WNP: TY 02W(SURIGAE) still a CAT4(115knots)/ SIndian: Invest 95S: likely to intensify within the next 24hours(TCFA), 20/09utc update


02W(SURIGAE) AND INVEST 95S. 20/09UTC. 5H LOOP.


02W(SURIGAE) AND INVEST 95S. 20/09UTC. 5H LOOP.
02W(SURIGAE) AND INVEST 95S. 20/09UTC. 5H LOOP.
2021 APR 20 0855UTC #WESTERNNORTHPACIFIC
TY #02W #SURIGAE
WARNING 28
As of 06:00 UTC Apr 20, 2021:
Location: 15.9°N 126.0°E
Maximum Winds: 115 kt (215km/h)
Gusts: 140 kt ( 260km/h)
Minimum Central Pressure: 939 mb
CATEGORY US: 4
LOCATED AT 20/06UTC 555 KM EAST-NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTH-NORTHWESTWARD AT
09 KM/H OVER THE PAST SIX HOURS.
Satellite bulletins are to be found in the comments of this post on JTWC BIS
-----------------------------------------------------------------------------------------------------------
INVEST #95S #SOUTHERNHEMISPHERE #SOUTHINDIANOCEAN
TCFA
As of 06:00 UTC Apr 20, 2021:
Location: 10.8°S 52.4°E
Maximum Winds: 28/33 kt
Gusts: 40 kt ( 75km/h)
Minimum Central Pressure: 998 mb

LOCATED AT 20/06UTC APPROXIMATELY 1175 KM NORTH-NORTHWEST OF MAURITIUS. MOVING WEST-NORTHWESTWARD AT 26KM/H.
Satellite bulletins are to be found in the comments of this post on JTWC BIS

Cheers,
Patrick Hoareau
M974World
ILES SOEURS
Cyclone Class 4
 Cheers,PH.

