Typical Peak Color
According to the MN DNR, here is the typical peak of fall color across state. Note that fall colors typically peak across the international border mid to late September, which is only a few weeks away. Meanwhile, peak color in the Twin Cities metro generally isn't until around MEA Weekend.
What Causes Fall Color?
The following information is from the MN DNR via Joe Zeleznik, Extension Forester, North Dakota State University. 2007. Fall Colors of North Dakota. Pages 15-16 in North Dakota Climate Bulletin.
"What Causes Fall Color? The Chemicals! Four main groups of biochemicals are responsible for the various yellows, oranges, reds and browns that we see in the fall:"
"Each has its own color and chemistry. As the amount of these chemicals vary, they will cause subtle variations in color from one leaf to the next, or even from tree to tree. "
"The green color that we see on most plant leaves throughout the spring and summer is caused by a pigment called chlorophyll. Chlorophyll is one of several pigments that gather energy from sunlight in the process of photosynthesis. Chlorophyll absorbs both the blue and the red wavelengths from sunlight, and reflects the green wavelengths. Nitrogen is one of the main components of chlorophyll. As our days shorten and temperatures get cooler, chlorophyll is broken down faster than it's produced. The majority of the nitrogen migrates back to the twigs, where it is stored for next year's new growth. As chlorophyll breaks down, the carotenoids are revealed."
"Many of the yellows and oranges we see in nature are the result of carotenoid compounds. They are what make carrots orange! Carotenoids play a minor role in photosynthesis—they are present throughout the growing season, but are only revealed when chlorophyll breaks down. You are more likely to see brilliant colors when the fall weather has warm, sunny days with cool nights between 32° and 45 °F. Look at a leaf that has been grown in the shade, and you may notice it is a duller color than leaves that grew in the full sun, even on the same plant."
"The reds and purples you see in the fall are caused by anthocyanins, which are what you get when sugars combine with compounds called anthocyanidins. Many things affect the exact color produced by anthocyanins, including the pH (acidity or alkalinity) of the cell sap in the leaves. With an acid pH, anthocyanins are often red; with a more alkaline pH they turn purple-to-blue. Because anthocyanins need sugar for their creation, weather that favors photosynthesis (sugar production) is essential. Bright, sunny fall days produce the best colors. Very little photosynthesis occurs on cloudy days, and rain can actually leach the anthocyanins and carotenoids out from the leaves. Different combinations of anthocyanins and carotenoids can result in there being yellow, orange and red leaves all on the same tree at the same time. The exact color a tree produces will vary from year to year. Some people believe they can force a more brilliant red color by adding acid-forming fertilizers to the tree, especially aluminum sulfate. This method may sound like it should work, but there is no scientific evidence to support it."
"In many forests, oak trees don't add much to the collage of fall colors. They often just turn brown, thanks to a group of compounds called tannins. Tannins are revealed when both chlorophyll and carotenoids break down in the leaves. Some oaks do produce a light red or pink color in the fall, but our native bur oak does not."
(Image below courtesy MNDNR via Park Staff at Mille Lacs Kathio State Park)
How Does Weather Affect Fall Color?
The following information is from the MN DNR via Val Cervenka, DNR Forest Health Specialist.
"Here's why fall colors vary from year to year and place to place:
Weather is most critical in determining the colors displayed each fall.
Colors are best when high quality foliage - a product of a warm, moist summer is exposed to sunny, cool fall days.
Light frosts may also help, but hard freezes can ruin the display.
Physiological stresses placed on trees can impact fall colors.
Cool, we summers can cause premature displays of color.
A mild summer drought may actually increase the display, but severe drought usually dulls colors noticeably. In some cases, foliage may die early and turn straw-colored due to a lack of water.
The slightest changes in weather in September - too warm, too cold, too wet, too dry - can slow color change or cause trees to drop leaves before they change color.
Becuase it is too dry to produce the vibrant reds, yellows, and orages, a severe summer drought will create a landscape filled with the subtler colors of tans, bronzes and auburns."
(Image courtesy MN DNR via Park Naturalist at Fort Snelling State Park)
Minnesota Crop Update
The information below comes from the MN USDA...
Rainfall Potential Through PM Monday
Rainfall potential PM Sunday / AM Monday looks fairly impressive with several locations possibly getting up to an inch of rain! After the rain pushes east AM Monday, it looks like the much of the week ahead will be dry once again.
Simulated Radar PM Sunday
Here's the simulated radar from 5PM to 11PM Sunday, which shows a line of strong to severe storms developing in western MN and then rumbling east through the night. Again, some of the storms could produce damaging winds with locally heavy rainfall.
