Twin Cities, western Wisconsin in severe thunderstorm watch

The strong cap that prevented storms from developing most of the day in Minnesota is eroding with the sunset and intense storms have begun to develop, prompting the National Weather Service to issue a severe thunderstorm watch that includes the entire Twin Cities metro area.

The watch is in effect until 4 a.m. Tuesday, with the weather service saying severe storms could produce "a couple tornadoes" in addition to tennis ball-sized hail and damaging winds up to 75 mph, which are "likely."

The threat in the Twin Cities may only last until about 11 p.m., at which point the severe risk would focus on Wisconsin.

"It may still be another hour or two before storms really get going, in which case the main threat area would be over western WI," the National Weather Service in the Twin Cities said at 9:50 p.m. "However storms could develop rapidly given the high instability, so we still have a threat to watch out for over the metro for the next hour or so."

The HRRR model is suggesting that the northern half of the watch box will bear the brunt of the storms, with this scenario keeping the Twin Cities mostly out of the woods.

The NAM 3km model shows more robust development that stretches into southeastern Minnesota.