92W TCFA - 颱風討論

https://www.metoc.navy.mil/jtwc/products/wp9220web.txt
https://www.metoc.navy.mil/jtwc/products/wp9220.gif

WTPN21 PGTW 091100
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
140 NM EITHER SIDE OF A LINE FROM 13.1N 116.2E TO 14.7N 113.1E
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 15 TO 20 KNOTS. METSAT
IMAGERY AT 090900Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 13.1N 115.6E. THE SYSTEM IS MOVING WESTWARD AT 18 KNOTS.
2. REMARKS: THE AREA ON CONVECTION (INVEST 92W) PREVIOUSLY LOCATED
NEAR 13.1N 117.4E IS NOW LOCATED NEAR 13.1N 115.6E, APPROXIMATELY
NEAR 13.1N 117.4E IS NOW LOCATED NEAR 13.1N 115.6E, APPROXIMATELY
466 NM EAST-SOUTHEAST OF DANANG, VIETNAM. ANIMATED ENHANCED
INFRARED (EIR) SATELLITE IMAGERY DEPICTS FLARING CONVECTION WITH
LOW LEVEL BANDING WRAPPING INTO A PARTIALLY OBSCURED LOW LEVEL
CIRCULATION CENTER (LLCC). THE FORMATIVE BANDS ARE ALSO PRESENT
IN A 090525Z ATMS 183GHZ IMAGE WHICH FURTHER CONSTRAINS THE CURRENT
POSITION. INVEST 92W IS CURRENTLY TRACKING THROUGH AN ENVIRONMENT
THAT IS MARGINALLY FAVORABLE FOR FURTHER DEVELOPMENT WITH MODERATE
(15-25 KTS) VERTICAL WIND SHEAR (VWS) OFFSET BY WARM (28-30
CELSIUS) SEA SURFACE TEMPERATURES (SST) AND ROBUST EQUATORWARD
OUTFLOW ALOFT. NUMERICAL MODELS ARE IN FAIR AGREEMENT THAT INVEST
92W WILL CONTINUE TO TRACK GENERALLY WESTWARD OVER THE NEXT 24
HOURS AND CONTINUE TO CONSOLIDATE AS THE VWS WEAKENS BELOW 15 KTS.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 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 101100Z.//
NNNN


LLCC開始有部分對流覆蓋，目前位處的環境條件包含
15~25kts的垂直風切，攝氏28~30度的海溫，以及強大的赤向留出，因此發出TCFA。
多數的數值預報一致認為系統未來24小時仍以較慢的速度維持平西。

雖然不會直接影響台灣，但登陸越南後是否會因此有南方水氣移入，
以及會不會因此影響菲東雲團的路徑，是未來一週的觀察重點之一。

--