Fickle Saturday; waves of Canadian cooldown on their way

Temperatures across Minnesota were quite variable Saturday afternoon. The Twin Cities sat beneath a dark blanket of low clouds that held readings below the forecast highs of mid 70s. Where the sun broke through the clouds, such as in Jackson in southwestern Minnesota, Madison in the west central part of the state and Hallock in the northwest, afternoon warmth flirted with 80 degrees.

Many of the coolest locations have been where rain has been falling and saw highs held down to the upper 50s to low 60s. As of approximately 5:00 p.m. numerous areas of rain stretched from west central Minnesota to the Arrowhead and from parts of the Twin Cities area to northwestern and north central Wisconsin. Thunderstorms have been developing rapidly across the northern Twin Cities area.

Shortly after the above radar image was taken, the National Weather Service issued a severe thunderstorm warning for southeastern Chisago County of Minnesota and Baron and Polk Counties of western Wisconsin. Radar indicated that half dollar size hail was possible as this storm raced toward Frederic and Luck, Wisconsin. The estimated maximum size of the hail was decreased to quarter size as the storm moved out of Minnesota and into Wisconsin.

Strong and severe storms likely for northern Wisconsin

A low pressure center and its attached warm front are setting the stage for increased thunderstorm development in northern Wisconsin. Strong thunderstorms will continue to build in that area Saturday evening. More storms could easily become severe with the greatest threat being damaging hail. The Storm Prediction Center has issued a Slight Risk for severe weather across much of northern Wisconsin and Upper Michigan for Saturday evening and into Saturday night.

Cooldown coming to your backyard

A parade of Canadian cold fronts swinging around cyclonic flow will bring an attention-getting cooldown this coming week to remind us that October will be arriving on Thursday.

Sunday will get things underway with high temperatures about normal for this time of the year and a gusty westerly breeze.  High temperatures should range from the upper 50s in the north to the upper 60s farther south. While a gusty west breeze will have a cooling effect, those temperatures will be about normal for late September.

Scattered showers will dampen northwestern Minnesota Sunday morning before tracking southeast toward the Twin Cities area in the afternoon.

Reinforcing chilly air means progressively cooler temperatures through the workweek. The coldest period will probably be Thursday night and on Friday. High temperatures on Friday are likely to reach just the low 50s in the Twin Cities area and even cooler farther north.

Scattered showers, most with little rainfall, are likely to break out on just about any day this week, usually with the aid of the heating of the day.

Milder next weekend and beyond

Forecast models are calling for a return to more-normal temperatures next weekend and likely for a few days beyond.