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Western Pacific: 09W(IN-FA) has grown into a Typhoon/CAT2 and is still intensifying, 10W(CEMPAKA) made landfall as CAT1, 21/03utc updates



JTWC HAS BEEN ISSUING 6HOURLY WARNINGS ON 09W AND 10W. 3HOURLY SATELLITE BULLETINS ARE ISSUED FOR BOTH SYSTEMS.
JTWC HAS BEEN ISSUING 6HOURLY WARNINGS ON 09W AND 10W. 3HOURLY SATELLITE BULLETINS ARE ISSUED FOR BOTH SYSTEMS.
2021 JULY 21 0150UTC #WESTERNNORTHPACIFIC
TY #09W #INFA
WARNING 20/JTWC
As of 00:00 UTC July 21, 2021:
Location: 24.1°N 127.9°E
Maximum Winds: 95 kt ( 175km/h)
Gusts: 115 kt ( 215km/h)
Minimum Central Pressure: 953 mb
CATEGORY US: 2
INTENSIFYING
LOCATED AT 21/00UTC APPROXIMATELY 265 KM SOUTH OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED WESTWARD AT 05 KM/H OVER THE PAST SIX HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 210000Z IS 45 FEET.
Satellite bulletins are to be found in the comments of this post on JTWC BIS
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TS #10W #CEMPAKA
WARNING 11/JTWC
As of 00:00 UTC July 21, 2021:
Location: 21.9°N 110.9°E
Maximum Winds: 35 kt (65km/h)
Gusts: 45 kt ( 85km/h)
Minimum Central Pressure: 998 mb
OVER-LAND
LOCATED AT 21/00UTC APPROXIMATELY 340 KM WEST OF HONG KONG, HAS TRACKED WEST-NORTHWESTWARD AT 09 KM/H OVER THE PAST SIX HOURS.

Cheers,
Patrick Hoareau
 JTWC PH
ILES SOEURS

Joint Typhoon Warning Center

TY 09W(IN-FA). WARNING 20 ISSUED AT 21/03UTC.THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING.  FORECAST DISCUSSION: TY IN-FA WILL CONTINUE WESTWARD TOWARD NORTHERN TAIWAN UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE(STR). AFTER 48H, IT WILL BEGIN TO ROUND THE SOUTHWESTERN EDGE OF THE STR AND TURN NORTHWESTWARD, PASSING TO THE NORTH OF TAIWAN THEN MAKING LANDFALL NEAR WENZHOU JUST BEFORE 96H. THE FAVORABLE ENVIRONMENT WILL FUEL FURTHER INTENSIFICATION TO A PEAK OF 105KNOTS/CAT 3 BY 36H. AFTERWARD, INCREASING VERTICAL WIND SHEAR, DRY AIR ENTRAINMENT, THEN LANDFALL INTO CHINA WILL GRADUALLY THEN RAPIDLY ERODE THE SYSTEM DOWN TO 85KNOTS/CAT 2 AT 72H AS IT PASSES TO THE NORTH OF TAIWAN, 55KNOTS AT LANDFALL, THEN DOWN TO 30KNOTS BY 120H.
TY 09W(IN-FA). WARNING 20 ISSUED AT 21/03UTC.THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TY IN-FA WILL CONTINUE WESTWARD TOWARD NORTHERN TAIWAN UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE(STR). AFTER 48H, IT WILL BEGIN TO ROUND THE SOUTHWESTERN EDGE OF THE STR AND TURN NORTHWESTWARD, PASSING TO THE NORTH OF TAIWAN THEN MAKING LANDFALL NEAR WENZHOU JUST BEFORE 96H. THE FAVORABLE ENVIRONMENT WILL FUEL FURTHER INTENSIFICATION TO A PEAK OF 105KNOTS/CAT 3 BY 36H. AFTERWARD, INCREASING VERTICAL WIND SHEAR, DRY AIR ENTRAINMENT, THEN LANDFALL INTO CHINA WILL GRADUALLY THEN RAPIDLY ERODE THE SYSTEM DOWN TO 85KNOTS/CAT 2 AT 72H AS IT PASSES TO THE NORTH OF TAIWAN, 55KNOTS AT LANDFALL, THEN DOWN TO 30KNOTS BY 120H.

