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Western Pacific: the cyclonic pair 09W & 11W still monitored, Eastern Pacific/Atlantic: Tropical Cyclone Formation Alerts re-issued, 26/03utc updates



JTWC HAS BEEN ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON 09W AND 11W.
JTWC HAS BEEN ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON 09W AND 11W.
2021 JULY 26 0320UTC #WESTERNNORTHPACIFIC
TS #09W #INFA
WARNING 40/JTWC
As of 00:00 UTC July 26, 2021:
Location: 30.6°N 121.1°E
Maximum Winds: 40 kt ( 75km/h)
Gusts: 50 kt ( 95km/h)
Minimum Central Pressure: 988 mb
WEAKENING WHILE PUSHING IN-LAND.
LOCATED AT 26/00UTC APPROXIMATELY 75 KM SOUTH-SOUTHWEST OF SHANGHAI, CHINA, HAS TRACKED WEST-NORTHWESTWARD
AT 07 KM/H OVER THE PAST SIX HOURS.

Satellite bulletins are to be found in the comments of this post on JTWC BIS
-----------------------------------------------
STS #11W #NEPARTAK
WARNING 11/JTWC
As of 00:00 UTC July 26, 2021:
Location: 33.5°N 149.8°E
Maximum Winds: 35 kt ( 65km/h)
Gusts: 45 kt ( 85km/)
Minimum Central Pressure: 996 mb
SUBTROPICAL
LOCATED AT 26/00UTC APPROXIMATELY 945 KM EAST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHWESTWARD AT 13 KM/H OVER
THE PAST SIX HOURS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 260000Z IS 13 FEET.

Satellite bulletins are to be found in the comments of this post on JTWC BIS

Cheers,
Patrick Hoareau
 JTWC PH
ILES SOEURS

Joint Typhoon Warning Center

TS 09W(IN-FA). WARNING 40 ISSUED AT 26/03UTC.THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING.  FORECAST DISCUSSION: TS 09W WILL CONTINUE WEST-NORTHWESTWARD INTO THE CHINESE INTERIOR THEN RECURVE NORTHEASTWARD AFTER 48H AS IT ROUNDS THE WESTERN EDGE OF THE SUBTROPICAL RIDGE. LAND INTERACTION WILL MOSTLY BE RESPONSIBLE FOR ITS GRADUAL DECAY DOWN TO 25KNOTS BY 120H AS IT REACHES THE TIP OF SHANDONG PENINSULA AND POISED TO MAKE AN EXIT INTO THE GULF OF POHAI. THERE IS, HOWEVER, A POSSIBILITY THAT THE SYSTEM WILL DISSIPATE OVER LAND.
TS 09W(IN-FA). WARNING 40 ISSUED AT 26/03UTC.THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 09W WILL CONTINUE WEST-NORTHWESTWARD INTO THE CHINESE INTERIOR THEN RECURVE NORTHEASTWARD AFTER 48H AS IT ROUNDS THE WESTERN EDGE OF THE SUBTROPICAL RIDGE. LAND INTERACTION WILL MOSTLY BE RESPONSIBLE FOR ITS GRADUAL DECAY DOWN TO 25KNOTS BY 120H AS IT REACHES THE TIP OF SHANDONG PENINSULA AND POISED TO MAKE AN EXIT INTO THE GULF OF POHAI. THERE IS, HOWEVER, A POSSIBILITY THAT THE SYSTEM WILL DISSIPATE OVER LAND.

Western Pacific: the cyclonic pair 09W & 11W still monitored, Eastern Pacific/Atlantic: Tropical Cyclone Formation Alerts re-issued, 26/03utc updates

09W(IN-FA).SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM CONTINUED TO ERODE AS IT MADE LANDFALL JUST SOUTH OF SHANGHAI. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A DEFINED LOW LEVEL CIRCULATION FEATURE IN A CMA COMPOSITE RADAR LOOP. THE INITIAL INTENSITY OF 40KNOTS IS BASED ON EXTRAPOLATION FROM RECENT AGENCY DVORAK AND AUTOMATED FIXES AND EXTRAPOLATED FROM NEARBY WIND AND PRESSURE OBSERVATIONS AND CONSISTENT WITH THE DEGRADED METSAT SIGNATURE.
09W(IN-FA).SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM CONTINUED TO ERODE AS IT MADE LANDFALL JUST SOUTH OF SHANGHAI. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A DEFINED LOW LEVEL CIRCULATION FEATURE IN A CMA COMPOSITE RADAR LOOP. THE INITIAL INTENSITY OF 40KNOTS IS BASED ON EXTRAPOLATION FROM RECENT AGENCY DVORAK AND AUTOMATED FIXES AND EXTRAPOLATED FROM NEARBY WIND AND PRESSURE OBSERVATIONS AND CONSISTENT WITH THE DEGRADED METSAT SIGNATURE.

