Some Rain, Low Streams in Illinois

7-Day Rainfall (NWS)

Here are the 7-day totals for the central US, capturing the rainfall over the weekend. As forecasted, the heaviest rains were in Missouri and along the IL/MO border. Shades of green represent 0.5 to 2.0 inches.Most of IA, MI, IN, and OH received moderate amounts of rain from this system. However, large parts of Illinois received less than 0.5 inches (shaded in blue).

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Streamflows (USGS)

A pattern of below-normal stream flows has developed across central and southern Illinois (map below). Stations with flows below the 10th percentile, meaning that the rate is in the bottom 10 percent of all flows observed for this time of year, are in red. Stations with flows between 10 and 24th percentiles are in orange. These low numbers reflect the warm, dry winter and early spring. While the stream flows are low for this time of year, they are still higher compared to the really low flows we normally see in late summer.

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Forecast for next 7 days (NWS)

The NWS precipitation forecast for the next 7 days indicates that there is the potential for widespread rains across the south and lower Midwest. Rainfall amounts in central and southern Illinois are in the neighborhood of 1.5 to 3 inches, and between 0.75 and 1.5 inches in northern Illinois.

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Outlook for Spring – Warm

Notwithstanding this week, the outlook for this spring is warm. The Climate Prediction Center released their outlook on Thursday for April and beyond. Right now both El Niño and La Niña are out of the picture. However, there is much uncertainty for future conditions in the Pacific. Some models suggest that El Niño may return by late summer. As we move forward, we should get a clearer idea about El Niño.

April

Illinois and much of the Midwest have an increased chance of above normal temperatures. Illinois has equal chances “EC” of above, below, or near-normal precipitation. I call EC a neutral forecast.

April – June

Like the outlook for April, the one for April through June shows Illinois and the Midwest with an increased chance of above-normal temperatures and nothing on precipitation.

June – August

The heart of summer shows Illinois with an increased chance of above-normal temperatures. But more interesting is that they have introduced a region of below-normal precipitation in the southern half of Illinois. The combination of warmer and drier than normal conditions during that time of year could lead to drought.

September – November

More of the same – a greater chance of above-normal temperatures across Illinois and the US. Nothing is said about precipitation.

What! More Snow in March Than February?

Some places in Illinois have been snowier in March than April. About the only noteworthy snowfall of February occurred in a band from Peoria to Hoopeston. So far in March, snow has pushed farther south, all the way to the Ohio River. At the same time, areas in northern Illinois have received substantially more snow in March than February. For example, Chicago O’Hare reported only a trace of snow in February and 7.8 inches of snow in March through this morning.

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Is the Drought Monitor Crying Wolf in Illinois?

The latest US Drought Monitor map shows moderate drought in western and southwestern Illinois, based primarily on below-normal precipitation over the past three months. Are we in moderate drought? I  think it’s premature to declare drought in Illinois.

While it has been dry this winter, the demand on water supplies and soil moisture are very low in winter. In an average winter, we have more than enough water to satisfy demand – in many cases too much water. As a result of low water demand, the impacts of below-normal precipitation on water supplies, navigation, and agriculture are harder to find in winter.

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Fifth Warmest Winter in Illinois

This winter was the 5th warmest winter on record for Illinois. The statewide average temperature was 34.0 degrees, 4.9 degrees above the 1981-2010 normal. It actually beat out last winter, which was a surprise. Last winter was expected to be mild because of El Niño. Here are the top 10 mildest winters in Illinois history. Temperatures are in degrees F. Three of those top ten winters have occurred since 2000 and seven since 1980.

Rank Winter Temperature Departure
1 1931-32 36.4 7.3
2 2001-02 34.7 5.6
3 1997-98 34.6 5.5
4 2011-12 34.5 5.4
5 2016-17 34 4.9
6 1991-92 33.9 4.8
7 2015-16 33.9 4.8
8 1982-83 33.6 4.5
9 1920-21 32.9 3.8
10 1918-19 32.8 3.7

Here are the winter temperatures in Illinois since 1895. There is a 1.7-degree warming per century. That doesn’t sound very spectacular. But what’s really happening is that we are getting more mild winters and fewer severe winters (highlighted). But what about 2013-14? That was the exception that proved the rule – a cold winter by modern standards, but not unusual by 1970s or early 20th century standards. Continue reading

Warmest February on Record for Illinois

All those days with 60- and 70-degree weather paid off – this February was the warmest February on record for Illinois. The statewide average temperature for February was 41.0 degrees, 10.1 degrees above normal. It beat the old record of 40.0 degrees set back in 1998. [Updated March 8 to reflect NCEI report]

It was dry too. The statewide average precipitation for February was 0.7 inches, 1.36 inches below normal and the 9th driest February on record.

Statewide records go back to 1895.

Precipitation

High-resolution radar/rain gauge product showing amounts and departure from normal. Precipitation was near normal in the northern half of the state but below normal in the southern half. For many places, February is the driest month of the year. We don’t notice it because the water demand is low and most of the precipitation falls as snow so it feels like a bigger deal than it really is. Continue reading

Warm February Raises Issues

img_1749A batch of crocus on the south side of our office building is a reminder of the impacts of warm weather in February. Both January and February have been mild. But on top of that has been a record-setting streak of 60s and 70s in the past week. As a result, many early season perennials such as crocus are coming out a little early. In the past, such warm weather has made any early vegetation vulnerable to the inevitable freeze later on. In 2007 and 2012, a similar scenario played out with damage to corn, winter wheat, alfalfa, and fruit crops across Illinois. The 2007 event was well documented in this report.

In Illinois alone, 257 daily record high temperatures at sites across the state were either tied or broken. Our experience in Champaign-Urbana is typical with five daily records tied or broken on days with highs in the upper 60s and low 70s. The warmest temperature reported for February in Illinois is 79 degrees on the 21st in Perry IL, near Quincy. A nearby site in Pittsfield reported 78 on the same day.

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