AWIO20 FMEE 281139
BULLETIN FOR CYCLONIC ACTIVITY AND SIGNIFICANT TROPICAL WEATHER IN
THE SOUTHWEST
INDIAN OCEAN
DATE: 2011/03/28 AT 1200 UTC
PART 1 :
WARNING SUMMARY :
Nil.
PART 2 :
TROPICAL WEATHER DISCUSSION
:
A very weak transequatorial monsoon flow exists between 50E and 75E.
ITZC is well defined, stretching along 9S between 50E and 75E.
Convective activity is moderate between Seychelles and Mascareignes
Islands, and south-east of Chagos Islands, without any significant
low level circulation center.
East of 80E, basin is in a near equatorial trough pattern. A zone
of disturbed weather exists south of 10S, between 90E and 95E. Deep
convection remains fluctuating. Low level circulation center is
difficult to locate with accuracy. Position is estimated near
12S/91E at 11UTC. Minimal sea level pressure is estimated at
1004hPa. Center is moving westward. The European NWP model CEP
forecasts that the center will cross the 90E meridian during monday
to tuesday night. Trade inflow is good poleward, but monsoon inflow
is poor equatorward (westerly zonal monsoon flow north of the low).
Upper levels conditions are good (weak vertical wind shear and very
good poleward upper level divergence- cf. CIMSS analysis). SSTs are
favorable (>29 C). The poor monsoon inflow should be a limitant
factor for the deepening rate of the LLCC. Last CEP outcomes
forecast a slow deepening within the next 72 hours and a slow
movement westward for the next 24 hours, and quasi-stationnary
movement beyond J+1, system being wedged between two opposite
steering currents (westerly near equatorial current and easterly
current north of the subtropical ridge).
For the next 72 hours,
potential for development of a tropical depression is fair East of
the basin.

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