Warm weather this week, but dwindling daylight

Happy autumnal equinox to all of our friends in the Northern Hemisphere!

This annual celestial milestone will occur at 9:29 p.m. this evening when the sun appears directly over the equator at a location just north of New Guinea. At that time the sun will be lighting the sunny side of Earth from the North Pole to the South Pole.

This diagram from the National Oceanic and Atmospheric Administration shows how it all works relative to the 23.5 degree tilt of Earth's axis that we learned about in science class.

Sept 22 - equinox
This diagram is not to scale as distances and the size of the sun have been compressed.

Our length of daylight peaked back in June around the summer solstice. We have been losing daylight and gaining darkness since then, and the pace of day-shortening has increased until the equinox.

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You probably have noticed how much earlier in the evening the sun is setting across Minnesota -- just 7:10 p.m. this evening in the Twin Cities, 7:16 p.m. in Walker and 7:04 p.m. in Winona. The good news is that the pace of day-shortening will slacken as we head toward the winter solstice in December.

Satellite photos have been showing an abundance of clear skies over Minnesota today.

Sept 22 - vis sat
Visible satellite Monday afternoon. Source:NOAA

Along with the clear skies, the dry dew points have contributed to excellent visibility and sharp colors in the vistas of leaves changing color, mainly up north.

U.S.D.A. Forest Service Webcam Image
Shot from web cam in the Boundary Waters Monday morning. Source: U.S. Forest Service

Unfortunately, when the sun sets directly in the west this evening the timing will be a bit too late to give us a view of the 2-percent waning crescent moon as it will set almost an hour before the sun. These lovely, skinny crescent moons are a treat reserved for later in the season when they approach the western horizon during the dark of early evening.

Weather this week should be warm and mostly dry with temperatures running significantly above normal statewide, more like early September than the last full week of the month. By Thursday through Sunday, I expect much of the state to see highs reach well into the 70s. In fact, thermometers across much of southern, central and western Minnesota from the Twin Cities to Mankato and west to Willmar, Alexandria and Ortonville should read around 80 on Friday and Saturday afternoons.

Some showers are likely in southwestern Minnesota on Tuesday and isolated showers around the state Tuesday night. The best chance of a stray shower or two on Wednesday will be north of Duluth. No severe weather is expected this week.

Here is how the Duluth National Weather Service Office summarized the upcoming days for much of northern Minnesota.

Sept 22 - NWS Duluth wx story

Opportunities for outdoor activities will abound this week and then continue for the weekend.