ALSO INDICATES A SLIGHTLY ELONGATED BUT RAPIDLY DEVELOPING LLCC WITH WELL-DEFINED SHALLOW CONVECTIVE BANDING. RECENT TOTAL PRECIPITABLE WATER IMAGERY SHOWS A WELL-DEFINED LLCC WITH A CONSOLIDATING, DEEP MOISTURE ENVELOPE. RECENT ANIMATED WATER VAPOR IMAGERY DEPICTS INCREASING POLEWARD OUTFLOW INTO THE TROPICAL UPPER TROPOSPHERIC TROUGH AND FAVORABLE EQUATORWARD OUTFLOW; HOWEVER, THE GOOD OUTFLOW IS OFFSET SOMEWHAT BY STRONG (30-40 KNOTS) NORTHWESTERLY VERTICAL WIND SHEAR (VWS). DYNAMIC MODELS INDICATE THE SYSTEM WILL DEVELOP QUICKLY AS VWS DECREASES WITHIN THE NEXT 24 HOURS. SYSTEM IS EXPECTED TO TRACK WESTWARD TOWARD OKINAWA. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23 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.