ABIO10 PGTW 281800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN
/OCEAN/281800Z-291800ZOCT2021//
RMKS/
1. NORTH INDIAN OCEAN AREA (MALAY PENINSULA WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
2. SOUTH INDIAN OCEAN AREA (135E WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION (INVEST 93S) HAS PERSISTED NEAR 6.6S
86.6E, APPROXIMATELY 842 NM EAST OF DIEGO GARCIA. ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS FLARING CONVECTION OBSCURING AN ELONGATED,
DISORGANIZED LOW LEVEL CIRCULATION (LLC). A 281626Z PARTIAL ASCAT-B
PASS SHOWS A 30-35 KNOT WIND FIELD APPROXIMATELY 70-80 NM TO THE
NORTH-NORTHWEST OF THE LLC WITH 20-25 KNOT WINDS ELSEWHERE. THE
AFOREMENTIONED WIND FIELD IS IN ASSOCIATION WITH A WEAK MJO EVENT
TAKING PLACE OVER THE EASTERN INDIAN OCEAN WHICH COULD CONTRIBUTE TO
ENHANCEMENT OF THIS DISTURBANCE. ENVIRONMENTAL ANALYSIS INDICATES
MARGINAL CONDITIONS FOR DEVELOPMENT WITH STRONG EQUATORWARD OUTFLOW
AND WARM (28-29C) SEA SURFACE TEMPERATURES OFFSET BY STRONG (25+ KT)
VERTICAL WINDSHEAR. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 93S
WILL TRACK WEST-SOUTHWESTWARD OVER THE NEXT 48 HOURS. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1003 MB. THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS UPGRADED TO LOW.
(2) NO OTHER SUSPECT AREAS.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.//
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(1) THE AREA OF CONVECTION (INVEST 93S) PREVIOUSLY LOCATED
NEAR 6.6S 86.6E IS NOW LOCATED NEAR 7.8S 87.1E, APPROXIMATELY 870 NM
EAST OF DIEGO GARCIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS FLARING CONVECTION PARTIALLY OBSCURING A LOW LEVEL
CIRCULATION (LLC) THAT HAS BECOME MORE WELL DEFINED. A 290028Z SSMIS
91GHZ IMAGE SHOWS DEEP CONVECTION IN THE WESTERN SEMICIRCLE AS WELL
AS FORMATIVE BANDING WRAPPING INTO THE LLC. ENVIRONMENTAL ANALYSIS
INDICATES MARGINAL CONDITIONS FOR DEVELOPMENT WITH STRONG OUTFLOW
AND WARM (28-29C) SEA SURFACE TEMPERATURES OFFSET BY STRONG (30+ KT)
VERTICAL WINDSHEAR. GLOBAL MODELS CONTINUE TO AGREE THAT 93S WILL
TRACK WEST-SOUTHWESTWARD OVER THE NEXT 48 HOURS. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 30 TO 35 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1002 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS UPGRADED TO MEDIUM.
ABIO10 PGTW 291800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN
OCEAN/291800Z-301800ZOCT2021//
RMKS/
1. NORTH INDIAN OCEAN AREA (MALAY PENINSULA WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
2. SOUTH INDIAN OCEAN AREA (135E WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (INVEST 93S) PREVIOUSLY LOCATED
NEAR 6.6S 86.6E IS NOW LOCATED NEAR 9.6S 86.9E, APPROXIMATELY 866 NM
EAST OF DIEGO GARCIA. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY AND A 291307Z SSMIS 91GHZ IMAGE REVEAL AN AREA OF DEEP
CONVECTION LOCATED SOUTHWEST OF AN ASSESSED LOW LEVEL CIRCULATION
(LLC). A PARTIAL 291604Z ASCAT METOP-B PASS SHOWS THE EAST SIDE OF
THE AFOREMENTIONED LLC WITH 20-25 KT WINDS LOCATED IN THE SOUTHERN
SEMICIRCLE. ENVIRONMENTAL ANALYSIS INDICATES INVEST 93S IS IN A
MARGINALLY FAVORABLE ENVIRONMENT WITH GOOD WESTWARD AND POLEWARD
OUTFLOW SUPPORTED BY ANTICYCLONIC TURNING ALOFT AND WARM (28-29C)
SEA SURFACE TEMPERATURES, OFFSET BY MODERATE (15-20KT) VERTICAL WIND
SHEAR. GLOBAL MODELS ARE IN AGREEMENT THAT INVEST 93S WILL TRACK
WESTWARD AND CONSOLIDATE OVER THE NEXT 24 HOURS. 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 MEDIUM.
