徹評後大約兩小時,1430Z左右,FNMOC隨即撤編98S
JTWC官方定強定位也停在0600Z,1200Z一報時即不再對此系統做出分析
NRL則在2203Z(4月15日凌晨6時)左右撤編

98S INVEST 190414 0600 21.6S 114.6E SHEM 20 1008

JTWC 14/1230Z取消評級。

(1) THE AREA OF CONVECTION (INVEST 98S) PREVIOUSLY LOCATED
NEAR 19.8S 113.9E, HAS DISSIPATED AND IS NO LONGER SUSPECT FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE IN THE NEXT 24 HOURS.

JTWC 13/18Z降評為Low。

(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 18.1S
117.4E, IS NOW LOCATED NEAR 19.8S 113.9E, APPROXIMATELY 140 NM NORTH
OF LEARMONTH, AUSTRALIA. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY AND A 131346Z MHS METOP-A 89GHZ IMAGE DEPICTS A FULLY-
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH WEAK, FLARING
CONVECTION BEING SHEARED TO THE EAST. DESPITE THE STRONG VERTICAL
WIND SHEAR (VWS), THE LOW LEVEL STRUCTURE IS WELL ORGANIZED WITH
SPIRAL BANDING WRAPPING INTO THE TIGHT LLCC. INVEST 98S IS NOW UNDER
UPPER-LEVEL WESTERLIES, WHICH IS FURTHER SEPARATING THE CONVECTION
AND THE CIRCULATION. INVEST 98S WILL CONTINUE TO WEAKEN AS IT MOVES
SOUTH TOWARDS LEARMONTH, AUSTRALIA, AND IS NOT FORECAST TO ATTAIN
TROPICAL CYCLONE INTENSITY.  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 DOWNGRADED
TO LOW.

昨天接近午夜時掃出來的風場圖,掃出大片的30kt風場

JTWC隨後18Z一報便將定強由25上調30節

SH, 98, 2019041212,   , BEST,   0, 174S, 1156E,  25, 1004, TD,   0,    ,    0,    0,    0,    0, 1009,  165,  60,   0,   0,    ,   0,    ,   0,   0,     INVEST,  ,
SH, 98, 2019041218,   , BEST,   0, 181S, 1149E,  30,  999, TD,   0,    ,    0,    0,    0,    0, 1009,  165,  65,   0,   0,    ,   0,    ,   0,   0,     INVEST,  ,
SH, 98, 2019041300,   , BEST,   0, 184S, 1144E,  30, 1000, TD,   0,    ,    0,    0,    0,    0, 1011,  130,  65,   0,   0,   S,   0,    ,   0,   0,     INVEST, S,
SH, 98, 2019041306,   , BEST,   0, 192S, 1142E,  30, 1000, TD,   0,    ,    0,    0,    0,    0, 1011,  130,  65,   0,   0,    ,   0,    ,   0,   0,     INVEST,  ,

JTWC在升評Medium的報文中也特別提及ASCAT的此次風場掃描
大概率是在LLCC完全裸奔也沒有數值看好的情形下升評98SMedium的重要原因

A 121409Z ASCAT IMAGE DEPICTS A SWATH OF 30 KT GRADIENT
WINDS BEING ACCELERATED BETWEEN THE CIRCULATION AND A SURFACE HIGH
TO THE SOUTH, WITH SEVERAL 35 KT WIND BARBS WITHIN.

附上兩張不久前的雲圖對比,明顯依然在嚴重裸奔的狀態

JTWC 13/02Z提升評級至Medium，但主流數值並不看好發展。

(1) THE AREA OF CONVECTION (INVEST 98S) PREVIOUSLY LOCATED
NEAR 18.1S 117.4E, IS NOW LOCATED NEAR 18.4S 114.4E, APPROXIMATELY
225 NM NORTH OF LEARMONTH, AUSTRALIA. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY DEPICTS A FULLY-EXPOSED LOW-LEVEL CIRCULATION
CENTER (LLCC) WITH WEAK, FLARING CONVECTION BEING SHEARED OVER 125
NM TO THE EAST. DESPITE THE STRONG VERTICAL WIND SHEAR (VWS), THE
LOW LEVELS ARE WELL ORGANIZED WITH SPIRAL BANDING WRAPPING INTO THE
TIGHT LLCC. A 121409Z ASCAT IMAGE DEPICTS A SWATH OF 30 KT GRADIENT
WINDS BEING ACCELERATED BETWEEN THE CIRCULATION AND A SURFACE HIGH
TO THE SOUTH, WITH SEVERAL 35 KT WIND BARBS WITHIN. VWS IS HIGH AND
98S IS APPROACHING UPPER-LEVEL WESTERLIES, WHICH WILL BRING
CONVERGENCE ALOFT AND FURTHER SEPARATE THE CONVECTION AND THE
CIRCULATION. 98S WILL WEAKEN AS IT MOVES SOUTH TOWARDS LEARMONTH,
AUSTRALIA, AND IS NOT FORECAST TO ATTAIN TROPICAL CYCLONE INTENSITY
BY ANY MODEL. HOWEVER, THERE IS STILL THE POSSIBILITY OF STRONG
GRADIENT FLOW IN THE VICINITY OF LEARMONTH. 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 UPGRADED TO MEDIUM.

JTWC 10/18Z評級Low。

(1) AN AREA OF CONVECTION (INVEST 98S) HAS PERSISTED NEAR
12.3S 123.8E, APPROXIMATELY 350 NM NORTH-NORTHEAST OF BROOME,
AUSTRALIA. ANIMATED ENHANCED INFRARED IMAGERY DEPICTS AN AREA OF
WEAK CONVECTION BEGINNING TO WRAP INTO A CONSOLIDATING LOW LEVEL. A
101310Z METOP-A 89GHZ MHS IMAGE SHOWS SCATTERED CONVECTION STARTING
TO BECOME BETTER ORGANIZED. 98S IS CURRENTLY LOCATED IN AN AREA THAT
IS MARGINALLY FAVORABLE FOR DEVELOPMENT WITH GOOD POLEWARD OUTFLOW,
STRONG VERTICAL WIND SHEAR (20-25KTS), AND WARM SEA SURFACE
TEMPERATURES (28-29C). GLOBAL MODELS ARE IN AGREEMENT THAT THE
SYSTEM WILL FOLLOW A SOUTHWESTWARD TRACK INTO AN AREA OF LOW
VERTICAL WIND SHEAR. HOWEVER, MODELS DISAGREE ON THE EXACT
INTENSIFICATION OF THE SYSTEM AND ITS POTENTIAL FOR REACHING
TROPICAL CYCLONE STRENGTH. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 20 TO 25 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 LOW.

BoM 已編號熱帶低壓"22U"，不看好發展。

Potential Cyclones:

A weak tropical low (22U) was located north of the Gulf of Carpentaria Saturday afternoon. The environment is currently unfavourable for development but conditions could improve during the next few days and it has a Low chance of developing from Tuesday. It is forecast to move quickly west and pass over the Timor Sea or far northern Kimberley on Monday or Tuesday, which could lead to increased rainfall in the Northern Kimberley. On Wednesday and Thursday it might be near the Pilbara coast and bring some increased rainfall.


Likelihood of another system being a tropical cyclone in the Western Region on:
Sunday:Very Low
Monday:Very Low
Tuesday:Low