jrchang5

JTWC 25/06Z再度對此系統評級Medium，看好未來重新發展。

(1) AN AREA OF CONVECTION (REMNANTS OF TC 19P) HAS PERSISTED
NEAR 17.2S 135.9E, APPROXIMATELY 180 NM WEST OF MORNINGTON ISLAND,
AUSTRALIA. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A
242110Z SSMIS 91GHZ IMAGE DEPICT THAT THE SYSTEM IS MAINTAINING ITS
ORGANIZATION DESPITE BEING OVER LAND, WITH FLARING DEEP CONVECTION
ALONG THE NORTHERN PERIPHERY OF A LOW LEVEL CIRCULATION CENTER (LLCC)
AND LOW LEVEL BANDING WRAPPING INTO THE LLCC. THE REMNANTS OF TC 19P
ARE EXPERIENCING FAVORABLE UPPER LEVEL CONDITIONS FOR DEVELOPMENT WITH
GOOD POLEWARD OUTFLOW AND LOW TO MODERATE (10-20KTS) VERTICAL WIND
SHEAR. GLOBAL MODELS ARE IN GENERAL AGREEMENT THAT THE REMNANTS OF TC
19P WILL CONTINUE WESTWARD ACROSS WESTERN AUSTRALIA WHERE THE
DISTURBANCE WILL REACH THE COASTLINE AND QUICKLY INTENSIFY AS IT
TRAVELS OVER VERY WARM (30-32 DEGREES CELSIUS) WATER. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS
IS MEDIUM.

ben811018

深入內陸~很會XD

ben811018

史上罕見！在陸地上生成的颱風？
是的，您沒看錯
這是本週澳洲的風場預測
位於南半球的澳洲現在正值颱風季
而這裡正在上演一場史上罕見的「陸上颱風生成秀」

故事要從昨天(2/24)開始說起，
昨天凌晨，熱帶氣旋Esther在澳洲北部的卡奔塔利亞灣(Gulf of Carpentaria)的沿岸形成，
形成後很快地朝澳洲陸地移動，並在昨天下午登陸，
隨後減弱為熱帶性低氣壓，

但是Esther的雲系殘骸並未散去，
從衛星雲圖上還是可以看到雲系明顯呈現順時鐘的排列，
仍在澳洲的北方陸地，緩慢朝西邊前進。
目前主流的數值預報(EC、GFS)皆指出：
Esther會在接近澳洲西北側沿岸的途中逐漸增強，
最大強度甚至有機會達到中度颱風以上！(昨天還預測會達強烈颱風)
且出海以後有可能在澳洲西北側近岸滯留長達數天
這樣除了狂風暴雨外，還有海水倒灌和風暴潮等問題...
直到下週Esther才會再次登陸澳洲，並深入內陸後減弱。

為什麼颱風到了陸地上沒有減弱，反而還增強呢？
當颱風的雨水下到地表後，
因為地表溫度太高（這陣子澳洲北部維持3、40度的高溫），
或是土壤中的水分已經達到飽和，
這時候溼熱的陸地就跟熱帶海洋很像，
所以雨水又馬上再蒸發回去變成颱風養分，
使得颱風不但沒減弱反而增強。
這就是Brown ocean effect，
中文直翻的話就叫它「棕色海洋效應」吧

此外，澳洲北方的陸地相當平坦，
大多數的熱帶氣旋登陸後減弱速度很慢，
這個效應才有顯著的影響，
除了澳洲北部以外，美國中部大平原和中國華東平原，
在極少數的情況下也會產生這種現象，
（2015年的熱帶風暴Bill登陸美國德州前，當地就已經出現大範圍的洪災，Bill登陸後仍維持其強度一段時間）

