Photo: Alertable.ca

This map shows the areas east and northeast of Kamloops placed on a severe thunderstorm watch on Wednesday morning.

UPDATE: 2:51 p.m.

The B.C. River Forecast Centre is upgrading a flood watch to a flood warning in the Blue River area as rain continues to fall in the North Thompson.

The provincial agency made the upgrade at 2:30 p.m. on Wednesday. The warning only applies to Blue River, while the North Thompson, South Thompson and Thompson rivers remain on flood watch.

“A potential long-lasting rain event in the headwaters of the South Thompson, North Thompson and Cariboo Mountains is underway and expected to last into early Thursday,” the River Forecast Centre said in a statement.

“Current rainfall over the past 24 hours has been the heaviest in areas around the Cariboo Mountains and areas around Clearwater and Blue River, with 20 to 50 millimetres of rainfall observed so far, and additional rainfall expected into early Thursday.

“There continues to be risks of significant flooding through the region from this rainfall event.”

A flood warning is issued when river levels have exceeded bankfull or will do so imminently. A flood watch means river levels are rising and will approach or may exceed bankfull.

A flood warning is also in place for the Quesnel River in the Cariboo Mountains.

This story will be updated if more information becomes known.

Are you in Blue River? Send photos or video to [email protected].

ORIGINAL STORY: 9:54 a.m.

A severe thunderstorm watch is in effect for a large swath of B.C. east and northeast of Kamloops, a storm with the potential to dump a large amount of rain on an already swollen river system.

Watches are in effect for the North Thompson, the Shuswap, the north Columbia and the West Columbia — an area that together encompasses Sun Peaks, Salmon Arm, Clearwater, Blue River and Revelstoke.

“Conditions are favourable for the development of severe thunderstorms that may be capable of producing strong wind gusts, large hail and heavy rain,” Environment Canada said in issuing the watch.

Severe thunderstorm watches are issued when conditions are favourable for a storm that could bring with it large hail, damaging winds or torrential rainfall, the agency said.

The City of Kamloops and the B.C. River Forecast Centre have both said any heavy rain in the North Thompson or South Thompson watersheds could mean bad news for flooding in the Kamloops area and beyond on the Thompson River.

Kamloops itself is not included in the severe thunderstorm watch.

If you see the storm happening where you are, send photos or video to [email protected].