Region braces for powerful thunderstorms that could produce powerful tornadoes, along with damaging hail and winds.

The US National Weather Service (NWS) has warned that severe thunderstorms forming across the country’s midwestern region could produce powerful tornadoes, along with large hail and damaging winds.

The afternoon and evening hours on Saturday are expected to see the peak of the storms, with tornadoes developing.

With the worst of the storms expected after dark, the tornado outbreak is considered especially dangerous.

The weather system bringing the severe thunderstorms began with snow across the Rocky Mountains on Thursday, moving through the Central Plains during Friday.

Golf ball-sized hail fell over counties in Oklahoma and southern Missouri, damaging cars. The NWS’s Storm Prediction Center reported 87 preliminary hail reports.

As the storms continue to move east on Saturday towards the Midwest, winds will increase and are forecast to reach damaging speeds up to 110 kilometres per hour (70 miles per hour), leading to uprooted trees and power outages.

Flash flooding is also possible as heavy rain will accompany the storms.

Large, highly populated cities such as Chicago, St Louis and Little Rock are amongst the areas at high risk of storm and tornado damage. The NWS is also predicting baseball-sized hail.

By Sunday, the severe storm threat will ease for the Midwest.

Storm warnings will then be in place for the southern states of Alabama and Georgia, where areas could see isolated, severe storms developing throughout the day.