92W TCFA - 颱風討論

https://www.metoc.navy.mil/jtwc/products/wp9219web.txt
https://www.metoc.navy.mil/jtwc/products/wp9219.gif

WTPN22 PGTW 311930
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 92W)//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/311851Z AUG 19//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT (WTPN21 PGTW
311900)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 8.8N 131.4E TO 15.8N 125.3E
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 18 TO 23 KNOTS. METSAT
IMAGERY AT 311800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 9.5N 130.7E. THE SYSTEM IS MOVING NORTH-NORTHWESTWARD AT 12
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 92W) PREVIOUSLY LOCATED
NEAR 6.9N 134.0E, IS NOW LOCATED NEAR 9.5N 130.7E, APPROXIMATELY 332
NM EAST-NORTHEAST OF DAVAO CITY, THE PHILIPPINES. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY DEPICTS AMPLE FLARING CONVECTION OVER A
BROAD LOW LEVEL CIRCULATION. THE ENVIRONMENT REMAINS OVERALL
FAVORABLE, WITH WARM (29-31C) SEA SURFACE TEMPERATURES, MODERATE (10-
20 KNOT) VERTICAL WIND SHEAR, AND STRONG DIVERGENCE ALOFT DUE TO
FORMATIVE RADIAL OUTFLOW. GLOBAL MODELS ALL SHOW DEVELOPMENT AS THE
SYSTEM TRACKS NORTHWEST ALONG THE PHILIPPINE COAST, HOWEVER THE
ECMWF AND UKMO DELAY THE ONSET OF 25 KNOT WINDS UNTIL CLOSER TO THE
48 HOUR MARK. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO
23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005
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
011930Z.
4. SEE REF A FOR DETAILS ON A TROPICAL CYCLONE FORMATION ALERT
LOCATED NEAR 18.8N 118.3E.//
NNNN

系統的LLCC開始明顯有深層對流覆蓋，
目前位於攝氏29~31度的海溫，10~20kts的垂直風切，並呈現輻射狀的優秀流出
全球模式認為系統在接近菲律賓沿海會明顯發展，
但ECMWF和UKMO預測則遲至接近48小時後才會發展至25kts的強度，
此為JTWC認為現有的資料不完全支持在此時發出TCFA的原因。



台灣風季未來一週的觀察重點，除了和副高與91W的互動，
在91W日前已發出TCFA和GW的狀況下，誰會搶到玲玲也是值得關注的部分。

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