Rainy Sunday soaker, longer daylight in 10 days

Waiting for winter

This may end up as one of the shortest winters in memory.

Minnesotans and the nation are still waiting for the season formerly known as winter. The warmest fall on record for the U.S.? Throw in an eerily mild December so far, and this has been the warmest fall and early winter season on record in Minnesota.

Green grass. Open water. Golfers two weeks before Christmas. Soil temperatures still way above freezing.

Now we watch as the next inbound storm system dumps more December rain on the Twin Cities Sunday, and a few paltry inches of wet snow up north.

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It's not unusual to have a strong storm this time of year winding up on the weekend weather maps below. What is odd is the sheer magnitude of warmth being injected into the system. Mostly rain in mid-December is not the norm in Minnesota. Sunday's rain-snow line stretches between Willmar and Duluth. To the east of that line? More December rain showers.

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NOAA

Wetter pattern

This system and the one next week will lay down some heavy rainfall totals from southeast Minnesota into the Mississippi Valley and southern Plains.

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NOAA

Snow up north

The system stays cold enough for snow in the far north this weekend. Expect several inches of heavy wet snow from International Falls to the Iron Range cities, through Ely and into the BWCA. Mixed rain at times along the North Shore will reduce totals.

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Frost free soils

If you've delayed pushing those snow stakes into the grass by the driveway you'll have no problem this weekend. Soils across southern Minnesota are still largely frost free. Here's the soil temperature data over sod from the St. Paul Campus at the University of Minnesota. 41 degrees on December 10th?

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University of Minnesota

The average date of the initial soil freeze in the Twin Cities? December 8th.

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Minnesota Climate Working Group

5 years since Domebuster: 5th biggest snowstorm in metro history.

What a difference 5 years ago this week. Here's my forecast and review of the infamous "Domebuster."

Better snow chances next week?

For the Twin Cities, snow chances still look more favorable next week.

Here's the European Model (ECMWF) map for next Wednesday at 6 a.m. Low pressure tracks across Minnesota, and it should be cold enough for snow. Questions still revolve around how much snow this system will produce, but it should be enough to lay down a white coating in many areas that are currently green.

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Montreal Weather Centre

Here's a closer breakdown of the next week according to the European model.

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Weatherspark -Euro data

The longer range data suggest colder temps late next week, followed by another warmup next weekend. This fits with my previous forecasts suggesting difficulty sustaining any prolonged cold-air outbreaks this winter.

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NOAA via IPS Meteostar

Minnesota: Warmest on record since Sept. 1

Our unseasonably mild December so far has pushed us over the top. This is now the warmest post-Sept. 1 period on record in Minnesota. Mark Seeley has more in this week's Weather Talk.

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Topic: Abnormally warm temperatures persist

September of 2015 set a record as warmest in Minnesota history on a statewide basis.  It also marked a turning point in the temperature trend for the year as a whole. For the first 8 months of the year (January-August) Minnesota was mostly recording a relatively even mixture of warmer and colder than normal daily temperatures.  However starting in September and continuing into the first 10 days of December over 80 percent of all days have produced warmer than normal temperatures.  The 3-month period of September through November was the 2nd warmest in Minnesota history on a statewide basis, trailing only 1963 by 0.2°F.  Further if you add in the first 10 days of December, the stretch of days from September 1, 2015 to December 10th is the warmest in state history, a remarkable run  of warmth.

So far this month, 21 daily maximum temperature records have been set within the Minnesota climate observer network, including a reading of 50°F at Grand Portage (Cook County) on December 7th.  In addition 36 new daily warm minimum temperature records have been set so far this month, including a nighttime minimum of 36°F at International Falls on December 5th, a reading that is 16°F above the normal maximum temperature for the date.  In addition MSP set new highest dew point records on December 9 (38°F) and December 10 (40°F) this week.

Though not record-setting all of these climate observers reported a daytime high of 50°F or greater on December 10th (well over 20°F above normal):  Pipestone, Montevideo, Canby, Wheaton, Appleton, Granite Falls, Jackson, Redwood Falls, Windom, St James, New Ulm, Fairmont, Olivia, and Tracy. 

