Category: Climate Monitoring

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Fall Color

One of the best things about this time of year is the fall color. I suppose I’m hopelessly Midwestern because I even enjoy the change in color of the corn fields.
The question I often get is “How will the weather affect this year’s color?” It is hard to answer. Here are some comments I made in a press release a few years ago about the recipe for good fall color.

“Trees and shrubs need to go into the fall without a lot of stress from disease or severe drought. Chilly, not frigid nights and cool, sunny days enhance the changing leaf colors. Detrimental conditions include extended periods of rain or cloudiness that mute colors, high winds that blow leaves off trees, and hard freezes that stop color changes entirely… October and early November in Illinois should put on quite a show. Take some time to go out and enjoy it,” concludes Angel.

Check out the official site of the Illinois Office of Tourism for fall activities. The University of Illinois Extension Service site called “The Miracle of Fall” is an excellent source of information as well. [Update] NOAA has a featured story on fall color that includes a link to a more technical discussion of fall leaf color.
 

Miracle of Fall
University of Illinois Extension site on "The Miracle of Fall".

 

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Tropical Storm Hermine Reaches Illinois

The remains of Tropical Storm Hermine have reached Illinois this morning. Rainfall amounts of 1 to 3 inches are possible and flash flood warnings have been issued. Check the National Weather Service as this event unfolds.
While we don’t often use the words “tropical” and “Illinois” in the same sentence, the remains of tropical storms and hurricanes have reached us before. Most of these systems came on shore in Texas and Louisiana and weakened considerably as they moved northward. Usually, the severe weather is gone by the time they reach Illinois but they can produce large amounts of rain than can lead to flooding.
The passage of four tropical systems alleviated drought impacts, particularly in southern and central Illinois during the 2005 growing season. The four systems were Tropical Storm Arlene, and Hurricanes Dennis, Katrina, and Rita. An article in the Illinois State Academy of Science by me described that situation in more detail.
More recently, in September 2008 the remains of Hurricanes Ike and Gustav produced heavy rains and flooding in Illinois. More on that particular situation can be found on my website.

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Summer – One of the Warmest and Wettest on Record

Summer

This summer was one of the warmest and wettest in Illinois history, based on preliminary data. The average statewide temperature for this summer (June-August) was 76.4 degrees, 2.7 degrees above normal and the seventh warmest summer on record. The average statewide rainfall was 16.7 inches, 5.2 inches above normal and the sixth wettest summer on record. Statewide records for Illinois extend back to 1895.

August

The average statewide temperature for August was 76.8 degrees, 3.2 degrees above normal. That puts it at the 13th warmest August on record.  August was on track to being even warmer but a late-month cool spell knocked it down a few notches in the ranking. August rainfall has been close to normal with a statewide average of 3.4 inches, just 0.3 inches below normal.
[This is an update of a post earlier in August, now removed to avoid confusion]

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Dry Weather in Southern and East-Central Illinois

After a wet start to the 2010 growing season, two areas of dryness have persisted in the last 60 days (see map below). The first area is far southern Illinois, where dry conditions extend back to June. The second, more recent area is in east-central Illinois. The hardest hit area appears to include parts of the following counties: McLean, Ford, Livingston, Iroquois, and Kankakee. Rainfall in that area has been between 25 and 75 percent of normal. Meanwhile, temperatures during that same period have run about 2.5 degrees above normal.
As expected, topsoil moisture in east-central Illinois has declined rapidly in recent weeks. According to the latest USDA NASS report, the “East” Crop Reporting District (CRD) in the heart of the dry area is showing that 35% of the fields sampled had “very short” and 48% of the fields had “short” topsoil moisture.
In southern Illinois, the percentages of fields with “very short” to “short” topsoil moisture are as follows:

  • East Southeast CRD: 16 % “very short” and 43% “short”
  • Southwest CRD: 17% “very short” and 65% “short”
  • Southeast CRD: 66% “very short” and 12% “short”
60-day rainfall departure
The 60-day (July 2 - August 30) rainfall departure from normal for the Midwest.