WTIO30 FMEE 041900
RSMC / TROPICAL CYCLONE CENTER / LA REUNION
TROPICAL CYCLONE FORECAST WARNING (SOUTH-WEST INDIAN OCEAN)
0.A WARNING NUMBER: 2/3/20212022
1.A MODERATE TROPICAL STORM 3 (CLIFF)
2.A POSITION 2022/02/04 AT 1800 UTC:
WITHIN 30 NM RADIUS OF POINT 18.7 S / 83.5 E
(EIGHTEEN DECIMAL SEVEN DEGREES SOUTH AND
EIGHTY THREE DECIMAL FIVE DEGREES EAST)
MOVEMENT: SOUTH-WEST 3 KT
3.A DVORAK ANALYSIS: 3.0/3.0/D 0.5/6 H
4.A CENTRAL PRESSURE: 994 HPA
5.A MAX AVERAGE WIND SPEED (10 MN): 40 KT
RADIUS OF MAXIMUM WINDS (RMW): NIL
6.A EXTENSION OF WIND BY QUADRANTS (KM):
28 KT NE: 150 SE: 405 SW: 480 NW: 95
34 KT NE: 0 SE: 335 SW: 260 NW: 75
7.A FIRST CLOSED ISOBAR (PRESSURE / AVERAGE DIAM): 1005 HPA / 1900 KM
8.A VERTICAL EXTENSION OF CYCLONE CIRCULATION: DEEP
DURING THE LAST 6 TO 12 HOURS, CONVECTION HAS CONTINUED TO DEVELOP
NEAR THE LOW'S CENTER, EVOLVING INTO A CURVED BAND PATTERN. THE 0759Z
AMSR2 AND 1303Z SSMIS PASSES CONFIRM THIS IMPROVED ORGANIZATION. THE
1626Z ASCAT PASS SHOWS A WIND AXIS REACHING UP TO 40KT IN THE SOUTHERN
SEMICIRCLE. TROPICAL DEPRESSION 03-20212022 HAS THUS BEEN UPGRADED TO A
MODERATE TROPICAL STORM AND NAMED CLIFF AT 1430UTC BY MAURITIUS
METEOROLOGICAL SERVICE. A COMPROMISE BETWEEN DVORAK SUBJECTIVE
ANALYSIS (DT BETWEEN 2.5 AND 3.0 BASED ON A CURVED BAND PATTERN) AND
ASCAT MEASUREMENTS ENABLES US TO ESTIMATE CLIFF'S MAXIMUM WINDS AT
40KT, LOCATED IN ITS SOUTHERN SEMICIRCLE.
CLIFF IS MOVING SLOWLY SOUTH-SOUTH-WESTWARD IN THE SHORT TERM, THEN
WILL MOVE MORE FRANKLY TO THE SOUTH-WEST TO WEST-SOUTH-WEST WHILE
ACCELERATING IN THE NEXT FEW DAYS, UNDER THE INFLUENCE OF STEERING
FLOWS GENERATED BY SEVERAL RIDGES SURROUNDING THE SYSTEM ON ITS
NORTH-EAST, SOUTH-EAST AND SOUTH SECTORS. ITS TRACK LEAVES IT FAR FROM
INHABITED LANDS.
THE CURRENT WINDOW OF INTENSIFICATION ASSOCIATED AMONG OTHER THINGS
WITH GOOD UPPER DIVERGENCE AHEAD OF AN APPROACHING JET, AND WHICH
ALLOWED TROPICAL STORM CLIFF TO FORM, SHOULD CLOSE FAIRLY QUICKLY.
FROM THIS SATURDAY ONWARDS, INCREASING NORTHWESTERLY SHEAR SHOULD
FORCE INTRUSION OF DRY AIR FROM THE WESTERN SIDE OF THE SYSTEM AND
SHOULD WEAKEN THE SYSTEM DURABLY.
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
100 NM EITHER SIDE OF A LINE FROM 16.9S 83.7E TO 20.1S 82.9E
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 25 TO 30 KNOTS. METSAT
IMAGERY AT 040000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 17.2S 83.6E. THE SYSTEM IS MOVING SOUTHWARD AT 07 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 90S) PREVIOUSLY LOCATED
NEAR 16.5S 83.6E IS NOW LOCATED NEAR 17.2S 83.6E, APPROXIMATELY 871
NM SOUTHEAST OF DIEGO GARCIA. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS DEEP FLARING CONVECTION PARTIALLY OBSCURING AN
ELONGATED LOW LEVEL CIRCULATION (LLC). RECENT SCATTEROMETRY DATA
REVEALS WINDS OF UP TO 30 KNOTS OFFSET TO THE SOUTH OF THE LLC.
ENVIRONMENTAL ANALYSIS INDICATES FAVORABLE CONDITIONS FOR
DEVELOPMENT DEFINED BY; ROBUST OUTFLOW ALOFT, LOW TO MODERATE (15-
20KT) VERTICAL WIND SHEAR, AND WARM (28-29C) SEA SURFACE
TEMPERATURES. GLOBAL MODELS ARE IN AGREEMENT THAT INVEST 90S WILL
CONTINUE TO INTENSIFY AS IT TRACKS EQUATORWARD BEFORE TURNING TO A
MORE WEST-SOUTHWESTWARD TRACK AROUND TAU 36. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS HIGH.