So far temperatures for the month of December are averaging 8 to 16 degrees F warmer than normal for most communities across the state.  The National Weather Service expects some moderation in temperatures for the second half of December, but generally the trend of above normal values is expected to continue. 

3rd Climate Minnesota Adaptation Conference In January

I attended the first two, which were valuable discussions of where we are as our Minnesota climate shifts. The details are from Dr. Seeley.

Announcement:  Third Annual Climate Adaptation Conference, January 28, 2016

Registration is now open for the 3rd Annual Minnesota Climate Adaptation Conference on January 28, 2016 at the Hilton DoubleTree in north Minneapolis.  This conference is designed for local officials, planners, engineers, natural resource practitioners and others who want to learn more about adaptation strategies that have worked or are being tested in various sectors, tribal communities, energy, local foods, emergency management, communication and water resources.  At the conference we will also hear from several major corporations about how they are addressing climate adaptation and listen to a mayor’s panel at lunch where they will discuss city approaches to climate adaptation. 

For the second year, Climate Adaptation Awards will be presented to recognize achievements in leadership, education, research, policies, or practices that improve resilience and advance climate adaptation in Minnesota.

Later sunsets now, gaining daylight in about 10 days

This weekend marks the time when sunsets start getting ever so slightly later in Minnesota. This happens even before the solstice on Dec. 21.

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NOAA

Here's a good explanation as to why from sunrisesunet.com.

December Solstice (Winter Solstice) is on Monday, December 21, 2015 at 10:49 PM in Minneapolis. This day is 6 hours, 51 minutes shorter than on June Solstice. In most locations north of Equator, the shortest day of the year is around this date.

Earliest sunset is on December 9 or December 10.

Why isn't the Year's Earliest Sunset on the Winter Solstice?                                                                                                                   

The Winter Solstice usually occurs around December 21 in the Northern Hemisphere and June 21 in the Southern Hemisphere. Many believe that the year’s latest sunrise and earliest sunset also happen on this day. This is not the case.

If you look at the sunrise and sunset timings for any city in the Northern Hemisphere around the December Solstice, you will notice that the earliest sunset occurs a few days before the Solstice. Similarly, the latest sunrise happens a few days after the solstice.

What explains this curious occurance? Why doesn't the shortest day of the year also have the latest sunrise and the earliest sunset of the year?

Two different factors combine to cause this interesting phenomenon:

  • the equation of time

  • a location's latitude.

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sunrisesunset.com

The Equation of Time

Very simply, the equation of time is the difference between time that is measured using a sundial (true or apparent solar time) and time that is measured using a watch or a clock (mean solar time).

Most clocks work on the idea that a day - the time between one noon to the next - is exactly 24 hours.

Scientifically, however, a day is defined as the duration between 2 solar noons. A solar noon is the time of the day when the Sun is at the highest point in the sky, and a solar day is the duration between two solar noons.

A solar day is not exactly 24 hours long. Its length varies throughout the year. In fact, the solar day is longer than 24 hours around the summer and winter solstices and is shorter than 24 hours around the spring and fall (autumn) equinox. This means that the length of the solar day does not always match up to the length of a day as measured by a clock. This is because of two reasons:

  • Elliptical shape of Earth's path around the Sun The shape of the Earth’s orbit around the Sun is closer to an oval than a perfect circle. The technical term for its shape is an ellipse. The Sun is not situated in the center of this elliptical orbit, but closer to one side than the other. Because of this, the Earth comes closer to the Sun (the Perihelion) during one part of its orbit than the other (the Aphelion). When do the Earth's Perihelion and Aphelion occur? The speed at which the Earth moves around the Sun varies throughout the year. When it is closest to the Sun, the Earth travels about 13,500 miles (21,726 kms) more each day than when it is away from the Sun on its orbit.

  • The Earth's axial tilt In addition to moving around the Sun, the Earth also rotates on its own axis. The axis is an imaginary line that passes through the North and the South pole. It is tilted to about 23.5° in relation to the Earth's orbital plane around the Sun (the ecliptic). This tilt is known as the Earth's obliquity, and is responsible for seasons.

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NOAA

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