A rainfall warning and severe thunderstorm watch have gone out for most of western Quebec Tuesday and early Wednesday, with areas west of Quyon getting both. Heavy rain may also hit Renfrew County.
Environment Canada’s severe thunderstorm watch covers the Outaouais, except for Gatineau and its easternmost communities such as Grenville.
Along with the lightning, it forecasts strong wind gusts, hail and heavy rain through evening. Places east of that Quyon dividing line could get 20 to 40 millimetres of rain and to the west, about 50 millimetres.
Those more western communities are under the rainfall warning.
If a few thunderstorms hit, more rain than that could fall. The warning floats 75 millimetres of rain as a possibility.
Renfrew County has a special weather statement about 60 millimetres as the top-end forecast from late afternoon into Wednesday. A significant amount of that could fall in an hour and trigger a rainfall warning there.
Pembroke’s daily rainfall record of about 26 millimetres on Aug. 27, 1997 could be broken.
Ottawa is forecast to get 15 to 25 millimetres of rain overnight.
Environment Canada warns the rain could cause flash floods and water pooling on roads.
In preparation for a flood, Environment Canada advises people to learn how to shut off their utilities and safeguard heating equipment, along with keeping sandbags and emergency kits.
In the case of a flood, don’t try to walk through the water — even if it looks shallow — and also avoid driving through it.
Precipitation trends vary across the Ottawa-Gatineau region: Ottawa was having a drier year than usual until early summer, while Kingston is still about 200 millimetres below average so far this year.