Western Pacific: 09W(IN-FA) has grown into a Typhoon/CAT2 and is still intensifying, 10W(CEMPAKA) made landfall as CAT1, 21/03utc updates

09W(IN-FA).SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM CONTINUED TO INTENSIFY AS THE CENTRAL CONVECTION DEEPENED AND FEEDER BANDS HAVE BECOME MORE COMPACT AND WRAPPED TIGHTER INTO A DEFINED 45-KM EYE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE IN THE MSI LOOP. THE INITIAL INTENSITY OF 95 KNOTS/CAT 2 IS ASSESSED WITH HIGH CONFIDENCE BASED ON OVERALL ASSESSMENT OF AGENCY DVORAK ESTIMATES AND THE ADT AND REFLECTS THE SIGNIFICANT 6-HR INTENSIFICATION.
09W(IN-FA).SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM CONTINUED TO INTENSIFY AS THE CENTRAL CONVECTION DEEPENED AND FEEDER BANDS HAVE BECOME MORE COMPACT AND WRAPPED TIGHTER INTO A DEFINED 45-KM EYE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EYE FEATURE IN THE MSI LOOP. THE INITIAL INTENSITY OF 95 KNOTS/CAT 2 IS ASSESSED WITH HIGH CONFIDENCE BASED ON OVERALL ASSESSMENT OF AGENCY DVORAK ESTIMATES AND THE ADT AND REFLECTS THE SIGNIFICANT 6-HR INTENSIFICATION.

09W(IN-FA). MODEL DISCUSSION: NUMERICAL MODELS ARE TIGHT UP TO 72H WITH EVEN AND GRADUAL SPREAD TO 240KM. AFTERWARD, THE MODELS DIVERGE FURTHER TO OVER 590KM BY 120H WITH UKMET ON THE LEFT AND ECMF ON THE RIGHT MARGINS OF THE ENVELOPE. NOTABLY, NVGM DEFLECTS THE VORTEX ABRUPTLY EASTWARD AFTER 72H.
09W(IN-FA). MODEL DISCUSSION: NUMERICAL MODELS ARE TIGHT UP TO 72H WITH EVEN AND GRADUAL SPREAD TO 240KM. AFTERWARD, THE MODELS DIVERGE FURTHER TO OVER 590KM BY 120H WITH UKMET ON THE LEFT AND ECMF ON THE RIGHT MARGINS OF THE ENVELOPE. NOTABLY, NVGM DEFLECTS THE VORTEX ABRUPTLY EASTWARD AFTER 72H.

TS 10W(CEMPAKA). WARNING 11 ISSUED AT 20/03UTC.THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING.  FORECAST DISCUSSION: TS 10W WILL TRACK FURTHER INLAND AND GENERALLY WESTWARD UNDER A LOW REFLECTION OF THE STR. AFTER 36H, AS SECONDARY STR TO THE WEST WILL ASSUME STEERING AND DRIVE THE CYCLONE SOUTHWARD INTO THE GULF OF TONKIN (GOT) AND INTO HAINAN BY 72H. AFTERWARD, THE SYSTEM WILL DRIFT EAST-NORTHEASTWARD WITH AN AMPLIFIED MONSOON FLOW IN THE SOUTH CHINA SEA. THE RUGGED TERRAIN AND INCREASED VERTICAL WIND SHEAR WILL CONTINUE TO ERODE THE SYSTEM DOWN TO 25KNOTS BY 24H. HOWEVER, AFTER IT EXITS BACK ONTO WATER IN THE GOT, IT WILL REGAIN TS INTENSITY MOMENTARILY UNTIL IT BECOMES EXPOSED TO HIGH VERTICAL WIND SHEAR IN THE SOUTH CHINA SEA ASSOCIATED WITH THE SOUTHWEST MONSOON. THERE IS A DISTINCT POSSIBILITY THAT TS CEMPAKA WILL DISSIPATE OVER LAND IN THE NEXT 36HRS.
TS 10W(CEMPAKA). WARNING 11 ISSUED AT 20/03UTC.THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 10W WILL TRACK FURTHER INLAND AND GENERALLY WESTWARD UNDER A LOW REFLECTION OF THE STR. AFTER 36H, AS SECONDARY STR TO THE WEST WILL ASSUME STEERING AND DRIVE THE CYCLONE SOUTHWARD INTO THE GULF OF TONKIN (GOT) AND INTO HAINAN BY 72H. AFTERWARD, THE SYSTEM WILL DRIFT EAST-NORTHEASTWARD WITH AN AMPLIFIED MONSOON FLOW IN THE SOUTH CHINA SEA. THE RUGGED TERRAIN AND INCREASED VERTICAL WIND SHEAR WILL CONTINUE TO ERODE THE SYSTEM DOWN TO 25KNOTS BY 24H. HOWEVER, AFTER IT EXITS BACK ONTO WATER IN THE GOT, IT WILL REGAIN TS INTENSITY MOMENTARILY UNTIL IT BECOMES EXPOSED TO HIGH VERTICAL WIND SHEAR IN THE SOUTH CHINA SEA ASSOCIATED WITH THE SOUTHWEST MONSOON. THERE IS A DISTINCT POSSIBILITY THAT TS CEMPAKA WILL DISSIPATE OVER LAND IN THE NEXT 36HRS.
10W MADE LANDFALL NEAR YANGJIAN, CHINA, SHORTLY AFTER 20/09UTC NEAR PEAK INTENSITY OF 80KNOTS/CAT 1.
1021071706 190N1156E  15
1021071712 193N1155E  15
1021071718 196N1153E  15
1021071800 200N1151E  20
1021071806 204N1144E  25
1021071812 206N1137E  30
1021071818 207N1133E  40
1021071900 209N1131E  45
1021071906 210N1129E  50
1021071912 211N1127E  55
1021071918 212N1125E  65
1021072000 213N1124E  65
1021072006 215N1122E  80
1021072012 217N1119E  75
1021072018 217N1114E  55
1021072100 219N1109E  35

