Happy “Meteorological Summer:” Warming trend; Arctic CO2 reaches 400ppm

MSP Quick look forecast: (Click to enlarge)

Source: Twin Cities NWS

Warmest spring on record? Preliminary numbers suggest spring 2012 may set record

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400 ppm Arctic CO2 levels reach a milestone

"Meteorological Summer" kicks off Friday!

2012 Atlantic Hurricane Season also starts Friday June 1st

70 degrees temps finally return to the 70s this weekend

Increasingly sunny Friday & Saturday

Sunday highest chance of stray showers

Fargo-Moorhead quick look forecast:

Source: Red River Valley NWS Grand Forks

Warmest spring on record in USA?

Here's the data from Capital Climate.

Source: Capital Climate

Welcome to "Meteorological Summer 2012"

If you've ever met one of us you know weather and climate geeks tend to...shall we say... "march to a different drummer?"

Small wonder we would invent our own "seasons" in spite of what the calendar says.

June 1st marks the start of "meteorological summer"...the months June through August.

This one actually makes sense. The solar calendar defines what we know as "astronomical summer" to be from the date of the summer solstice (June 20th this year) to the fall equinox. (September 22nd)

The months of June-August are actually the warmest 3 months of the year, so it makes sense to use them as our definition of "summer" when comparing records and climate.

Here are the monthly average temps for MSP Airport for the milder months.

May 59.1

June 68.8F

July 73.8F

August 71.2F

September 62.0F

The new 30-year MSP climate averages (1981-2010) bumped summer temps at MSP only about .5F, and overall summer temps showed little increase in Minnesota.

The much bigger increase is observed in the winter, where temps run just over 1 degree F above the previous 30 year average.

Source: NOAA

2012 Summer Forecast: Murky crystal ball

A lot of people ask me if there's any way to tell what this summer will be like. I wish I has a clear answer, but summer weather is harder to predict seasonally overall than winter.

Running the numbers on El Nino/La Nina cycles and other longer term "oscillations" seems to yield better forecast "skill" in winter than summer. I'm not sure we understand why that is, but it's fertile ground for future study.

You just can't tell how the summer will be in Minnesota based on previous winters, El Nino cycles etc. with any degree of credibility.

My (unscientific) hunch? We may continue the warmer than average trend of the past 12 months. Why?

-We've already banked 2 90 degree days in May. That's off to a higher than average start.

-We've just logged the 12th straight month of warmer than average temps in Minnesota. 'The trend is your friend."

-Overall climate is shifting and favors increased heat waves and warmer than average episodes.

We average about 14 days at or above 90 degrees at MSP Airport in a summer. My guess is we'll top that again this year...closer to 17 to 20 days of 90 degree heat.

Will we hit 100? We hit 103 last June 7th in the metro... and my hunch is we'll do it again at some point this summer.

Forecast: Back to the 70s

We'll finally return to the 70s this weekend under increasingly sunny skies Friday & Saturday The stubborn cool air mass will give way to more sun and temps should respond to near 70 Friday, and into the 70s this weekend.

It will look and feel a bit more like the first weekend in June.

There si a slight chance of a stray shower, but I really think the highest chance will come Sunday, and especially from the Twin Cities north to Duluth and the North Shore.

Climate Milestone: Arctic CO2 reaches 400 ppm

This news from NOAA is worthy of note. Several sites n the arctic have recorded CO2 concentrations of 400ppm for the first time this spring.

That's a big deal, when you consider that atmospheric CO2 was about 280ppm before the industrial revolution.

The details and an excerpt from the NOAA report.

The concentration of carbon dioxide in the atmosphere of Barrow, Alaska, reached 400 parts per million (ppm) this spring, according to NOAA measurements, the first time a monthly average measurement for the greenhouse gas attained the 400 ppm mark in a remote location.

Carbon dioxide (CO2), emitted by fossil fuel combustion and other human activities, is the most significant greenhouse gas contributing to climate change.

"The northern sites in our monitoring network tell us what is coming soon to the globe as a whole," said Pieter Tans, an atmospheric scientist with NOAA's Earth System Research Laboratory (ESRL) in Boulder, Colo. "We will likely see global average CO2 concentrations reach 400 ppm about 2016."

Carbon dioxide at six other remote northern sites in NOAA's international cooperative air sampling network also reached 400 ppm at least once this spring: at a second site in Alaska and others in Canada, Iceland, Finland, Norway, and an island in the North Pacific.

Measurements at all those remote sites reflect background levels of CO2, influenced by long-term human emissions around the world, but not directly by emissions from a nearby population center. At other more locally influenced sites in NOAA's network, such as Cape May, N.J., upwind cities influence CO2 concentrations, which have exceeded 400 ppm in spring for several years.

"Turning up the levels of greenhouse gases in our atmosphere is like turning up the dial on an electric blanket," said Jim Butler, director of the ESRL Global Monitoring Division. "You know it will keep getting warmer, but you don't know how quickly the temperature will rise, and it can take awhile for the blanket - or the atmosphere - to heat up."

Average global levels of CO2 were 390.4 ppm in 2011, according to NOAA measurements, and will likely reach 400 ppm about 2016. Before the Industrial Revolution of the 1880s, global average CO2 was about 280 ppm.

Seeley: Warm wet May

Finally my MPR colleague and UM climate expert Mark Seeley has details on our warm, and record wet May in his excellent weekley "Weather Talk" post.

Here's a taste.

Topic: Preliminary Climate Summary for May 2012

In the simplest of terms May was warm and wet. Mean temperatures for the month were 2 to 5 degrees warmer than normal, with several days in the 90s F. The extremes for the month were 97 degrees F at Madison on the 18th, and just 24 degrees F at Brimson and Embarrass on the 16th. Minnesota reported the coldest temperature in the nation just twice during the month.

Rainfall during May was abundant and above normal in all areas of the state except the northwest. Many individual climate observers saw their wettest ever May. Some of these included:

Pipestone with 11.06 inches

Windom with 10.83 inches

Lamberton with 9.87 inches

Hawley 6.72 inches

Floodwood 9.14 inches

New Ulm with 12.39 inches

Milaca with 10.46 inches

Sandstone 10.84 inches

Forest Lake with 11.29 inches

Chanhassen with 11.21 inches

Chaska with 10.69 inches

For many observers over half the days of May brought measurable rainfall (16-18 days), and there were many heavy thunderstorms. Overall, taking the average of all rainfall observations in the state it was the 4th wettest May of all time, averaging near 6 inches of rainfall. Only 1938, 1962, and 1908 were wetter on a statewide basis.

Another unusual feature of May was the frequency of strong winds. MSP Airport reported wind gusts over 30 mph on 19 days during the month, and six days with gusts over 40 mph. Some maximum wind gust during the month included: 58 mph at MSP; 62 mph at Alexandria; 69 mph at Rochester; and 74 mph at St Cloud.

PH