High pressure is moving in today over SA and will move towards the southeast and east during Monday and Tuesday, that will keep the frost going, possibly severe over pockets of the east during Tuesday and Wednesday morning.
Cold air left over following a low pressure system passing through Bass Strait will linger until about Tuesday before mixing out and warmer air filtering in with a northwest flow developing through SA Tuesday and then the southeast and east from Wedensday.
Fog Risk Forecast for Monday morning - Valid Sunday 4th of July 2021.
Fog likely about the ranges over the southeast with a light wind airmass closer to the centre of high pressure. Some of those fog patches will be quite heavy at times where the winds are lighter. Drier air over the plains will reduce the risk of heavy fog for Monday but the risk increases mid week.
Frost Risk Forecast for Monday morning - Valid Sunday 4th of July 2021.
A dry cold airmass in place will allow temperatures to freely fall this evening once the sun goes down with clear skies and light winds in place. That will set the stage for a frosty start for large areas of the east, heavier over elevation and about parts of the western and southern inland. Temperatures will warm steadily through the morning.
There may be some regional aviation delays with the fog patches through inland parts on Monday morning so some light aircraft may be delayed in these conditions, but with a moderate wind profile the fog should lift fairly quickly, but may linger during Tuesday and Wednesday.