Western Pacific: 09W(IN-FA) has grown into a Typhoon/CAT2 and is still intensifying, 10W(CEMPAKA) made landfall as CAT1, 21/03utc updates

10W(CEMPAKA).SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM CONTINUED TO TRACK DEEPER INLAND CHINA AS IT RAPIDLY DECAYED, AS EVIDENCED BY COLLAPSING CONVECTIVE CLOUD TOPS. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A BROAD LOW LEVEL CIRCULATION FEATURE IN A CMA COMPOSITE RADAR LOOP AND TRIANGULATED FROM NEARBY SURFACE WIND OBSERVATIONS. THE INITIAL INTENSITY OF 35 KNOTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON NEARBY SURFACE OBSERVATIONS INCLUDING ONE FROM YANGCHUN CITY 30KM TO THE NE (SE15G20KTS, 1000MB) AND SUPPORTED BY A DVORAK ESTIMATE FROM RCTP.
10W(CEMPAKA).SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM CONTINUED TO TRACK DEEPER INLAND CHINA AS IT RAPIDLY DECAYED, AS EVIDENCED BY COLLAPSING CONVECTIVE CLOUD TOPS. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A BROAD LOW LEVEL CIRCULATION FEATURE IN A CMA COMPOSITE RADAR LOOP AND TRIANGULATED FROM NEARBY SURFACE WIND OBSERVATIONS. THE INITIAL INTENSITY OF 35 KNOTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON NEARBY SURFACE OBSERVATIONS INCLUDING ONE FROM YANGCHUN CITY 30KM TO THE NE (SE15G20KTS, 1000MB) AND SUPPORTED BY A DVORAK ESTIMATE FROM RCTP.

10W(CEMPAKA). MODEL DISCUSSION: NUMERICAL MODELS HAVE BECOME MORE SPREAD OUT WITH UKMET, ECMF, AND JGSM KEEPING THE VORTEX OVER LAND, AND THE REMAINDER MAINTAINING AN ANTI-CLOCKWISE LOOPING MOTION. IN VIEW OF THESE, PLUS THE POSSIBILITY OF EARLY DISSIPATION OVER LAND, THERE IS LOW CONFIDENCE IN THE JTWC TRACK AND INTENSITY FORECAST.
10W(CEMPAKA). MODEL DISCUSSION: NUMERICAL MODELS HAVE BECOME MORE SPREAD OUT WITH UKMET, ECMF, AND JGSM KEEPING THE VORTEX OVER LAND, AND THE REMAINDER MAINTAINING AN ANTI-CLOCKWISE LOOPING MOTION. IN VIEW OF THESE, PLUS THE POSSIBILITY OF EARLY DISSIPATION OVER LAND, THERE IS LOW CONFIDENCE IN THE JTWC TRACK AND INTENSITY FORECAST.

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Rédigé par PATRICK HOAREAU le Wednesday, July 21st 2021 à 07:35