Another round of heat will be making its ways across SA, VIC, TAS and western NSW from today until the weekend. Have you ever wondered why? In Adelaide, temperatures will be on the rise from today peaking in the mid 40s on Saturday before a cool change early on Sunday. The cool relief, however, will not last as temperatures will gradually increase again next week reaching the mid 40s yet again by Thursday. Melburnians will experience similar conditions, with temperatures in the high 30s on Saturday before a late-morning/midday cool change on Sunday. Temperatures will then gradually raise early next week, reaching the mid 30s by Thursday 13th before yet another cool change. Our nation's capital will nudge the 40s by Sunday and the mid 30s later next week, with Hobart nudging the 30s on Sunday, nearly ten degrees above their long term average. The reason, a stubborn high pressure system over the Tasman Sea. This high is currently traveling east over Tasmania but will stall over the Tasman later tonight and will barely move over the next 10 days. This high will: 1) direct hot northerly winds across southern Australia (winds turn anti-clockwise around a high) dragging a hot airmass from the central interior (Australia's heat engine) towards the coast. 2) lead to mostly clear skies across the south allowing for sunny conditions to heat the airmass even further. 3) prevent any significant cold fronts from crossing the south to flush the heat away (hence these kind of highs are also called blocking highs). This same high, responsible for hot temperatures in the south, will bring onshore winds and allow for afternoon sea breezes along the eastern seaboard. This will moderate temperatures east of the Great Dividing Range and hold temperatures to the high 20s and low 30s. This high will eventually budge, but temperatures are likely to remain above average in the south through February with no strong fronts in sight. This follows the warm trend observed across most of the country in the past year.