Joint Typhoon Warning Center

02W(SURIGAE). WARNING 28 ISSUED AT 20/09UTC.TY 02W REMAINS IN A GENERALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY LOW (8-12 KTS) AND STRONG  POLEWARD AND EQUATORWARD OUTFLOW. SSTS REMAIN GENERALLY WARM, THOUGH  RECENT HYCOM MODEL ANALYSIS SUGGESTS SIGNIFICANT UPWELLING,  PRIMARILY TO THE SOUTH IN THE STORMS WAKE. HOWEVER, NOW THAT THE  SYSTEM HAS PICKED UP FORWARD SPEED ONCE MORE, IT IS MOVING AWAY FROM  THE INDUCED POOL OF COOLER WATERS AND INTO A REGION OF 27-28C  WATERS. TY SURIGAE IS FORECAST TO TRACK NORTHEASTWARD ALONG THE  WESTERN PERIPHERY OF A DEEP SUBTROPICAL RIDGE (STR) THROUGH 36H,  THEN ROUND THE RIDGE AXIS AND TURN SHARPLY NORTHEAST AHEAD OF STRONG  MID-LATITUDE SHORTWAVE TROUGH MOVING IN FROM THE WEST. BY 72H,  SURIGAE WILL BE ON A NEAR EASTWARD COURSE, STEADILY ACCELERATING AS  IT BEGINS TO INTERACT WITH THE SUBTROPICAL JET ALOFT. THERE IS NO  SIGNIFICANT CHANGE EXPECTED IN THE UPPER-LEVEL ENVIRONMENT, WITH LOW  VWS AND STRONG POLEWARD OUTFLOW PERSISTING THROUGH 36H. THE  PRIMARY INTENSITY FACTORS ARE THUS THE RELATIVELY MARGINAL SSTS  (27C) AND THE LARGE SIZE OF THE CORE AND THE TWO FACTORS TOGETHER  SUPPORT A STEADY OR GRADUAL DECREASE IN INTENSITY THOUGH 12H AND  THEN STEADIER WEAKENING THROUGH 36H. ONCE THE SYSTEM MAKES THE  TURN NORTHEAST BY 48H, STEADY WEAKENING IS FORECAST AS THE SYSTEM  ENCOUNTERS STEADILY COOLER SSTS, AT OR BELOW 26C, AND DRAMATICALLY  INCREASED MID-LEVEL SHEAR. IN THE LATER PORTION OF THE FORECAST, TY SURIGAE WILL CONTINUE  TO ACCELERATE EAST-NORTHEASTWARD AHEAD OF AN ADVANCING MAJOR  SHORTWAVE TROUGH AND ALONG THE NORTHERN PERIPHERY OF THE STR TO THE  SOUTHEAST. MOST AVAILABLE GUIDANCE SUGGESTS THAT TC 02W WILL NOT BE  CAPTURED BY THE PASSING SHORTWAVE, WHICH WILL MISS THE SYSTEM TO THE  NORTH, BUT WILL CONTINUE TRACKING EASTWARD AS IT WEAKENS. THE  PRIMARY IMPACT OF THE SHORTWAVE WILL BE TO IMPART A STRONG WESTERLY  FLOW ALOFT, INCREASING VWS TO ABOVE 50 KNOTS. THE SYSTEM WILL TRANSIT  GENERALLY ALONG THE 26C ISOTHERM, BUT DUE TO THE VERY HIGH SHEAR AND  THE CONVERGENT NATURE OF THE WESTERLY FLOW ALOFT, WILL STEADILY  WEAKEN THROUGH 120H. AS TY 02W MOVES EASTWARD ALONG THE  BAROCLINIC ZONE AND DEVELOPS A FRONTAL STRUCTURE, IT IS FORECAST TO  BEGIN EXTRA-TROPICAL TRANSITION (ETT) BY 96H.
02W(SURIGAE). WARNING 28 ISSUED AT 20/09UTC.TY 02W REMAINS IN A GENERALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY LOW (8-12 KTS) AND STRONG POLEWARD AND EQUATORWARD OUTFLOW. SSTS REMAIN GENERALLY WARM, THOUGH RECENT HYCOM MODEL ANALYSIS SUGGESTS SIGNIFICANT UPWELLING, PRIMARILY TO THE SOUTH IN THE STORMS WAKE. HOWEVER, NOW THAT THE SYSTEM HAS PICKED UP FORWARD SPEED ONCE MORE, IT IS MOVING AWAY FROM THE INDUCED POOL OF COOLER WATERS AND INTO A REGION OF 27-28C WATERS. TY SURIGAE IS FORECAST TO TRACK NORTHEASTWARD ALONG THE WESTERN PERIPHERY OF A DEEP SUBTROPICAL RIDGE (STR) THROUGH 36H, THEN ROUND THE RIDGE AXIS AND TURN SHARPLY NORTHEAST AHEAD OF STRONG MID-LATITUDE SHORTWAVE TROUGH MOVING IN FROM THE WEST. BY 72H, SURIGAE WILL BE ON A NEAR EASTWARD COURSE, STEADILY ACCELERATING AS IT BEGINS TO INTERACT WITH THE SUBTROPICAL JET ALOFT. THERE IS NO SIGNIFICANT CHANGE EXPECTED IN THE UPPER-LEVEL ENVIRONMENT, WITH LOW VWS AND STRONG POLEWARD OUTFLOW PERSISTING THROUGH 36H. THE PRIMARY INTENSITY FACTORS ARE THUS THE RELATIVELY MARGINAL SSTS (27C) AND THE LARGE SIZE OF THE CORE AND THE TWO FACTORS TOGETHER SUPPORT A STEADY OR GRADUAL DECREASE IN INTENSITY THOUGH 12H AND THEN STEADIER WEAKENING THROUGH 36H. ONCE THE SYSTEM MAKES THE TURN NORTHEAST BY 48H, STEADY WEAKENING IS FORECAST AS THE SYSTEM ENCOUNTERS STEADILY COOLER SSTS, AT OR BELOW 26C, AND DRAMATICALLY INCREASED MID-LEVEL SHEAR. IN THE LATER PORTION OF THE FORECAST, TY SURIGAE WILL CONTINUE TO ACCELERATE EAST-NORTHEASTWARD AHEAD OF AN ADVANCING MAJOR SHORTWAVE TROUGH AND ALONG THE NORTHERN PERIPHERY OF THE STR TO THE SOUTHEAST. MOST AVAILABLE GUIDANCE SUGGESTS THAT TC 02W WILL NOT BE CAPTURED BY THE PASSING SHORTWAVE, WHICH WILL MISS THE SYSTEM TO THE NORTH, BUT WILL CONTINUE TRACKING EASTWARD AS IT WEAKENS. THE PRIMARY IMPACT OF THE SHORTWAVE WILL BE TO IMPART A STRONG WESTERLY FLOW ALOFT, INCREASING VWS TO ABOVE 50 KNOTS. THE SYSTEM WILL TRANSIT GENERALLY ALONG THE 26C ISOTHERM, BUT DUE TO THE VERY HIGH SHEAR AND THE CONVERGENT NATURE OF THE WESTERLY FLOW ALOFT, WILL STEADILY WEAKEN THROUGH 120H. AS TY 02W MOVES EASTWARD ALONG THE BAROCLINIC ZONE AND DEVELOPS A FRONTAL STRUCTURE, IT IS FORECAST TO BEGIN EXTRA-TROPICAL TRANSITION (ETT) BY 96H.