Sunday Weather Outlook for Minneapolis
Sunday Meteograms for Minneapolis
Sunday morning will be a bit cool, but pretty mild for mid October. Keep in mind that the average low temperature in the Twin Cities is in the lower 40s. Temps will quickly warm through the 50s in the morning and top out around 70F throughout the afternoon. Southeasterly winds will be quite breezy with wind gusts approaching 30mph during the afternoon.
Sunday Weather Outlook
Here's a look at high temps around the region and note that many locations will be nearly +5F to +15F above average, while a few locations in Southwestern MN will be nearly +20F above average! Much of southern MN will warm into the 70s with lower 80s possible in the southwestern part of the state. Strong south to southeasterly winds will also develop throughout much of the afternoon. Wind gusts could approach and exceed 30mph for much of the state. There could even be a few 40mph wind gusts over southwestern MN. With that said, elevated fire weather conditions will be in place south and west of the I-94 corridor.
Extended Temperature Outlook For Minneapolis
Sunday could be one of last really mild days of 2020... Take a look at the temperatur tumble into the week ahead. Note that our average high in the Twin Cities after October 13th (Tuesday) drops below 60F. The 2nd half of the week looks even cooler with highs falling into the lower 50s. On Saturday, we might not even make it out of the 40s... Sweater weather returns in a few days.
Extended Temperature Outlook For Minneapolis
As we look deeper into October, you can see that temps look even cooler with highs only warming into the 40s, several days during the 2nd half of the month. Note that average highs in the Twin Cities don't drop into the 40s until November. With that said, will definitely be running below average in the temp department during the 2nd half of the map if the current forecast holds. We could also be looking at several mornings with frost and freeze concerns.
Average First Frost Minneapolis
The average first frost in the Twin Cities is typically around mid October. Note that we had our first official frost in the Metro on the morning of October 4th. The temperature at the KMSP Airport dropped to 32F on Sunday the 4th, which is about a week and a half earlier than normal (October 13th).
Average First 1" Snowfall at MSP
The first 1" of snow typically happens around the 3rd or 4th week is November. The lastest first 1" of snow didn't fall in the metro until January 1st, back in 2005!
Strong Storms Precede Welcome Soaking Tonight
By Paul Douglas
"Lightning never strikes the same place twice!" I beg to differ. High-rise buildings like Chicago's Willis Tower and New York's Freedom Tower are routinely struck dozens of times every year.
Hurricanes can strike the same communities back to back, although it is rare. Hurricane Delta just flooded Louisiana, 43 days after Hurricane Laura hit the same area.
Severe storms in October are rare, but not unprecedented here. Minnesota's latest tornado on record was November 16, 1931, near Maple Plain.
I don't expect tornadoes but straight-line wind damage is possible from strong to severe storms later today. Models are more impressive for rainfall amounts tonight; an inch or more for some lucky lawns and fields. Stating the obvious: we need the rain.
Another shower Wednesday marks the leading edge of a colder cold front. Highs hold in the 40s Friday and ECMWF hints at 30s by early next week.
That said, yesterday's Crayola colors and flawless sky were another poignant reminder why we live he here. Wow.
SUNDAY: PM severe storm risk. Winds: SE 15-30. High: 71.
SUNDAY NIGHT: Showers and storms likely after 8pm. Some could be strong/severe. Winds: SE 15-30, turning W after midnight. Low: 51.
MONDAY: Wet start, then rapid clearing. Winds: W 10-20. High: 65.
TUESDAY: Peeks of sun. Stiff breeze. Winds: NW 10-20. Wake-up: 50. High: 63.
WEDNESDAY: Unsettled with a passing shower. Winds: NW 15-25. Wake-up: 49. High: 62.
THURSDAY: Mostly cloudy and chilly. Winds: NW 10-20. Wake-up: 40. High: 52.
FRIDAY: Passing sprinkle or flurry? Raw. Winds: NW 10-20. Wake-up: 34. High: 48.
SATURDAY: Mostly cloudy. Trending milder. Winds: S 10-20. Wake-up: 38. High: 60.
This Day in Weather History
1909: A snowstorm hits the state, along with temperatures dropping to 7 degrees over northern MN.
Average High/Low for Minneapolis
Average High: 61F (Record: 85F set in 2015)
Average Low: 41F (Record: 22F set in 1876)
Record Rainfall: 1.36" set in 1881
Record Snowfall: 0.5" set in 1977
Sunrise/Sunset Times for Minneapolis
Hours of Daylight: ~11 hours & 10 minutes
Daylight LOST since yesterday: ~ 3 minutes & 3 seconds
Daylight LOST since Summer Solstice (June 20th): ~ 4 hour & 27 minutes
Moon Phase for October 11th at Midnight
2.3 Days Days After Last Quarter Moon
What's in the Night Sky?
