The Western Cape in all its districts received more rain in January (slide 1) than during December last year though the western parts (especially the coastal areas and Swartland) only received 10mm and less. Rainfall conditions improved more to the eastern side of the province with higher precipitation in northern and eastern parts of the Central Karoo (>50mm) as well as the coastal and adjacent areas of Eden (George 106mm).
The good rainfall conditions of January 2016 are highlighted when compared to the historical long term means (slide 2). With more than half of the province indicating above normal rainfall conditions, below normal rainfall conditions remained in parts of the West Coast, Cape Winelands, Overberg, western side of the Central Karoo and the area surrounding Oudtshoorn.
Slide 3 contains data representing 38 weather stations consisting of total monthly rainfall, mean monthly maximum (Tmax) and minimum temperatures (Tmin) for January 2016 and long term means. From the above description we expect most weather stations to indicate above normal rains for January (Citrusdal, George, Merweville, Porterville, Prince Albert, Riversdale, ect.) and the drier areas represented by poor (Piketberg 4mm) to no rain (Oudtshoorn).
The average Tmax (calculated from the separate monthly means of the 38 weather stations) during January this year (slide 3) was 1.9ºC higher compared to the calculated combined long term figure. Note that the latter long term figure was 2ºC higher than in the case of December. The monthly Tmax means for January 2016 (taken from 38 weather stations) ranged between 25.2ºC and 38.5ºC vs. LT range of 24.6 – 36.2ºC. Except for George, each monthly Tmax mean (per weather station) for January 2016 was higher than the corresponding long term mean, even extreme cases exceeding by 3ºC+ (Citrusdal, Hopefield, Koue Bokkeveld, Langgewens, Oudtshoorn, Sandveld and Elsenburg).
The average Tmin of 17.8ºC indicate an average overall increase of 2ºC compared to calculated combined long term figure. The monthly Tmin means (taken from 38 weather stations) ranged between 14.4 and 21.6ºC (vs. LT 12.2 – 19.8ºC). Additionally most monthly Tmax means for January 2016 was higher than their long-term means, extreme cases even 2ºC+ higher (Misgund & George).
The overall dam level of 46% (2th February) decreased by 7 percentage points from the previous month’s figure which was mainly caused by declining water levels of dams situated more to the western side of the province (Clanwilliam, Theewaterskloof, Voëlvlei, ect.). Dams located more to the east (especially the Gamka Dam) increased substantially. The Floriskraal and Clanwilliam dams are for some time a major challenge with regard to extremely below-normal water levels.
Plant growing conditions (slide 5) remained poor in the West Coast and Central Karoo due to current dry conditions. Along the southern coastal parts plant activity appeared more promising.
ENSO still shows strong El Niño conditions (slide 6) though the following months indicate ENSO progressing towards neutral status by May 2016. For the period March to May SAWS forecasts below normal rains in summer rainfall areas in the Western Cape (slide 7). A much higher probability exists for above normal temperatures during the same period in the Western Cape.
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