Saturday morning thunder; steamy weekend ahead

Hour-by-hour

We call it nowcasting in meteorology. That's when weather patterns are so diffuse that small-scale features can drive thunderstorm waves on a moments notice. In our current weather pattern, there are no big bad obvious fronts to focus storm waves. Forecasting the timing of summer thunderstorms is often an hour-by-hour endeavor. It's a combination of good high-resolution models and forecaster skill and experience.

Wee hour storms?

Our high degree of difficulty forecast looks interesting as we move into Saturday morning. Some of the latest model runs depict a developing thunderstorms cluster near Lake Mille Lacs around midnight. The weak northerly steering currents then push this potentially severe squall line through St. Cloud and into the Twin Cities area between 2 and 4 am Saturday. The storms could linger through about 7 or 8 am before dissipating.

NOAA's NAM 3 km model paints that scenario.

Severe risk

Thr risk is there for large hail and damaging winds with the storms early Saturday morning. NOAA's Storm Prediction Center paints a slight risk across most of Minnesota overnight through Saturday.

Heavy rainfall

Slow moving storms could dump torrential rains. Multi-inch rainfall totals are possible over much of Minnesota into Wisconsin.

Hot steamy weekend

The best chance for storms in southern Minnesota is early Saturday morning and late Sunday. The northern half of Minnesota may see more frequent storm action Saturday and Sunday. Locally heavy rainfall is likely up north this weekend.

Relief arrives next week

A fresh Canadian air mass shoves the heat and humidity south next week. Temperatures relax back into the 80s, and dew points fall into the comfortable 50s once again.

Stay cool and keep the weather radio handy this weekend.