ABIO10 PGTW 190400
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE INDIAN OCEAN
/REISSUED/190400Z-191800ZNOV2021//
RMKS/
1. NORTH INDIAN OCEAN AREA (MALAY PENINSULA WEST TO COAST OF AFRICA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION (INVEST 93A) PREVIOUSLY LOCATED
NEAR 16.0N 70.1E IS NOW LOCATED NEAR 15.9N 68.7E, APPROXIMATELY 301
NM SOUTHWEST OF MUMBAI, INDIA. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY (EIR) AND A 181350Z SSMIS 91GHZ MICROWAVE IMAGE DEPICT
FRAGMENTED BANDING WRAPPING INTO A POORLY ORGANIZED LLC WITH MOST OF
THE CONVECTION SHEARED TO THE NORTHWESTERN PERIPHERY. UPPER LEVEL
ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH LOW TO
MODERATE (10 TO 20 KTS) VWS, MODERATE POLEWARD OUTFLOW AND WARM (28-
29C) SEA SURFACE TEMPERATURES. ADDITIONALLY, DRY AIR ENTRAINMENT IN
THE MID-TO-UPPER LEVELS IS HINDERING DEVELOPMENT. GLOBAL MODELS ARE
IN AGREEMENT THAT INVEST 93A WILL SEE MINIMAL DEVELOPMENT AS IT
TRACKS WEST-NORTHWESTWARD. 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
LOW.
(2) THE AREA OF CONVECTION (INVEST 92B) PREVIOUSLY LOCATED
NEAR 10.6N 83.5E HAS DISSIPATED AND IS NO LONGER SUSPECT FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE IN THE NEXT 24 HOURS.
(3) NO OTHER SUSPECT AREAS.
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: NONE.
C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: DISSIPATED AREA IN PARA 1.B.(2).//
NNNN
WTIO21 PGTW 181800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT CANCELLATION//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/172021ZNOV21//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. REMARKS: THE AREA OF CONVECTION (INVEST 92B) PREVIOUSLY LOCATED
NEAR 10.6N 83.5E IS NOW LOCATED NEAR 12.3N 80.4E, APPROXIMATELY 45
NM SOUTH OF CHENNAI, INDIA. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY AND A 181056Z SSMIS 91GHZ MICROWAVE IMAGE DEPICT A FULLY-
EXPOSED LOW-LEVEL CIRCULATION (LLC) WITH DEEP CONVECTION SHEARED
WEST OF THE LLC DUE TO PERSISTENT MODERATE TO STRONG (20-25 KNOTS)
EASTERLY VERTICAL WIND SHEAR. SURFACE OBSERVATIONS FROM CHENNAI
INDICATE EAST-NORTHEASTERLY SUSTAINED WINDS AT 10-15 KNOTS WITH SLP
NEAR 1003MB. INVEST 92B IS MAKING LANDFALL AND GLOBAL MODELS
INDICATE THE SYSTEM CENTER WILL TRACK OVER LAND WITHIN THE NEXT SIX
HOURS AND CONTINUE TRACKING WEST-NORTHWESTWARD WITH STEADY
WEAKENING. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25
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 DOWNGRADED TO LOW. THIS CANCELS REF A
(WTIO21 PGTW 172030).//
NNNN
Sub: Depression over southwest Bay of Bengal off north Tamil Nadu coast.
The Depression over southwest Bay of Bengal off north Tamil Nadu coast moved westnorthwestwards with a speed of 18 kmph during past 6 hours and lay centred at 1730 hrs IST of
today, the 18
th November 2021, over southwest Bay of Bengal off north Tamil Nadu coast, near
Lat. 11.8°N and Long. 80.9°E, about 150 km south-southeast of Chennai, 120 km eastsoutheast of Puducherry and 150 km east-northeast of Karaikal . It is very likely to continue to
move west–northwestwards and cross north Tamilnadu & adjoining south Andhra Pradesh
coasts between Puducherry & Chennai by early morning of tomorrow, the 19
th November, 2021.
WTIO21 PGTW 172030
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 92B)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
140 NM EITHER SIDE OF A LINE FROM 10.4N 84.8E TO 12.5N 79.5E 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 25 TO 30 KNOTS. METSAT IMAGERY AT 172000Z
INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 10.6N 83.5E. THE
SYSTEM IS MOVING WESTWARD AT 13 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 92B) PREVIOUSLY LOCATED
NEAR 10.6N 83.5E IS NOW LOCATED NEAR 10.6N 83.5E, APPROXIMATELY 242
NM SOUTHEAST OF CHENNAI, INDIA. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY AND A 171614Z MHS 89GHZ MICROWAVE IMAGE DEPICT A
CONSOLIDATING SYSTEM WITH IMPROVED DEEP CONVECTIVE BANDING OVER THE
WESTERN SEMICIRCLE WRAPPING INTO A DISTINCT LLCC. A 171630Z ASCAT-B
IMAGE INDICATES AN ELONGATED, DEFINED CIRCULATION WITH 25-30 KNOT
WINDS OVER THE WESTERN SEMICIRCLE AND 20-25 KTS OVER THE EASTERN
SEMICIRCLE. ENVIRONMENTAL CONDITIONS ARE MARGINALLY-FAVORABLE WITH
MODERATE (15-20 KNOTS) EASTERLY VERTICAL WIND SHEAR OFFSET SOMEWHAT
BY STRONG DIFFLUENCE ALOFT. GLOBAL MODELS INDICATE A WEST-
NORTHWESTWARD TRACK WITH GRADUAL DEVELOPMENT AS THE SYSTEM
APPROACHES THE SOUTHEASTERN COAST OF INDIA. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 25 TO 30 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
182030Z.//
NNNN
(2) AN AREA OF CONVECTION (INVEST 92B) HAS PERSISTED NEAR
10.6N 83.5E, APPROXIMATELY 242 NM SOUTHEAST OF CHENNAI, INDIA.
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A LARGE CLUSTER
OF PERSISTENT DEEP CONVECTION OVER THE WESTERN SEMICIRCLE. A 171106Z
SSMIS 91GHZ COLOR COMPOSITE MICROWAVE IMAGE REVEALS A WEAKLY DEFINED
LOW-LEVEL CIRCULATION WITH DISORGANIZED DEEP CONVECTION SHEARED TO
THE WEST. RECENT ASCAT IMAGERY INDICATES AN ELONGATED CIRCULATION
WITH 15 TO 20 KNOT WINDS OVER THE NORTHERN SEMICIRCLE. ENVIRONMENTAL
CONDITIONS ARE MARGINAL WITH MODERATE TO STRONG (20-30 KNOTS)
EASTERLY VERTICAL WIND SHEAR OFFSET SOMEWHAT BY DIFFLUENCE ALOFT.
GLOBAL MODELS INDICATE A WEST-NORTHWESTWARD TRACK WITH SLOW
DEVELOPMENT. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO
20 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.
(1) THE AREA OF CONVECTION (INVEST 92B) PREVIOUSLY LOCATED
NEAR 10.2N 91.6E HAS DISSIPATED AND IS NO LONGER SUSPECT FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE IN THE NEXT 24 HOURS.