02W(SURIGAE).NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH 72H AND THE JTWC FORECAST TRACK IS SET WITH  HIGH CONFIDENCE. THE INTENSITY FORECAST IS SET ON THE HIGH END OF  THE GUIDANCE ENVELOPE AND CLOSELY TRACKS THE HWRF SOLUTION WITH  MODERATE CONFIDENCE.NUMERICAL MODEL GUIDANCE IS IN OVERALL GOOD AGREEMENT THOUGH BEGINS TO SHOW  SIGNIFICANT SPREAD IN BOTH ALONG AND CROSS-TRACK UNCERTAINTY AFTER  96H DUE TO THE UNCERTAINTY SURROUNDING THE IMPACT OF THE  SHORTWAVE TROUGH. THE JTWC FORECAST TRACK IS SET JUST SOUTH FROM THE  PREVIOUS FORECAST AND LIES JUST NORTH OF THE MULTI-MODEL CONSENSUS  WITH MODERATE CONFIDENCE.
02W(SURIGAE).NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH 72H AND THE JTWC FORECAST TRACK IS SET WITH HIGH CONFIDENCE. THE INTENSITY FORECAST IS SET ON THE HIGH END OF THE GUIDANCE ENVELOPE AND CLOSELY TRACKS THE HWRF SOLUTION WITH MODERATE CONFIDENCE.NUMERICAL MODEL GUIDANCE IS IN OVERALL GOOD AGREEMENT THOUGH BEGINS TO SHOW SIGNIFICANT SPREAD IN BOTH ALONG AND CROSS-TRACK UNCERTAINTY AFTER 96H DUE TO THE UNCERTAINTY SURROUNDING THE IMPACT OF THE SHORTWAVE TROUGH. THE JTWC FORECAST TRACK IS SET JUST SOUTH FROM THE PREVIOUS FORECAST AND LIES JUST NORTH OF THE MULTI-MODEL CONSENSUS WITH MODERATE CONFIDENCE.

02W(SURIGAE). 20/0503UTC.AMSR2 MICROWAVE PASS CONFIRMED A VERY WELL DEFINED  AND INTENSE 55-KM EYEWALL AND THE 37GHZ IMAGE REVEALED A SMALLER AND  WEAKER INNER EYEWALL AT ABOUT 28-KM FROM THE CENTER. AMSR2  WINDSPEED MEASUREMENT IS 110 KNOTS.
02W(SURIGAE). 20/0503UTC.AMSR2 MICROWAVE PASS CONFIRMED A VERY WELL DEFINED AND INTENSE 55-KM EYEWALL AND THE 37GHZ IMAGE REVEALED A SMALLER AND WEAKER INNER EYEWALL AT ABOUT 28-KM FROM THE CENTER. AMSR2 WINDSPEED MEASUREMENT IS 110 KNOTS.


02W(SURIGAE). 20/0731UTC. DMSP VISIBLE.ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THAT  TY SURIGAE CONTINUES TO MAINTAIN A ROUGHLY 55-KM WIDE EYE, THOUGH AT  LEAST IN THE VISIBLE AND INFRARED BANDS HAS BECOME SLIGHTLY MORE  RAGGED.
02W(SURIGAE). 20/0731UTC. DMSP VISIBLE.ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THAT TY SURIGAE CONTINUES TO MAINTAIN A ROUGHLY 55-KM WIDE EYE, THOUGH AT LEAST IN THE VISIBLE AND INFRARED BANDS HAS BECOME SLIGHTLY MORE RAGGED.

