THE AREA OF CONVECTION (INVEST 91S) PREVIOUSLY LOCATED NEAR
10.0S 88.3E IS NOW LOCATED NEAR 10.0S 88.8E, APPROXIMATELY 493 NM WEST-
NORTHWEST OF THE COCOS ISLANDS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS STEADILY BUILDING CONVECTION ASSOCIATED WITH A COMPACT
LOW LEVEL CIRCULATION. A 021504Z METOP-B SCATTEROMETRY IMAGE VERIFIES
THAT A DEVELOPING CIRCULATION EMBEDDED WITHIN THE SOUTHERN MONSOON TROF
IS CONSOLIDATING, AND DEEPENING CONVECTION AROUND THE SYSTEM.
ENVIRONMENTAL ANALYSIS REVEALS FAVORABLE CONDITIONS FOR DEVELOPMENT WITH
LOW TO MODERATE VERTICAL WIND SHEAR (10-15 KTS), WARM SEA SURFACE
TEMPERATURES (28-29 C), AND GOOD POLEWARD AND EQUATORWARD OUTFLOW ON THE
WESTERN PERIPHERY BUT RESTRICTED OUTFLOW ON THE EASTERN SIDE. GLOBAL
DETERMINISTIC AND ENSEMBLE MODELS SHOW GOOD AGREEMENT ON STEADY
CONSOLIDATION OVER THE FOLLOWING COUPLE OF DAYS WITH ALL MODELS SHOWING
DEVELOPMENT. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN
THE NEXT 24 HOURS REMAINS LOW.
THE AREA OF CONVECTION (INVEST 91S) PREVIOUSLY LOCATED NEAR
10.0S 88.8E IS NOW LOCATED NEAR 8.7S 89.9E, APPROXIMATELY 465 NM WEST-
NORTHWEST OF THE COCOS ISLANDS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A CONSOLIDATING COMPACT LOW LEVEL CIRCULATION CENTER
(LLCC) EMBEDDED WITHIN PERSISTENT CONVECTION. ENVIRONMENTAL ANALYSIS
REVEALS FAVORABLE CONDITIONS FOR DEVELOPMENT MOVING FORWARD WITH LOW TO
MODERATE (10-15 KTS) VERTICAL WIND SHEAR FROM THE NORTHEAST, WARM (28-29
C) SEA SURFACE TEMPERATURES, AND GOOD POLEWARD OUTFLOW ON THE WESTERN
PERIPHERY OF THE SYSTEM WHILE BEING SLIGHTLY RESTRICTED ON THE EASTERN
SIDE. GLOBAL DETERMINISTIC AND ENSEMBLE MODELS ARE IN GOOD AGREEMENT 91S
WILL CONTINUE TO TRACK SOUTHEASTWARD WITH STEADY INTENSIFICATION OVER
THE NEXT 24-48 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 UPGRADED TO MEDIUM.
Tropical Low 11U to impact Cocos (Keeling) Islands as it passes close by on Monday.
Area affected
Warning zone
None.
Watch zone
Cocos (Keeling) Islands.
Cancelled zone
None.
At 12:30 am Cocos Islands Time
At 12:30 am CCT
Intensity
tropical low, sustained winds near the centre of 75 kilometres per hour with wind gusts to 100 kilometres per hour
Location
within 55 kilometres of 8.0 degrees South, 90.9 degrees East and 800 kilometres northwest of Cocos (Keeling) Islands
Movement
east northeast at 19 kilometres per hour
Tropical Low 11U is developing well to the northwest of the Cocos (Keeling) Islands. It is expected to move eastwards during Sunday, before turning southeast and then southwards on Sunday night.
This movement will bring the low close to the Cocos (Keeling) Islands on Monday with an increasing chance of gales developing during the day on Monday.
Hazards
Gales and heavy rain are not expected over the Cocos (Keeling) Islands during Sunday but will develop during Monday as Tropical Low 11U approaches the islands from the north.
Recommended action
Ensure you know what to do in a cyclone. For the latest community alerts and warnings visit www.emergency.wa.gov.au or download the Emergency WA app.
WTXS21 PGTW 031800
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91S)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 8.0S 91.5E TO 10.7S 96.9E
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 27 TO 32 KNOTS. METSAT
IMAGERY AT 031800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 8.1S 91.6E. THE SYSTEM IS MOVING EAST-NORTHEASTWARD AT 18
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 91S) PREVIOUSLY LOCATED NEAR
8.7S 89.9E IS NOW LOCATED NEAR 8.1S 91.6E, APPROXIMATELY 395 NM
NORTHWEST OF THE COCOS ISLANDS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS PERSISTENT CONVECTION OVER THE NORTHERN PORTION OF A
CONSOLIDATING, COMPACT LOW LEVEL CIRCULATION CENTER (LLCC) EVIDENT IN A
031440Z METOP-B ASCAT PASS. ENVIRONMENTAL ANALYSIS REVEALS FAVORABLE
CONDITIONS FOR DEVELOPMENT WITH LOW TO MODERATE (10-15 KTS)
NORTHEASTERLY VERTICAL WIND SHEAR, WARM (28-29C) SEA SURFACE
TEMPERATURES, AND FAVORABLE POLEWARD AND WESTWARD OUTFLOW ALOFT. GLOBAL
DETERMINISTIC AND ENSEMBLE MODELS ARE IN GOOD AGREEMENT THAT 91S WILL
CONTINUE TO TRACK SOUTHEASTWARD AND STEADILY INTENSIFY OVER THE NEXT 24-
48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 27 TO 32
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 HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
041800Z.//
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