Hobart is in the midst of an extreme heatwave as hot air from the mainland gets pushed down south.

After temperatures already nudged 30 degrees on Wednesday and only just dipping below 18 degrees overnight, Hobart is in the middle of a firm and sweltering heatwave. By midday on Thursday, the mercury had already hit 34 degrees, a whopping 12 degrees above the January average. 

Luckily a weak seabreeze is expected in the city during the mid-afternoon, providing some needed relief. Thanks to this seabreeze and light winds overnight, the temperature is expected to drop to a mild 15 degrees, only three degrees above average.  

However, once the hot northerly winds start as the sun rises, the mercury will rise rapidly. A scorching 38 degree day is forecast on Friday, with some models suggesting the mercury may rise above 40 degrees. After temperatures rose to 40.8 degrees on 30th December 2019, it would only be the second time on record that Hobart has seen two 40 degree days in a season, the other occuring in the summer of 1897-98. 

Image: ECMWF temperatures showing the heat over Hobart and the rest of Tasmainia

Late in the day, thick clouds are expected to move overhead, trapping in the heat. A very hot night will ensue as temperatures will struggle to fall below 22 degrees in the early hours of the morning. This overnight minimum may also challenge the hottest night of 23.9 degrees recorded back in January 2018. However, some rain is expected during the nighttime, possibly making it feel colder than the actual temperature.

If all goes as forecast, the average temperature should be around 26.5 degrees during the 72 hour period. That would make this heatwave the fifth hottest in 137 years of records, behind Feb 1982 (28.4), Jan 1887 (27.6), Jan 1973 (27.0), and Dec 1994 (26.8).

A cool change is due around lunchtime on Saturday, switching the weather from above average to below average temperatures. Monday is only forecast to reach 16 degrees, six degrees below average.