After a lull in recent weeks, storm season in the US has begun to ramp up again, with 100mph winds and tennis ball-sized hail hitting Kansas on Sunday. It has been a busy season so far in terms of severe storms, with late spring into early summer typically bringing the greatest risk for tornadoes across the plains and midwest. An area of low pressure moving in across the central US, combined with rich moisture streaming in from the Gulf of Mexico, will probably continue the threat of tornadoes and large hail across numerous states. On Tuesday in particular, this severe weather risk may extend from Oklahoma all the way up to the Great Lakes.
This setup of low pressure could lead not just to a large outbreak of severe weather across the US later this week, but also to a sharp temperature gradient across the US and Canada as the warm air is fed into higher latitudes. In eastern Canada and the north-eastern US, temperatures are likely to reach 10C above the average for the time of year. Cities such as Ottawa and Detroit could have daytime maximum temperatures of 30C by Wednesday.
Yet move into western areas of Canada and the US, and you’ll see temperatures plummet nearly 20C on the other side of the cold front – this helped by the central area of low pressure over the US simultaneously pulling down the colder air to lower latitudes. The maximum temperatures are expected to struggle to reach into double digits on Wednesday and Thursday, before temperatures recover closer to the average for all parts of the North American continent.
South America will have similarly wild swings in temperature. While parts of Brazil and Paraguay will see temperatures 6-8C above the average, large swathes of Chile and Argentina will be having their first taste of winter later this week as temperatures are predicted to fall over 10C below the norm. In Argentina especially, daytime maximum temperatures are unlikely to reach double figures, with the city of Mendoza potentially struggling to reach 5C on Friday 24th – about 13C below the average. There will be little relief through the weekend as the cold conditions look to persist into next week.
