After prolonged heavy rainfall and devastating flooding across the Pacific north-west in the past few weeks, further flood watches have been issued across California through this week.
With 50-75mm (2-3in) of rainfall already reported across northern California this weekend, a series of atmospheric rivers will continue to bring periods of heavy rain and mountain snow across the northern and central parts of the state, with flood watches extending until Friday.
Cumulative rainfall totals are expected to widely exceed 50mm (2in) across a vast swathe of California by Boxing Day, but with totals around 200-300mm (8-12in) possible for the north-western corner of California and western-facing slopes of the northern Sierra Nevada mountains.
Los Angeles could receive 100-150mm (4-6in) of rainfall between Christmas Eve and Christmas Day, which could make it one of the wettest Christmases on record for the city. River and urban flooding are likely – particularly where there is run-off from high ground – with additional risks of mudslides and rockslides in mountain and foothill areas.
Winter storm warnings are also in effect for Yosemite national park, with the potential for 1.8-2.4 metres (6-8ft) of accumulating snow by Boxing Day. Heavy snow alongside strong winds will make travel very difficult over the festive period.
Heavy rain, lightning and strong winds are forecast across large parts of Zimbabwe leading up to Christmas. A level 2 weather warning has been issued by the Meteorological Services Department from Sunday 21 December to Wednesday 24 December. Some areas are expected to see more than 50mm of rainfall within a 24-hour period. The rain will be accompanied by hail, frequent lightning, and strong winds. These conditions have been attributed to the interaction between warm, moist air with low-pressure systems over the western and northern parts of the country.
Australia will see some large variations in temperatures over the festive period. Sydney, which is experiencing temperatures above 40C, is expected to tumble down to about 22C by Christmas Day, about 5C below average for this time of year. Perth is going to see temperatures gradually creep up, reaching a peak of 40C around Christmas Day. This is about 10C above average for this time of year.
