A tornado warning for Woodstock and Carleton County has been downgraded to a severe thunderstorm warning and rainfall warning for Wednesday night.

Environment Canada says a severe thunderstorm east of Woodstock is moving east-southward, as of about 6:30 p.m. AT.

Another severe thunderstorm in Maine is expected to track just south of Woodstock within a half hour, the weather agency states.

nb-tornado-warning-map

A tornado warning has been issued for Woodstock and Carleton County. (Twitter)

Severe thunderstorm warnings are also in place for Fredericton and Southern York County, as well as Stanley, Doaktown and the Blackville area.

Area residents are urged to take cover in a sturdy building, away from windows if threatening weather approaches.

"Strong wind gusts with large hail can damage property, break windows, dent vehicles and cause serious injury. Heavy downpours can cause flash floods," the warning states.

"Avoid driving through water on roads. Even shallow fast moving water across a road can sweep a vehicle away."

Most of the province is under a severe thunderstorm watch, with the exception of Saint John and County, Grand Manan and Coastal Charlotte County.

There are also rainfall warnings in Campbellton and Restigouche County, Edmundston and Madawaska County, Grand Falls and Victoria County, Mounty Carleton and the Renous Highway, Stanley, Doaktown and the Blackville area.

Some regions could see up to 60 millimetres of rainfall on Thursday, according to alerts.

Environment Canada had issued a tornado warning for Woodstock and Carleton County shortly before 6 p.m.

"This is a dangerous and life-threatening situation," the weather agency had stated.

"A severe thunderstorm, possibly producing a tornado, as indicated by doppler radar, will cross the border very shortly."

EMO issues advisory

nb-rain-thunder-warning-map

Some parts of the upper Saint John River Valley could see up to 90 millimetres of rain by Sunday. (Twitter)

The Department of Public Safety's Emergency Measures Organization issued an advisory on Wednesday for people living in the Perth-Andover, Grand Falls and Florenceville areas, warning about heavy rainfall and severe thunderstorms in the forecast over the next few days.

There is a threat of localized flooding, particularly in areas that have flooded in the past, the organization said.

Residents are advised to stock up on enough food, water, medication, batteries and other essentials to last 72 hours.

Motorists are being urged to stay off the roads during severe weather if possible, or adjust their driving to road conditions.

This weather is not associated with Tropical Storm Gabrielle, which is currently northwest of Bermuda and expected to hit eastern Nova Scotia, Cape Breton and Newfoundland by Friday.