Tropical Cyclone Bongwe

[Somerset Squall]

The south indian ocean has certainly woken up- Tropical Cyclone Lee-Ariel is dissapating but already another TC has formed, TC 04S (soon to be Bongwe).

The storm is well out to sea at the moment and is heading generally southwards although a more westward turn is predicted later in the forecast period. 04S is certainly a large storm so intensification isn't going to be rapid but conditions certainly are ripe for intensification. Outflow is excellent, shear is low and sea temps are sufficiently warm. Banding features are already evident, indicative of a strengthening cyclone. If the favourable conditions persist, we could well end up with a pretty big storm in the coming days. 04S is no threat to land at the moment, but if the westwards track does materialise and the conditions continue to be favourable, then it could end up getting close to Madagascar. This is a long way off though and there is now way of telling if this is likely to occur as yet- but still, it's one to watch.

Satellite image of 04S (with a decaying Lee-Ariel to it's southeast), you can see it's a large storm:

http://cimss.ssec.wisc.edu/tropic/real-tim...ges/images.html

[Somerset Squall]

Bongwe briefly reached 65kt cat 1 status but has now ingested dry air and has weakened to 55kt. Once Bongwe manages to mix out this dry air, high sea temps and excellent outflow should aid the intensification to resume. Bongwe will continue it's southwestward track around the periphery of a subtropical ridge to the southeast. Bongwe is not a threat to land- yet.

[Somerset Squall]

Bongwe has continued to weaken this morning as dry air wraps itself around the system, 45kt is the current intensity. The dry air is not forecast to kill the cyclone as it has warm sea temps and low shear on it's side, but it's forecast to roughly maintain this intensity throughout the forecast period (with a small fluctuation up or down).

Bongwe is still tracking west-southwestward under the influence of a subtropical HP to the south of the storm. This motion is expected to continue, maybe with a more westaward turn later.

[Somerset Squall]

Bongwe has managed to recover a little since my last posting, and now has sustained winds of 55kt. It really looks a lot better than this time yesterday, the storm has consolidated and has tight banding wrapped around the centre. However, it's not likely to re-strengthen any further due to continued ingestion of dry air and the fact that Bongwe has moved over cooler waters. This may sound like a recipe for dissapation but the effects are weighed out by excellent outflow and the fact the waters are still just about sufficent to support a tropical cyclone.

Steering from now on has become a lot more complicated. Bongwe has been moving west-southwestwards at moderate speed over the last 24 hours. Bongwe is expected to slow considerably as an equatorial ridge to the northeast and a subtropical ridge to the south compete for steering influence. This will make Bongwe amble westwards for the duration of the forecast period, it may even become quasi-stationary at times.

It's worth noting that this storm has travelled a good deal to the west since it's birth and is bearing down on Madagascar, Reunion and Mauritius. It is not certain whether Bongwe will make it that far but it's still worth watching over the coming days.

[Somerset Squall]

Bongwe is on the verge of giving up. Shear has increased over the cyclone and the LLC is now nearly entirely exposed. Sustained winds have dropped to 40kts and it is likely Bongwe will dissapate within the next 48 hours.

[Somerset Squall]

Bongwe dissapated a few days ago but the JTWC have flagged up the small possibility of Bongwe regenerating over the next couple days:

SOUTH INDIAN OCEAN AREA (135E WEST TO COAST OF AFRICA):

A. TROPICAL CYCLONE SUMMARY: NONE.

B. TROPICAL DISTURBANCE SUMMARY:

(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 12.8S 65.6E,

IS NOW LOCATED NEAR 13.3S 63.3E, APPROXIMATELY 655 NM WEST-SOUTHWEST

OF DIEGO GARCIA. THE SYSTEM IS THE REMNANTS OF TROPICAL CYCLONE 04S

(BONGWE). THE LOW LEVEL CIRCULATION CENTER REMAINS FAIRLY DEFINED IN

RECENT MULTISPECTRAL SATELLITE IMAGERY, HOWEVER, THE SYSTEM LACKS

CONVECTION. DUE TO DVORAK INTENSITY ESTIMATES OF 25 KNOTS AND THE

WELL DEFINED CIRCULATION CENTER, THE POTENTIAL FOR THE DEVELOPMENT OF

A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS POOR.

(2) NO OTHER SUSPECT AREAS.

FORECAST TEAM: DELTA//

NNNN

[Cookie]

I take it that it didnt then?

its strange I never go any tropical storm alarts for this.

[Somerset Squall]

I take it that it didnt then?

its strange I never go any tropical storm alarts for this.

Yes, it didn't regenerate after all and it's remnants have finally reached Madagascar.

Am I right in saying your storm alert gives you warnings when a storm threatens land? If this is the case it wouldn't have given you an alert because Bongwe never threatened land. If it had survived longer then it may well have done but fortunately not in this case.

[Cookie]

ahh right. sometimes it wired like that