southern indian ocean Moderate Tropical Storm Glenda

[tropicbreeze]

A tropical low has formed in the Indian Ocean putting the island of Rodrigues under the spotlight again. However, it is not expected to directly impact the island.

At 0600 UTC position South 14.0 East 74.9, central pressure 1002 hPa, movement south west at 5 knots, wind speed (10 minute) 25 knots.

Global Models 0000z 20150223


RMSC La Reunion track map 0600 UTC 20150223

[tropicbreeze]

The system is experiencing decreasing vertical wind shear with strengthening convection near the centre. It's expected to intensify to tropical cyclone strength in 48 hours. However, in 72 hours increasing vertical wind shear is expected to commence weakening the system.

At 0600 UTC 20150224 central pressure 996 hPa, position South 16.1 East 71.9, movement west at 6 knots, wind (10 minute) 30 knots.

[Somerset Squall]

The system has been named Glenda by MeteoFrance. Winds have increased to 40kts (1-min sustained). Convection has built quite nicely over Glenda's LLCC, and good banding features flank the storm. As shear is lessening and outflow is good, further intensification is likely as Glenda heads

southwestwards along the northwestern periphery of a ridge to the southeast. As Glenda reaches a weakness in the ridge in a few days time, a turn to the south is expected. At this stage, waters cool along track which will produce weakening. Until then, the environment looks favourable.

Edited February 24, 2015 by Somerset Squall

[Somerset Squall]

Glenda appears to be strengthening quickly. Winds are up to 55kts according to JTWC. The storm now has a well established central dense overcast, with continued strong banding. Based on current trends, I think Glenda could well become a 100kt+ cyclone (1 min sustained) before it's done.

[tropicbreeze]

Glenda is tracking west but is expected to swing polewards soon and then south south eastwards. Vertical wind shear is low with equatorial outflow very good in the upper levels and a poleward outflow channel expected to develop soon. However the system is struggling to consolidate deep convection around the centre. Intensification to a tropical cyclone is expected in 24 hours.

At 0600 UTC 20150225 central pressure 989 hPa, position South 17.6 East 68.9, movement west at 10 knots, wind (10 minute) 45 knots, radius of maximum winds 157 kms.

[tropicbreeze]

RMSC La Reunion has now downgraded the possibility of Glenda developing into a tropical cyclone. Although wind shear remains low dry air has wrapped into the system from the west. There are recent signs of disorganisation and weakening. The system is expected to become post tropical in 60 hours.

At 0000 UTC 20150225 central pressure 991 hPa, position South 19.9 East 68.0, movement south south west at 10 knots, wind (10 minute) 40 knots, radius of maximum winds 148 kms.

[Somerset Squall]

Indeed, dry air has significantly affected Glenda, looks like we won't see much more strengthening with this storm now. Winds are still at 55kts (1-min sustained) and JTWC are only forecasting a peak of 65kts now.

[tropicbreeze]

Vertical wind shear from the west has increased and is expected to continue doing so. The system will swing to the south south east and should commence extra tropical transition in 24 hours. JTWC has finally fallen in line with RMSC La Reunion's assessment. Monday it should pass to the south of Amsterdam and St Paul Islands which for most of the time are unoccupied, apart from the occasional presence of scientific researchers.

At 0600 UTC 20150227 central pressure 980 hPa, position South 23.6 East 66.8, movement south at 7 knots, wind (10 minute) 45 knots, radius of maximum winds 157 kms.

[tropicbreeze]

Ex-Glenda un undergoing extra tropical transition. The LLCC is fully exposed and a warm front lies over the southern part of the system. Deep convection has disappeared from the northern sector.

At 1200 UTC 20150227 central pressure 972 hPa, position South 29.6 East 68.1, movement south at 18 knots, wind (10 minute) 50 knots, radius of maximum winds 185 kms.