02W(SURIGAE). 20/06UTC.
02W(SURIGAE). 20/06UTC.

INVEST 95S. TROPICAL CYCLONE FORMATION ALERT.ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 200256Z SSMIS 91GHZ MICROWAVE IMAGE REVEAL FORMATIVE  BANDING WITH CYCLING CONVECTION TO THE NORTHEAST AND SOUTH OF THE  LOW LEVEL CIRCULATION CENTER (LLCC). INVEST 95S IS IN AN ENVIRONMENT CONDUCIVE FOR  INTENSIFICATION, WITH MODERATE EQUATORWARD AND EASTWARD OUTFLOW  ALOFT, LOW TO MODERATE (15-20KTS) VERTICAL WIND SHEAR, AND WARM  (29-30C) SEA SURFACE TEMPERATURES.
INVEST 95S. TROPICAL CYCLONE FORMATION ALERT.ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 200256Z SSMIS 91GHZ MICROWAVE IMAGE REVEAL FORMATIVE BANDING WITH CYCLING CONVECTION TO THE NORTHEAST AND SOUTH OF THE LOW LEVEL CIRCULATION CENTER (LLCC). INVEST 95S IS IN AN ENVIRONMENT CONDUCIVE FOR INTENSIFICATION, WITH MODERATE EQUATORWARD AND EASTWARD OUTFLOW ALOFT, LOW TO MODERATE (15-20KTS) VERTICAL WIND SHEAR, AND WARM (29-30C) SEA SURFACE TEMPERATURES.

INVEST 95S. GLOBAL MODELS ARE IN GENERAL AGREEMENT THAT INVEST 95S WILL TRACK WESTWARD AS IT INTENSIFIES AND  PASSES NORTH OF MADAGASCAR OVER THE NEXT 24 HOURS.
INVEST 95S. GLOBAL MODELS ARE IN GENERAL AGREEMENT THAT INVEST 95S WILL TRACK WESTWARD AS IT INTENSIFIES AND PASSES NORTH OF MADAGASCAR OVER THE NEXT 24 HOURS.

INVEST 95S.
INVEST 95S.


INVEST 95S. 20/0623UTC.ASCAT-B BULLSEYE PASS  SHOWS A WELL DEFINED LLCC AND AN ASYMMETRIC WIND FIELD, WITH 25-30KT  WINDS AND A RELATIVELY SMALLER AREA OF 30-35KT WINDS IN THE SOUTHERN  SEMICIRCLE. THE AFOREMENTIONED DATA LEND HIGH CONFIDENCE TO THE  ANALYSIS POSITION.
INVEST 95S. 20/0623UTC.ASCAT-B BULLSEYE PASS SHOWS A WELL DEFINED LLCC AND AN ASYMMETRIC WIND FIELD, WITH 25-30KT WINDS AND A RELATIVELY SMALLER AREA OF 30-35KT WINDS IN THE SOUTHERN SEMICIRCLE. THE AFOREMENTIONED DATA LEND HIGH CONFIDENCE TO THE ANALYSIS POSITION.

20/0930UTC. THE JTWC IS ISSUING 6HOURLY WARNINGS ON 02W(SURIGAE) AND 3HOURLY SATELLITE BULLETINS. INVEST 95S IS UP-GRADED TO HIGH: WINDS ARE LIKELY TO REACH AT LEAST 35KNOTS CLOSE TO THE CENTER WITHIN 24HOURS. 3HOURLY SATELLITE BULLETINS ARE NOW ISSUED ON 95S.
20/0930UTC. THE JTWC IS ISSUING 6HOURLY WARNINGS ON 02W(SURIGAE) AND 3HOURLY SATELLITE BULLETINS. INVEST 95S IS UP-GRADED TO HIGH: WINDS ARE LIKELY TO REACH AT LEAST 35KNOTS CLOSE TO THE CENTER WITHIN 24HOURS. 3HOURLY SATELLITE BULLETINS ARE NOW ISSUED ON 95S.
Rédigé par PATRICK HOAREAU le Mardi 20 Avril 2021 à 13:46