Pretoria — The South African Weather Service (SAWS) says severe tropical storm "Dineo" is quite likely to undergo a final surge of intensification, just before arriving over land in Mozambique this evening.
There is also a good chance that it will reach tropical cyclone status within the next six to 12 hours.
"Given that Dineo is likely to reach tropical cyclone intensity during today, the projected maximum strength of surface winds associated with the system will be 70 knots, or about 130km/h.
"While this wind strength is somewhat weaker than the earlier estimate of 160 to 170km/h, this is still a formidable storm system, which has the potential to cause much damage to coastal and inland infrastructure," said the weather service on Wednesday.
A concern for communities in southern Mozambique will be heavy or torrential rain resulting in widespread flooding. Sea conditions along the southern Mozambican coast are forecast to be very rough.
"Assuming landfall near Massinga and Inhambane, the coastline north of Xai-Xai, will be particularly vulnerable to storm surge," said SAWS.
On Thursday, Dineo is expected to migrate due west, still as a significant rain-bearing system but starting to weaken significantly.
The lower portion of the Limpopo River flows directly through the Mozambican region that is most likely to be severely affected. This compounds the risk of flooding for communities which may possibly be displaced by this event.
Regarding direct, weather-related impacts for South Africa, the weather service said, heavy rainfall may occur in places over the northern Lowveld and adjacent escarpment regions of Limpopo on Thursday evening.
"The greatest impact, with respect to South African provinces, is suggested to be overnight Thursday and into the morning hours of Friday the 17th, when heavy rain can be expected over the entire eastern half of Limpopo, including the Kruger National Park, where 100 to 200mm of rain could occur per day.
"By early Friday morning, the surface vortex (core) of Dineo should begin dissipating in the region of Musina and Beit Bridge in the northern part of Limpopo province."
SAWS said by Saturday, the remnants of Dineo are expected to drift into Botswana and showers are expected to continue over Limpopo.
"Rivers in the region will continue to flow quite strongly in the latter part of the weekend and into next week, as overland runoff takes some time to enter river systems.
SAWS said it was important to remember that such tropical systems, which originate over open water, are critically dependent on the open ocean as a source of latent heat energy in order to sustain their growth and intensification.
"The moment such systems move overland (as is the case with Dineo later today), they invariably undergo rapid structural weakening and decay," the weather service said.
SAWS will continue to monitor any further developments relating to this weather system and will issue updates as required.