Update: Advisory - Possible Cut-off low predicted for the Southern Cape 13-16 Jul 2012

PREPARE FOR A SEVERE WEATHER SYSTEM IN SOUTH AFRICA

VERY COLD CONDITIONS WITH UNSEASONAL HEAVY RAINFALL EXPECTED IN SOME AREAS

South Africans should prepare themselves for severe weather that is expected to bring very cold weather with widespread, unseasonal rainfall that is likely to be heavy in some areas of the Western Cape, Southern Cape and Eastern Cape. Severe thunderstorms with strong wind is likely to set in over parts of the North West and Free State Provinces by tomorrow. While heavy snowfalls are expected on the high mountains of the Western Cape, Northern and Eastern Cape on Friday night and Saturday, at present the main feature of this weather system is the risk of heavy rainfall and flash flooding in the Western Cape, Southern and Eastern Cape.

Significant snowfalls are likely on the mountains of Lesotho, the Drakensberg, and the north-eastern high ground of the Eastern Cape. Very windy conditions are expected in many parts of the interior on Friday, Saturday and Sunday.

There is presently uncertainty about the behaviour of this weather system as it develops. The following satellite images clearly indicate how the system developed in the last 48 hours.

SA Weather Satellite Images: 11 July 2012 16h00 SAST

The next two images downloaded at 16h00 today clearly illustrate how the system developed.

SA Weather Satellite Images: 12 July 2012 16h00 SAST

This mornings GFS models reflect the areas where heavy rainfall is expected. The area of heavy rainfall has been increased in the latest predictions.

Image: GFS Medium Range Forecasts of Vertical Velocity and Precipitation. (Click on image for larger view.)

Snow is also expected in parts of the Western/Southern/Northern and Eastern Cape provinces and Lesotho as of Friday, 13 July 2012. Heavy snowfall over parts of the Eastern Cape and Lesotho can be expected on Saturday, 14 July 2012. Temperatures are expected to plummet below zero with very cold conditions setting in. As per usual several mountain passes and roads will be closed to traffic in the event of heavy rain, snowfall or icy and waterlogged road conditions.

Images: Snow-forecast.com (Click on images for larger view.)

South Africans should prepare themselves for a significant severe weather system. The SAWDOS is currently monitoring this system very closely and will bring you the latest updates.

We also remind our readers that the SAWDOS utilize the following social media formats to keep our readers informed :

SA Weather and Disaster Observation Service Blog - http://sawdis1.blogspot.com/

SAWDOS Twitter - http://sawdis1.blogspot.com/p/sawdis-twitter.html or @SAWDOS1

SAWDOS Facebook Group - http://www.facebook.com/groups/374316165928426/

Please note that any of the above could be used during severe weather to keep the public informed or to notify the SAWDOS of a severe weather event.

Johan Terblanche
Founder: SA Weather and Disaster Observation Service
Mossel Bay
12 Julie 2012