但是對於生活在中央山脈庇護下，
不管是強颱還是輕颱，颱風登陸後就解體的台灣人來說，
真的是難以想像颱風在登陸後還有辦法增強。

老農民版夜神月

EC,GFS預報路徑大幅東調,系集紛紛調為出海時間極短甚至大部分認為將不會出海
但仍看好其迴旋前後將於陸上有所發展

老農民版夜神月

JTWC27/0300Z發布TCFA

WTXS21 PGTW 270300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (REMNANTS OF TC 19P)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 15.5S 131.0E TO 14.9S 127.4E
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 30 TO 35 KNOTS. METSAT
IMAGERY AT 270000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 15.5S 130.8E. THE SYSTEM IS MOVING WESTWARD AT 06 KNOTS.
2. REMARKS:
THE AREA OF CONVECTION (REMNANTS OF TC 19P) PREVIOUSLY LOCATED NEAR
15.4S 132.0E IS NOW LOCATED NEAR 15.5S 130.8E, APPROXIMATELY 185NM
SOUTH OF DARWIN, AUSTRALIA.  MULTISPECTRAL SATELLITE IMAGERY AND A
262028Z SSMIS 91GHZ MICROWAVE IMAGE SHOW CONVECTIVE BANDING FROM THE
NORTH WRAPPING INTO A LOW LEVEL CIRCULATION (LLC). THE REMNANTS OF
TC 19P ARE EXPERIENCING FAVORABLE UPPER LEVEL CONDITIONS FOR
DEVELOPMENT WITH NEAR RADIAL OUTFLOW AND LOW (10-15KTS) VERTICAL
WIND SHEAR. THE MAJORITY OF GLOBAL MODELS ARE IN AGREEMENT THAT THE
REMNANTS OF TC 19P WILL TRACK WESTWARD ACROSS AUSTRALIA SKIRTING
ALONG THE NORTHWESTERN COAST PRIOR TO TURNING TO A SOUTHWARD TRACK.
PRIOR TO THIS SOUTHWARD TURN, THE REMNANTS OF TC 19P WILL TRACK
ALONG THE SOUTHERN COASTLINE OF THE JOSEPH BONAPARTE GULF. SPREAD IN
THE MODEL SOLUTIONS WILL IMPACT THE AMOUNT OF TIME THE REMNANTS OF
TC 19P WILL SPEND PASSING OVER WATER ALONG THE COAST AND THUS IMPACT
SYSTEM INTENSITY. THEREFORE, WITH HIGH (30-31C) SEA SURFACE
TEMPERATURES AND CONDUCIVE UPPER LEVEL SUPPORT, THE REMNANTS OF TC
19P COULD INTENSIFY AND REACH WARNING CRITERIA WITHIN THEN NEXT 24
HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 30 TO 35
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 996 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
280300Z.
//
NNNN

老農民版夜神月

JTWC一度於28/0300Z降評Medium,但於28/2200Z再度發布TCFA

WTXS21 PGTW 282200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (REMNANTS OF TC 19P)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
060 NM EITHER SIDE OF A LINE FROM 15.6S 125.3E TO 17.2S 123.1E
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 30 TO 35 KNOTS. METSAT
IMAGERY AT 281800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 15.7S 125.1E. THE SYSTEM IS MOVING WESTWARD AT 08 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (REMNANTS OF TC 19P) PREVIOUSLY
LOCATED NEAR 16.4S 112.5E IS NOW LOCATED NEAR 15.7S 125.1E,
APPROXIMATELY 387 NM WEST-SOUTHWESTWARD OF DARWIN, AUSTRALIA.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 281643Z AMSR2 89GHZ
MICROWAVE IMAGE DEPICT TIGHTLY CURVED CONVECTIVE BANDING WRAPPING
INTO A LOW LEVEL CIRCULATION CENTER (LLCC). THE REMNANTS OF TC 19P
ARE EXPERIENCING FAVORABLE UPPER LEVEL CONDITIONS WITH NEAR RADIAL
OUTFLOW AND LOW TO MODERATE (10-20 KTS) VERTICAL WIND SHEAR. GLOBAL
MODELS AGREE THAT THE REMNANTS OF TC 19P WILL CONTINUE TO TRACK
WESTWARD TOWARD THE NORTHWESTERN AUSTRALIAN COAST, TURNING SOUTH-
SOUTHEASTWARD BEFORE THE LOW LEVEL CIRCULATION TRACKS OVER WARM (30-
31C) WATER. IF THE REMNANTS CONTINUE TO TRACK OVER WATER, 19P WILL
LIKELY INTENSIFY TO A TROPICAL CYCLONE. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 30 TO 35 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 996 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
292200Z.//
NNNN

jrchang5

JTWC 29/22Z取消TCFA，並降評為Low。

WTXS21 PGTW 292200
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (REMNANTS OF TC 19P)
CANCELLATION//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/282151Z FEB 20//
AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW 282200)//
RMKS/
1. REMARKS: THIS CANCELS REF A (WTXS21 PGTW 282200). THE AREA OF
CONVECTION (REMNANTS OF TC 19P) PREVIOUSLY LOCATED NEAR 17.5S 123.4E
IS NOW LOCATED NEAR 18.1S 123.6E, APPROXIMATELY 538 NM SOUTHWEST OF
DARWIN, AUSTRALIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A
291726Z AMSR2 89GHZ MICROWAVE IMAGE DEPICT TIGHTLY CURVED CONVECTIVE
BANDING WRAPPING INTO A LOW LEVEL CIRCULATION CENTER (LLCC). THE
REMNANTS OF TC 19P ARE EXPERIENCING MARGINAL UPPER LEVEL CONDITIONS
WITH NEAR RADIAL OUTFLOW OFFSET BY MODERATE TO HIGH (15-25 KTS)
VERTICAL WIND SHEAR. GLOBAL MODELS GENERALLY AGREE THE REMNANTS OF
19P WILL CONTINUE ON A SOUTH-SOUTHEASTERLY TRACK OVER LAND AS IT
WEAKENS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 998 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS DOWNGRADED TO LOW. THIS CANCELS REF A.//
NNNN

老農民版夜神月

JTWC01/1800Z取消評級,數值預報其將繼續深入內陸直至消亡

  (1) THE AREA OF CONVECTION (REMNANTS OF TC 19P) PREVIOUSLY
LOCATED NEAR 17.5S 123.4E HAS DISSIPATED AND IS NO LONGER SUSPECT
FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE IN THE NEXT
24 HOURS.