09W(IN-FA).MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIRLY GOOD AGREEMENT UP 72H. AFTERWARD, THE MODELS WIDELY SPREAD ALONG AND ACROSS-TRACK, LENDING MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST UP TO 72H THEN LOW CONFIDENCE AFTERWARD. THERE IS LOW CONFIDENCE IN THE INTENSITY FORECASTS DUE TO THE UNCERTAINTY IN THE TOPOGRAPHICAL EFFECTS.
09W(IN-FA).MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIRLY GOOD AGREEMENT UP 72H. AFTERWARD, THE MODELS WIDELY SPREAD ALONG AND ACROSS-TRACK, LENDING MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST UP TO 72H THEN LOW CONFIDENCE AFTERWARD. THERE IS LOW CONFIDENCE IN THE INTENSITY FORECASTS DUE TO THE UNCERTAINTY IN THE TOPOGRAPHICAL EFFECTS.

STS 11W(NEPARTAK). WARNING 11 ISSUED AT 26/03UTC. THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING.  FORECAST DISCUSSION: SUBTROPICAL CYCLONE 11W WILL CONTINUE TO TRACK NORTHWESTWARD UNDER THE STEERING SUBTROPICAL RIDGE ON A PINWHEEL PATTERN AROUND AN UPPER LEVEL LOW TO THE SOUTHWEST, MAKING LANDFALL OVER NORTHERN HONSHU NEAR KESENNUMA, JAPAN, NEAR 48H. THE MARGINAL ENVIRONMENT - STRONG VERTICAL WIND SHEAR OFFSET BY STRONG POLEWARD OUTFLOW AND WARM SST - WILL FUEL A SLIGHT INTENSIFICATION TO 40KNOTS AT 24-36H. AFTERWARD, THE UPPER LEVEL LOW WILL COME INTO CLOSE PROXIMITY OF 11W AND PROMOTE SUBSIDENCE ALOFT AND INDUCE THE INFLOW OF COLD DRY AIR IN THE LOWER LEVELS. THESE PLUS THE TOPOGRAPHICAL EFFECTS AFTER LANDFALL WILL GRADUALLY ERODE THE SYSTEM DOWN TO 25KNOTS BY THE TIME  IT EXITS INTO THE SEA OF JAPAN (SOJ) BEFORE 96H. THE COOLER SSTS IN THE SOJ FOLLOWED BY A SECONDARY LANDFALL INTO HOKKAIDO AFTER THE SYSTEM RECURVES NORTHEASTWARD AROUND THE STR AXIS WILL FURTHER ERODE 11W TO DISSIPATION BY 96H.
STS 11W(NEPARTAK). WARNING 11 ISSUED AT 26/03UTC. THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: SUBTROPICAL CYCLONE 11W WILL CONTINUE TO TRACK NORTHWESTWARD UNDER THE STEERING SUBTROPICAL RIDGE ON A PINWHEEL PATTERN AROUND AN UPPER LEVEL LOW TO THE SOUTHWEST, MAKING LANDFALL OVER NORTHERN HONSHU NEAR KESENNUMA, JAPAN, NEAR 48H. THE MARGINAL ENVIRONMENT - STRONG VERTICAL WIND SHEAR OFFSET BY STRONG POLEWARD OUTFLOW AND WARM SST - WILL FUEL A SLIGHT INTENSIFICATION TO 40KNOTS AT 24-36H. AFTERWARD, THE UPPER LEVEL LOW WILL COME INTO CLOSE PROXIMITY OF 11W AND PROMOTE SUBSIDENCE ALOFT AND INDUCE THE INFLOW OF COLD DRY AIR IN THE LOWER LEVELS. THESE PLUS THE TOPOGRAPHICAL EFFECTS AFTER LANDFALL WILL GRADUALLY ERODE THE SYSTEM DOWN TO 25KNOTS BY THE TIME IT EXITS INTO THE SEA OF JAPAN (SOJ) BEFORE 96H. THE COOLER SSTS IN THE SOJ FOLLOWED BY A SECONDARY LANDFALL INTO HOKKAIDO AFTER THE SYSTEM RECURVES NORTHEASTWARD AROUND THE STR AXIS WILL FURTHER ERODE 11W TO DISSIPATION BY 96H.

