Summer solstice Tuesday; Duluth flood 5 years ago today

The Longest Day

Astronomical summer arrives at precisely 11:24 PM CDT Tuesday. It seems like Minnesotans wait all winter for this day. We slog through slush. Brace against bitter breezes. Hope for a glimmer of sunlight. Not this time.

The sun is out in full force over Minnesota Tuesday. We'll soak up virtually every second of the 15 hours and 36 minutes of daylight we've earned this summer solstice. Get. Out. There.

Summer solstice

The sun reaches the furthest point north on its annual trek Tuesday. The sun is as high as it gets, and delivers more solar energy Tuesday than any other day of the year. At 1:14 pm Tuesday (solar noon) the sun will be 68 degrees above the southern horizon.

Earth's axial tilt is the reason we enjoy so much sun this week. This is as good as it gets folks. Soak it up.

Mostly sunny Tuesday

A dry high pressure cell glides over Minnesota Tuesday. With dew points in the upper 40s and low 50s, the atmosphere will be dry. A few faint clouds may zip by, but most of the day we'll see plenty of sunshine. Mostly sunny skies on the summer solstice in Minnesota? Priceless.

Break from June heat

We continue to enjoy free AC this week. June has been running hot, 7.5 degrees warmer than average. We've already logged 5 days at or above 90 degrees at MSP Airport. Temps run about 5 to 10 degrees cooler than average this week.

Next rain Wednesday

A few showers  may ride the northwest flow southeast across Minnesota overnight tonight.Our next significant weathermaker arrives Wednesday. Low pressure pumps more moisture north. Scattered storms increase in coverage Wednesday.

Wednesday severe risk

A few storms may reach severe limits (58 mph winds and or 1" diameter hail) Wednesday.

Duluth flood: 5 years ago

It was 5 years ago today that a massive mega-flood tore up streets and flooded homes in Duluth.

6 to 10-inches of rain fell around Duluth.

The event caused as much as $100-million in damages to infrastructure in Duluth.

A very warm Lake Superior that year combined with extra water vapor from a warmer, wetter atmosphere over Minnesota likely juiced this extreme mega-rain event. The Duluth flood was a 500 to 1,000 year rainfall event for some locations within the flood zone.

I spoke in Grand Marais earlier this month about how Duluth and Minnesota's North Shore contain some unique flood geography.

Mega-Rains increasing

The frequency of so called mega-rain events in Minnesota is increasing as our climate warms. Seven of Minnesota's 15 mega-rain events going back to 1903 have occurred since 2000.

Here's more on Minnesota's mega-rains from the Minnesota DNR Climate Working Group.

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The DNR climate office has assembled a list of so-called "Mega-rain" events that have occurred since statehood. These are events in which six inches of rain covers more than 1000 square miles and the core of the event topped eight inches. Rainfalls of of this magnitude and geographic extent have the potential to become catastrophic. Using newspaper accounts, diaries, and the historical climate record, 15 such events in Minnesota's post-settlement history have been identified. However, our ability to detect these events has improved dramatically since the 1970s.

If we examine the period 1973-2016, Minnesota has seen ten mega-rains. However, of these ten, two were in the 1970s, one was in the 1980s, none were in the 1990s, but the 2000s saw three and the 2010s, still underway, has seen four. Indeed, the frequency of these potentially disastrous events has been increasing sharply, and 2016 became the first year on record with two mega-rains in the state. These trends are consistent with the expectation that Minnesota and the Upper Midwest will receive more precipitation, and more precipitation from large events, in response to increasing global temperatures and increased available moisture for passing storm systems.