"What better way to start out the day than to enjoy the waning crescent moon and dazzling planet Venus before sunrise? You might also spot Regulus, the brightest star in the constellation Leo the Lion, up before the sun. Although Regulus is a 1st-magnitude star, or one of the brightest stars in our sky, Leo’s brightest star pales next to Venus. Brilliant Venus outshines Regulus by well over 100 times. Watch these three objects – the moon, dazzling Venus and bright Regulus – adoring the morning dawn on October 12, 13, 14 and 15, 2020. Simply get up before daybreak, and look eastward. The moon and Venus are nearby objects in our own solar system, shining by reflecting the light of our local star, the sun. Meanwhile, Regulus shines with its own light and is, in truth, a vastly more powerful object than either the moon or Venus, shining across some 79 light-years of space. It just doesn’t look as bright in our sky because it’s so far away. This mighty star is considerably larger and hotter than our sun. If it were located at the sun’s distance from us, Regulus would appear some 150 times brighter than our sun in the visible spectrum. The moon will pass 4 degrees north of Venus on October 13 at 23:57 Universal Time (UTC). We won’t see the moon and Venus at this instant from the United States, because they’ll be either beneath the horizon or lost in a daytime sky. For us, the moon will be to the west of Venus on the morning of October 13 and to the east of Venus on the morning of October 14."
(Image Credit: EarthSky.org)
National Forecast Map For Sunday
The National Forecast Map for Sunday shows lingering showers and storm in the Southeast from the remnants of Delta. Meanwhile, strong to severe storms will be possible in the Upper Mississippi Valley late Sunday. Much needed precipitation continues in the Northwestern US with areas of snow possible in the high elevations. Note that there is a risk of strong to severe storms across parts of the Carolinas and also in the Upper Midwest.
National Weather Outlook
Remnants of Delta will lift northeast through the end of the weekend and into early next week with widespread showers and storms. Some of the rain could be heavy with isolated flood concerns. Meanwhile a strong front will push through the Upper Midwest PM Sunday with a risk of strong to severe storms there. Areas of rain and snow will continue in the Northwest on Sunday and linger into early next week.
Delta Rains Move Northeast; Heavy Precipitation in the Northwest.
Here's the 7-day preciptation outlook across the nation, which shows areas of heavy rains from Delta moving into the Northeast through early next week. Folks in the Upper Midwest will be getting a round of fairly decent rains PM Sunday into Monday. There also appears to be heavy precipitation potential in the Northwest. However, the Southwest will remain mostly dry.
National Snowfall Potential
It's getting to be about that time of the year... Here's the snowfall potential through Wednesday Night, which shows areas of potentially heavier snow in the Rockies from NW Colorado to Monanta and in the Northern Cascades in Washington.
Ongoing Wildfires in the Western US
Take a look at how many ongoing wildfires there are across the Western US. Of course it has been extremely hot and dry as of late, but recent thunderstorms have resulted in hundreds of new fires since last week. Cal Fire reports that:
Since the beginning of the year, there have been over 8,400 wildfires that have burned well over 4 million acres in California. To date, the total number of fatalities statewide is 31 and more than 9,200 structures have been destroyed.
Hurricane Delta made landfall near Creole, Louisiana at 6PM on Friday, October 9th as a Category 2 storm with 100mph winds. This became a record, 10 named tropical systems to make a U.S. landfall this season! The previous record was 9 set in 1916. This was also the first named storm in the Greek Alphabet to make a U.S. landfall! Interestingly, the only other year to use the Greek Alphabe to name storms was back in 2005 and that year, the last storm to develop was Zeta. According to NOAA's NHC, there is another wave of energy in the central Atlantic that currently has a low probability of tropical formation over the next 5 days. Stay tuned...
A View of Delta From Saturday Morning
This view of Delta early Saturday morning, wasn't quite as impressive as it was earlier this week. With that said, it was still producing tropical storm force winds and dumping heavy rains. Unfortunately, Hurricane Delta made landfall in nearly the same spot that Hurricane Laura did 6 weeks ago.
Secondary Spike in Mid October?
While the peak of the Atlantic Hurricane Season is behind us (September 10th), there is usually a secondary spikes that happens around mid October. Things are rather quiet in the Atlantic now, but don't let your guard down, things could still get interesting. Stay tuned...
No More Regular Alphabet Names
It has been an active season so far as we've used up all 21 names that NOAA's NHC set for the year. Interestingly, Tropical Storm Arthur developed back in mid May, more than 4 months ago! Since then, we've had a total of 9 huricanes!
We're Into the Greek Alphabet - First Time Since 2005
Not only did we use up all 21 names in the list above, but we've entered the Greek Alphabet, which is only the 2nd time in recorded history that we've done that and the first time since 2005. Delta became the 25th named storm and the 9th hurricane of the 2020 Atlantic Hurricane Season.