Western Pacific: the cyclonic pair 09W & 11W still monitored, Eastern Pacific/Atlantic: Tropical Cyclone Formation Alerts re-issued, 26/03utc updates

11W(NEPARTAK).SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A SUBTROPICAL SYSTEM WITH A BROAD, LONG SWATH OF CONVECTION CURLING INTO AN ELONGATED, NARROW, AND PARTLY EXPOSED LOW LEVEL CIRCULATION (LLC). THE MULTIPLE VORTICES OBSERVED PRIOR TO THIS WARNING CYCLE HAVE COALESCED INTO THIS LLC, WHICH WAS THE CENTROID THAT WAS BEING TRACKED BY JTWC. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE ON THIS LLC WHICH WAS PARTIALLY CAPTURED BY A 252320Z ASCAT PASS. THE INITIAL INTENSITY OF 35KNOTS IS BASED ON PATCHES OF 35-KT WIND BARBS DEPICTED IN THE ASCAT PASS OVER 220KM NORTHEASTWARD FROM THE LLC UNDER THE SWATH OF CONVECTION. ALTHOUGH NOT REPRESENTATIVE OF THE STORM POSITION, THE INITIAL INTENSITY IS SUPPORTED BY THE PGTW DVORAK AND THE ADT AUTOMATED FIXES.
11W(NEPARTAK).SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A SUBTROPICAL SYSTEM WITH A BROAD, LONG SWATH OF CONVECTION CURLING INTO AN ELONGATED, NARROW, AND PARTLY EXPOSED LOW LEVEL CIRCULATION (LLC). THE MULTIPLE VORTICES OBSERVED PRIOR TO THIS WARNING CYCLE HAVE COALESCED INTO THIS LLC, WHICH WAS THE CENTROID THAT WAS BEING TRACKED BY JTWC. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE ON THIS LLC WHICH WAS PARTIALLY CAPTURED BY A 252320Z ASCAT PASS. THE INITIAL INTENSITY OF 35KNOTS IS BASED ON PATCHES OF 35-KT WIND BARBS DEPICTED IN THE ASCAT PASS OVER 220KM NORTHEASTWARD FROM THE LLC UNDER THE SWATH OF CONVECTION. ALTHOUGH NOT REPRESENTATIVE OF THE STORM POSITION, THE INITIAL INTENSITY IS SUPPORTED BY THE PGTW DVORAK AND THE ADT AUTOMATED FIXES.


11W(NEPARTAK).MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT BUT GIVEN THE BROAD COMPLEXITY OF A SUBTROPICAL CYCLONE AND THE UNCERTAINTY OF A LAND PASSAGE, THERE IS MEDIUM CONFIDENCE IN THE JTWC TRACK AND INTENSITY FORECASTS UP TO 72H, THEN LOW CONFIDENCE AFTERWARD.
11W(NEPARTAK).MODEL DISCUSSION: NUMERICAL MODELS ARE IN OVERALL GOOD AGREEMENT BUT GIVEN THE BROAD COMPLEXITY OF A SUBTROPICAL CYCLONE AND THE UNCERTAINTY OF A LAND PASSAGE, THERE IS MEDIUM CONFIDENCE IN THE JTWC TRACK AND INTENSITY FORECASTS UP TO 72H, THEN LOW CONFIDENCE AFTERWARD.

