The ACT State Emergency Service has warned Canberrans to prepare for heavy rain and possible thunderstorms, with up to 60 millimetres of rain predicted for Friday.
The Bureau of Meteorology said the rain would start mid to late Thursday morning and progressively intensify, with the heaviest falls expected on Friday.
''It's going to be quite unstable, so the potential exists for the odd severe thunderstorm,'' the bureau's duty forecaster said.
''On the forecast, we've got 15 to 20 millimetres-plus on Friday, with the potential for up to 60mm around the traps. On Thursday, not so much [is expected]; between five and 15mm.''
The SES has advised people to take care in light of the forecast. ''In the event of significant rainfall from thunderstorm activity, the ACTSES advises to avoid walking, riding or driving through fast-flowing water and to ensure children do not play near stormwater systems,'' it said.
It also asked residents to check their gutters and drains were clear, and reminded people to have regular roof maintenance by contractors ''with particular attention to skylights, airconditioning units or other roof additions''.
The good news is the rain should ease on Saturday with a few showers, before fine weather returns for Sunday and Monday.
A maximum of 24 degrees is expected on Thursday, dropping to 17 degrees on Friday before climbing to a steady 21 degrees into early next week.