Dear weather-watchers,


It’s been a while…. and before the winter ends, it is time for a weather update and a look at the coming rainy season..!

Swakopmund

• Swakopmunders had a cool start of 2024, which is normal when we have a poor rainy season upcountry. May and June have been pleasantly warm due to the east winds, although they didn’t reach the wind speeds of previous years (at least not in downtown Swakopmund).

• In terms of east wind frequency we are had a pretty normal run-up this winter but we are currently three days below the average for mid-July.

• Rainfall in Swakopmund for the past rainy season (Sept to May) came to only 5 mm, which was undercut only by the 2003/2004 rainy season (which registered 4.8 mm).


Windhoek

• Windhoekers had a very warm start of the year due to the poor rains (and in turn due to the strong El Nino). Temperatures in January to April were about 2 C higher than average as a result.

• The rainy season in Windhoek ended at a really dismal 46.2 mm according to the Sasscal weather station at the National Botanical Institute on the hill. I am sure other places in Windhoek received more rain than this. However across the country rains were poor and resulted in very low water levels in most dams across the country and in the food crisis we are dealing with now.

• Winds were consistently stronger than usual since the start of the year.



ENSO News and the outlook for the 2024/25 rainy season


Pages 4, 5 and 6 show, as usual, the most important indicators for our coming rainy season (in my opinion):

Pages 4 and 5 show the latest groups of model runs for the predicted sea surface temperature anomalies of the Central Pacific ocean. Both model runs show that the El Nino (which is the abnormal warming of the Central Pacific ocean) has now ended and that we are heading for a weak La Nina for the period of August to February (i.e. a slight abnormal cooling of this ocean region). The La Nina is predicted to peak around -0.8 C. This is good news for us, as it means less convection (rising air) over the Central Pacific and more convection over the other side of the globe, which includes Southern Africa.

Note though that

(a) The La Nina is only half as intense as the El Nino was during the last rainy season, so its effect will be muted.

(b) The La Nina is forecast to revert back towards neutral in the second half of the rainy season.

(c) The Indian Ocean Dipole (IOD) is forecast to remain neutral during the coming season (page 6), so no unusual amounts of moisture from the western Indian Ocean can be expected.


Pulling all these main indicators together I am expecting a slightly better than normal rainy season for 2024-25.


With best wishes to your all,
Klaus