南太平洋熱帶氣旋20P(Amos)巔峰風速(90kts)維持將近30小時，今天(24日)起終於因為西風急流造成環境風切大幅增強，已呈現對流切離、快速減弱的狀態。

Amos發展初期底層風眼迅速建立，然而高層風眼遲遲沒有開啟，無法朝更高強度邁進。昨天(23日)Amos嚴重影響薩摩亞(Somas)，儘管中心從北方近海通過且強度沒有進一步再提升，仍造成不少風毀、淹水與道路中斷的災情。





以下為巔峰雲圖與Somas當地災情 (災情圖片取自 Disaster Management Office - Samoa)

JTWC 09Z分析T4.5 評價75節 巔峰上望Cat.3 (105kts)




高層風眼建立中 趁南落以前 藉良好高空幅散有爆發增強的機會

00z升評價65kts 升格cat1 底層畫質奇差都看的出已經建立





目前環境各方面還不錯 幅散 海溫都良
但南方風切非常強 發展時間估計還剩一天多

13Z命名Amos

TROPICAL DISTURBANCE ADVISORY NUMBER A5 ISSUED FROM RSMC NADI
Apr 201349 UTC.

TROPICAL CYCLONE AMOS CENTRE 995HPA WAS LOCATED NEAR 12.8S 179.8W AT
201200UTC. POSITION FAIR BASED ON HIMAWARI-8 IMAGERY AND PERIPHERAL
SURFACE REPORTS. AMOS MOVING WEST-SOUTHWEST AT ABOUT 04 KNOTS.
MAXIMUM 10-MINUTE AVERAGE WINDS NEAR THE CENTRE ESTIMATED AT ABOUT 35
KNOTS.EXPECT SUSTAINED WINDS OF 35 KNOTS CLOSE TO THE CENTRE.

DEEP CONVECTION REMAINS PERSISTENT WITH BAND TRYING TO WRAP AROUND
LLCC. ORGANISATION HAS IMPROVED IN LAST 24 HOURS. CYCLONIC
CIRCULATION EXTENDS UP TO 500HPA. SYSTEM LIES IN A MODERATE UPPER
DIVERGENCE REIGION AND IN A LOW SHEARED ENVIRONMENT. SST AROUND 30
DEGREE CELCIUS.OUTFLOW GOOD TO THE SOUTH. DVORAK ANALYSIS BASED ON
0.55-0.6 WRAP YIELDS DT=3.0, MET AND PT AGREE. FT BASED ON DT. THUS,
YIELDING T3.0/3.0/D1.5/24HRS.

FORECASTS :
AT 12 HRS VALID AT 210000 UTC 12.8S 179.9E MOV W AT 02KT WITH 40 KT
CLOSE TO CENTRE
AT 24 HRS VALID AT 211200 UTC 12.6S 179.7W MOV ENE AT 02KT WITH 50 KT
CLOSE TO CENTRE.

OUTLOOK:
AT 36 HRS VALID AT 220000 UTC 12.3S 178.8W MOV ENE AT 05KT WITH 55 KT
CLOSE TO CENTRE
AT 48 HRS VALID AT 221200 UTC 12.3S 177.4W MOV E AT 06KT WITH 60 KT
CLOSE TO CENTRE.

THE NEXT TOPICAL DISTURBANCE ADVISORY ON AMOS WILL BE ISSUED AROUND
202000UTC.