EASTERN PACIFIC. INVEST 98E. TROPICAL CYCLONE FORMATION ALERT RE-ISSUED AT 26/01UTC.N AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 13.1N  130.3W IS NOW LOCATED NEAR 13.2N 136.5W, APPROXIMATELY 2430 KM EAST- SOUTHEAST OF HONOLULU, HAWAII. ANIMATED MULTISPECTRAL SATELLITE  IMAGERY AND A 252203Z ATM 88 GHZ MICROWAVE PASS DEPICT AN IRREGULAR  LOW LEVEL CIRCULATION (LLC) WITH DEEPENING CONVECTION TO THE NORTH  AND ALONG A FRAGMENTED SOUTHERN BAND. A 251822Z ASCAT-B IMAGE SHOWS  AN ELONGATED CIRCULATION WITH 25 KNOT WIND BARBS IN THE NORTHERN  SEMI-CIRCLE, LIKELY ASSOCIATED WITH THUNDERSTORM ACTIVITY, AND LOWER  WIND BARBS ELSEWHERE. ENVIRONMENTAL ANALYSIS INDICATES INVEST 98E IS  LOCATED IN AN AREA FAVORABLE FOR DEVELOPMENT WITH GOOD POLEWARD  OUTFLOW ALOFT, WEAK VERTICAL WIND SHEAR (10-15KTS) AND WARM SEA  SURFACE TEMPERATURES (28-29C). MAXIMUM SUSTAINED SURFACE WINDS ARE  ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED  TO BE NEAR 1004 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A  SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH.
EASTERN PACIFIC. INVEST 98E. TROPICAL CYCLONE FORMATION ALERT RE-ISSUED AT 26/01UTC.N AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 13.1N 130.3W IS NOW LOCATED NEAR 13.2N 136.5W, APPROXIMATELY 2430 KM EAST- SOUTHEAST OF HONOLULU, HAWAII. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 252203Z ATM 88 GHZ MICROWAVE PASS DEPICT AN IRREGULAR LOW LEVEL CIRCULATION (LLC) WITH DEEPENING CONVECTION TO THE NORTH AND ALONG A FRAGMENTED SOUTHERN BAND. A 251822Z ASCAT-B IMAGE SHOWS AN ELONGATED CIRCULATION WITH 25 KNOT WIND BARBS IN THE NORTHERN SEMI-CIRCLE, LIKELY ASSOCIATED WITH THUNDERSTORM ACTIVITY, AND LOWER WIND BARBS ELSEWHERE. ENVIRONMENTAL ANALYSIS INDICATES INVEST 98E IS LOCATED IN AN AREA FAVORABLE FOR DEVELOPMENT WITH GOOD POLEWARD OUTFLOW ALOFT, WEAK VERTICAL WIND SHEAR (10-15KTS) AND WARM SEA SURFACE TEMPERATURES (28-29C). MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS HIGH.
9821072200  96N1187W  20
9821072206  99N1193W  20
9821072212 104N1200W  20
9821072218 109N1207W  20
9821072300 113N1220W  20
9821072306 117N1231W  20
9821072312 119N1240W  25
9821072318 120N1251W  25
9821072400 123N1263W  25
9821072406 127N1276W  25
9821072412 128N1292W  25
9821072418 128N1307W  25
9821072500 128N1321W  25
9821072506 128N1334W  25
9821072512 130N1349W  25
9821072518 132N1365W  25
9821072600 131N1377W  30

INVEST 98E. GUIDANCE.
INVEST 98E. GUIDANCE.

ATLANTIC. INVEST 90L. TROPICAL CYCLONE FORMATION ALERT RE-ISSUED AT 25/15UTC.
ATLANTIC. INVEST 90L. TROPICAL CYCLONE FORMATION ALERT RE-ISSUED AT 25/15UTC.
9021072212 324N 830W  15
9021072218 321N 820W  15
9021072300 319N 811W  20
9021072306 315N 802W  20
9021072312 313N 793W  20
9021072318 308N 789W  25
9021072400 296N 787W  25
9021072406 293N 785W  25
9021072412 292N 774W  25
9021072418 290N 775W  30
9021072500 289N 778W  30
9021072506 290N 781W  30
9021072512 293N 784W  30
9021072518 293N 788W  30
9021072600 297N 797W  30

INVEST 90L. GUIDANCE.
INVEST 90L. GUIDANCE.

26/03UTC.
26/03UTC.

26/00UTC.
26/00UTC.

26/00UTC.
26/00UTC.


Rédigé par PATRICK HOAREAU le Monday, July 26th 2021 à 08:06