(2) NO OTHER SUSPECT AREAS.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.//
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WTXS21 PGTW 292100 COR
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 93S) CORRECTED//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 9.8S 86.7E TO 12.8S 80.9E
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 20 TO 25 KNOTS. METSAT
IMAGERY AT 291810Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 10.0S 86.6E. THE SYSTEM IS MOVING SOUTH-SOUTHWESTWARD AT 11
KNOTS.
2. REMARKS:
THE AREA OF CONVECTION (INVEST 93S) PREVIOUSLY LOCATED NEAR 9.6S
86.9E IS NOW LOCATED NEAR 10.0S 86.6E, APPROXIMATELY 851 NM EAST OF
DIEGO GARCIA. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY AND
A 291307Z SSMIS 91GHZ IMAGE REVEALS AN AREA OF DEEP CONVECTION
LOCATED SOUTHWEST OF AN ASSESSED LOW LEVEL CIRCULATION (LLC). A
PARTIAL 291604Z ASCAT METOP-B PASS SHOWS THE EAST SIDE OF THE
AFOREMENTIONED LLC WITH 20-25 KT WINDS LOCATED IN THE SOUTHERN
SEMICIRCLE. ENVIRONMENTAL ANALYSIS INDICATES INVEST 93S IS IN A
MARGINALLY FAVORABLE ENVIRONMENT WITH GOOD WESTWARD AND POLEWARD
OUTFLOW SUPPORTED BY ANTICYCLONIC TURNING ALOFT AND WARM (28-29C)
SEA SURFACE TEMPERATURES, OFFSET BY MODERATE (15-20KT) VERTICAL WIND
SHEAR. GLOBAL MODELS ARE IN AGREEMENT THAT INVEST 93S WILL TRACK
WESTWARD AND CONSOLIDATE OVER THE NEXT 24 HOURS. 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 IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
302100Z.
4. JUSTIFICATION FOR CORRECTION: CORRECTED PREVIOUS POSITION IN
PARA. 2.//
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ABIO10 PGTW 310930
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN
/REISSUED/310930Z-311800ZOCT2021//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/302051ZOCT2021
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. NORTH INDIAN OCEAN AREA (MALAY PENINSULA WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY: NONE.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
2. SOUTH INDIAN OCEAN AREA (135E WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (INVEST 93S) PREVIOUSLY LOCATED
NEAR 12.1S 82.6E IS NOW LOCATED NEAR 13.1S 80.2E, APPROXIMATELY 576
NM SOUTHEAST OF DIEGO GARCIA. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY AND A 310802Z AMSR2 89GHZ IMAGE REVEAL A BROAD LOW
LEVEL CIRCULATION CENTER (LLCC) DEFINED BY WELL-DEFINED, BUT SHALLOW
BANDING WITH VERY WEAK CONVECTION SHEARED TO THE SOUTHWEST.
ENVIRONMENTAL ANALYSIS INDICATES AN UNFAVORABLE ENVIRONMENT FOR
DEVELOPMENT WITH HIGH (25-30 KNOTS) NORTHEAST VERTICAL WIND SHEAR
AND MARGINAL SEA SURFACE TEMPERATURES (26C) OFFSET BY GOOD POLEWARD
OUTFLOW. ADDITIONALLY, THERE IS SIGNIFICANT DRY AIR ENTRAINMENT
THROUGHOUT THE MID-LEVELS THAT IS HINDERING CONVECTIVE DEVELOPMENT.
GLOBAL MODELS ARE IN GOOD AGREEMENT THAT THE CIRCULATION ASSOCIATED
WITH INVEST 93S WILL CONTINUE TO TRACK WESTWARD, BUT IT IS NOT
EXPECTED TO DEVELOP AT THIS TIME. 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 IS DOWNGRADED
TO LOW. THIS CANCELS REF A.
(2) NO OTHER SUSPECT AREAS.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: CANCELLED TCFA FOR AREA IN PARA 2.B.(1)
(INVEST 93S).//
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