“6 week summer” of 2013? Even colder late next week; Is “Arctic Amplification” to blame?

Calendar Counting

Summer in Minnesota can be like a game of Whac-A-Mole. We take the warm days and weeks, and try and swat away any cool days as they pop up.

We  jam activity filled weekends to the lake, the concerts, festivals and the local "crazy days." It's almost nice when fall finally arrives so we can clear our overbooked calendars for a while.

Realistically, "summer" in Minnesota began on June 16th this year when the mercury hit 86 degrees n the metro. It may have "ended" when we hit 83 degrees on July 25. That's the last day with an 80+ degree in the metro high before we plunged into our current state of weather affairs -- a string of days in the 70s and even October-like 60s.

6 weeks of summer in Minnesota this year?

That would be hard to take for even the most hardy Minnesotans after the non spring of 2013. I'm not saying we're done with 80s this year. But they look unlikely for the next 10 days or so. The maps do look potentially warmer by mid-August, and another string of 80s, even a 90 degree day or two is not out of the question. The State Fair still brings us a shot of 90 degree heat right?

Last fall and early winter, some bold predictions blared headlines predicting "drought" as the big headline of 2013. Ooops. Minnesota farmers struggled to get crops into soggy fields this spring. My Boston Whaler is practically underwater on my ramp this summer on brimful Lake Minnetonka which is up almost 3 feet. It's not a good bet to go out on a limb in Minnesota predicting the next big weather story. Minnesota weather has a way of surprising you.

Many of you I talk to hope the surprise this year includes a late summer run of warmth that lingers well into fall.

In the meantime we prepare for another shot of September...and even October this weekend and next week.

Stay tuned.

Scattered showers return tonight and tomorrow

This morning's showers were courtesy of a weak upper wave of low pressure that meteorologists call "short waves." Rather than big dramatic atmospheric waves that spin up huge storms, short waves trigger smaller, shorter-lived batches or rain and thunder in summer.

The next wave and cold front sails in tonight into Wednesday and will trigger another round of showers and a few T-Storms. Rainfall totals look generally light with most areas under .25" this week.

September rerun this weekend?

Behind the front, the next wave of Canadian air will be very pleasant but unseasonable cool later this week and this weekend. Temps will run about -10 vs. average this weekend. That means highs in the low-mid 70s in the metro and 60s to near 70 up north.

October Preview #2 next week?

last weekend may have been the appetizer. The main course for our next October preview comes next week as an unusual August "Polar Vortex" spins into Minnesota from northern Canada.

If this unseasonably cold upper low verifies next week, temps could run as much as 20 degrees colder than average by late next week in Minnesota. That could mean more widespread 30s...and frost up north and highs again in the 60s in the metro and south.

There is hope for warmer weather to return in mid-August. Temps will likely return to the 80s again...and I wouldn't rule out 90s by State Fair time just yet. But the window for an extended run of hot weather is closing fast.

Short Summer of 2013? Is Arctic Amplification to blame?

People are asking em what's causing our abbreviated summer this year. The leading theory among the climate scientist I talk to and read? Arctic Amplification and an unusually "loopy" or "drunken" jet stream pattern over North America.

It goes like this.

-A warmer Arctic actually decreases the temperature contrast between the poles and equator.

-The jet stream slows down, and becomes more "loopy" (high amplification pattern)

-Dips in the jet stream...and "cut-off lows" slide over the Upper Midwest bringing a cooler northwest flow of Canadian air

-The Arctic warms up, and colder air is displaced south to places like Minnesota

Minnesotans shiver; Alaskans hit the beach

While beaches empty and furnaces kick in in Minnesota, "Arctic amplification" means residents of Alaska are enjoying one of the warmest summers on record.

Here are some details on a balmy summer from the Alaska NWS.

Yesterday the Fairbanks Airport climbed to 81 degrees which marked the 27th day the temperatures have reached 80 degrees or warmer. Today is also on track for temperatures to reach above 80 degrees, with the current temperature of 85 as of 300 PM AKDT. This is this 28th day this summer the temperature has reached 80 degrees or warmer at the airport. The summer of 2013 has tied the second place for the number of days when the temperature has reached or exceeded 80 degrees since reliable temperature records began in 1930. The summer of 1990 also had 28 days.

At 300 PM AKDT, the Fairbanks Airport reached 85 degrees which also sets a new record 12 days this summer for the most number of days that the temperature was 85 degrees or warmer since 1930. The record was recently broken on July 14, 2013 when the Fairbanks Airport reached 87 degrees. The average number of days Fairbanks reaches 85 degrees or warmer is 3

There is a potential this week to tie or beat the record which is 30 days set in the summer of 2004. The average number of days Fairbanks reaches 80 degrees or warmer is 11.

The 2nd warmest summer on record in Fairbanks, Alaska? "Arctic Amplification" may be the reason.

Here are some more details from NASA's Earth Observatory on the science behind Arctic Amplification.

As far back as 1896, the Swedish scientist Svante Arrhenius hypothesized that changes in the concentration of carbon dioxide in Earth’s atmosphere could alter surface temperatures. He also suggested that changes would be especially large at high latitudes.

Arrehenius didn’t get every detail right, but his argument has proven to be pretty sound. Since the mid-20th Century, average global temperatures have warmed about 0.6°C (1.1°F), but the warming has not occurred equally everywhere. Temperatures have increased about twice as fast in the Arctic as in the mid-latitudes, a phenomenon known as “Arctic amplification.”

The map above shows global temperature anomalies for 2000 to 2009. It does not depict absolute temperature, but rather how much warmer or colder a region is compared to the norm for that region from 1951 to 1980. Global temperatures from 2000–2009 were on average about 0.6°C higher than they were from 1951–1980. The Arctic, however, was about 2°C warmer.

Why are temperatures warming faster in the Arctic than the rest of the world? The loss of sea ice is one of the most cited reasons. When bright and reflective ice melts, it gives way to a darker ocean; this amplifies the warming trend because the ocean surface absorbs more heat from the Sun than the surface of snow and ice. In more technical terms, losing sea ice reduces Earth’s albedo: the lower the albedo, the more a surface absorbs heat from sunlight rather than reflecting it back to space.