Tornadoes, debris ball, major heat wave next week?

This summer is turning out to be a wild one in Minnesota. Monday's intense storm dropped multiple tornadoes and flash floods.

The big picture climate perspective on Monday's storms? A warmer wetter atmosphere probably contributed to the excessive rainfall totals in central Minnesota.

Dew points in the 70s to as high as 82 degrees in Sioux Falls, S.D., ensured a ripe air mass capable of severe weather and flooding rains. Symptoms of a warmer climate in Minnesota continue to unfold, as more of our weather is colored by climate changes.

Multiple tornadoes in central Minnesota

Several tornadoes skipped across central Minnesota Monday evening.

https://www.youtube.com/watch?v=5M1vZwEsxtg

I live-tracked the tornadoes on MPR News last night as multiple touchdown reports came in.  The same rotating tornadic supercell likely produced all four twisters along a Litchfield-St. Cloud line.

I'm thankful St. Cloud got lucky Monday night. The tornadic storm appears to have lifted just before entering the core of the city. Yes, it could have been so much worse.

The Twin Cities National Weather Service is in the field today conducting damage surveys.

https://twitter.com/NWSTwinCities/status/752872518365642752

The EF-2 Watkins tornado packed 125 mph winds along a 200 yard wide damage swath as it tore through Watkins southwest of St. Cloud. The damage "debris ball" was clearly visible on Doppler radar Correlation Coefficient mode.

The Litchfield tornado packed 115 mph winds and is also rated EF-2 by the Twin Cities NWS.

The Twin Cities NWS will post the storm survey results here as they are completed.

Anatomy of an outbreak

Needless to say, conditions were ripe for tornadoes across central Minnesota last night. Meteorologists get our antennae up when we see a warm front with turning low level winds draped across the forecast region in summer.

NOAA's significant tornado parameter factors in updraft potential and wind shear. Bull's-eye for central Minnesota last night.

NOAA's Storm Prediction Center tallied seven preliminary tornado reports last night. Some of these were multiple sightings of the same tornado.

Flooding up north

The magnitude of persistent heavy rainfall in central Minnesota was impressive. Some 8- to  10-inch rainfall totals were observed across the region.

The storm total rainfall mode from the Duluth NWS Doppler radar is painted with rarely used colors.

Rivers continued rising across central Minnesota and northwest Wisconsin Tuesday.

Numerous flood reports rolled into the Duluth NWS. Water continues to flow in unusual places.

The worst flood damage is in northwest Wisconsin where many roads are washed out. This is what two to three months of rain in a few hours will do.

The Snake River near Mora, Minn., continues to rise into flood territory.

Here's more on the Northland storms from the Duluth NWS.

Multiple rounds of showers and thunderstorms - some storms strong to severe - impacted much of east-central to northeast Minnesota into northwest Wisconsin Monday July 11, 2016, with the worst of the heavy rain and flash flooding occurring in the evening hours.

This resulted in significant flooding across parts of the region and many road closures, including the closure of Interstate 35 for a period of time.

Also, a bow echo type storm moved across northern Iron County, WI and caused tremendous amounts of damage at Saxon Harbor, WI. Numerous vessels were affected by the severe downburst winds. There were 23 beached vessels, 6 vessles became adrift and some were overturned. There was also substantial wind damage at the campground.

Forecast: Drier and milder

We enjoy a respite from the storms in the south as the slow moving system edges eastward. The next cool front brings more rain chances to northern Minnesota.

The Twin Cities forecast reads comfortably pleasant through Friday with an outside shot at a passing shower.

Summer's biggest heat wave next week?

The maps show a surge of heat and moisture north into Minnesota next week as the upper air flow buckles. A "heat pump" high-pressure cell builds aloft over the Midwest next week.

Several days of high dew points in the 70s and high temperatures in the 90s are possible if this pattern verifies. The heat wave with significantly above average temperatures is likely to cover most of the central and eastern U.S. next week.

The European Centre for Medium-Range Weather Forecasts model is cranking out highs as hot as 97 degrees for the Twin Cities by next Thursday.

NOAA's Global Forecast System suggests several days in the 90s in the Twin Cities, with temps approaching 100 degrees in southwest Minnesota. The core of 100+ degree heat sets up over South Dakota by next Tuesday.

Temps approaching 110 degrees in South Dakota next week? This could evolve into a serious heat wave.

Stay tuned.