Wet April and 2nd Warmest January-April on Record for Illinois

Precipitation: The statewide average precipitation for April in Illinois was 7.01 inches, 3.23 inches above normal and the 2nd wettest April on record. Here are the top five wettest Aprils. Notice a pattern? Three out of the five have been since 2011.

  1. April 2011 – 7.62 inches
  2. April 2017 – 7.01 inches
  3. April 1957 – 6.99 inches
  4. April 2013 – 6.93 inches
  5. April 1927 – 6.87 inches

The largest monthly total for April in Illinois was Carbondale with 14.41 inches. Several other sites in southern Illinois had similar amounts including Bush (Williamson County) with 13.63 inches, West Frankfort (Franklin County) with 13.35 inches, Kaskaskia (Randolph County) with 13.34 inches, and Murphysboro (Jackson County) with 13.02 inches.

Temperature: The statewide average temperature for April was 56.4 degrees, 3.8 degrees above average and the 11th warmest April on record. The warmest reading for April was 89 degrees at Kaskaskia on April 20.  The coldest reading for the month was 19 degrees at Morrison on April 10.

Statewide records of temperature and precipitation go back to 1895.

Graphs

Here are the temperature departures for 2017. As you can see, every month in 2017 has been well above normal. So far this January-April is the 2nd warmest such period on record with a statewide average temperature of 43.2 degrees, 5.4 degrees above normal. Only 2012 was warmer at 44.5 degrees, 6.7 degrees above normal. [corrected from an earlier version]

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Heavy Rains Over the Last 7 Days in Illinois

As predicted, heavy rains have fallen across much of Illinois in the last 7 days. The first round came on Wednesday and Thursday of last week, followed by another round starting Friday night and tapering off Sunday night.

The largest total for the last 7 days, as of Monday morning, was 12.03 inches at Carbondale. Five other stations reported amounts in the 8-inch range: Kaskaskia with 8.96 inches, Steeleville with 8.66 inches, Murphysboro with 8.60 inches, Chester with 8.23 inches, and Flora with 8.15 inches. A more extensive list is at the bottom of this post.

Here is the radar/rain gage product for the last 7 days. As confirmed by the rainfall reports, the heaviest rains fell in southern Illinois. The area around Carbondale received between 10 and 15 inches. Areas in the shades of red were between 5 and 10 inches. Meanwhile, the northern half of Illinois got off a little easier with amounts of 2 to 4 inches.

Capture

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Widespread, heavy rains possible over next week in Illinois

As of April 25, the statewide average precipitation for Illinois is 2.8 inches, which is 94% of normal. However, we have several opportunities for widespread rains this week and into the weekend, according to the NWS precipitation forecast.

The first round of rain on Wednesday and Thursday has potential rainfall amounts of 1 to 2 inches across most of Illinois, along with the chance for severe weather. Continue reading

National Climate Assessment for Illinois

Earlier this year the National Climate Assessment for Illinois was released, tracking the historical changes in temperatures and precipitation in Illinois. You can find the full report for Illinois and other states at the State Climate Summaries website.

Here is Key Message #1

Average annual temperature has increased by about 1°F since the beginning of the 20th century. There has been seasonal variation in this warming, with average spring temperature increasing by about 2°F and average summer
temperature increasing very little. Under a higher emissions pathway, historically unprecedented warming is projected by the end of the 21st century.

Key Message #2

Precipitation in spring and summer has generally been above average over the past two decades, affecting agriculture in both positive (adequate soil moisture) and negative (delays in spring planting) ways. Precipitation in winter and spring is projected to increase, which poses a continuing risk of spring planting delays.

Key Message #3

Severe flooding and drought have occurred periodically in recent years. Future increases in extreme precipitation events and in evaporation rates may increase the intensity of both floods and droughts.

You may notice that two out of the three messages relate to increases in precipitation and especially heavy rainfall events. The graphic I found most compelling was this one for the increasing number of 2-inch rain events with time. The caption explains how this graph was created. The increased frequency in 2-inch rain events seen since the early 1980s lines up very well with my experience and research over the years in Illinois.

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Figure 5: The observed number of days with extreme precipitation events (annual number of days with precipitation greater than 2 inches) for 1900–2014, averaged over 5-year periods; these values are averages from 43 available long-term reporting stations. A typical station experiences 1–2 such events each year. The number of extreme precipitation events has been above average since the 1990s. During the most recent 5-year period (2010–2014), Illinois experienced a record high number of events when stations averaged more than 2 events annually. The dark horizontal line is the long-term average (1900–2014) of 1.62 days per year. Source: CICS-NC and NOAA NCEI.

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Above-Average Temperatures Expected to Continue through Fall

The NWS released their latest forecasts for May and beyond. Currently, the Pacific Ocean is in the neutral phase between La Niña and El Niño. There is much debate on if and when El Niño should return. It could happen in late summer.  Meanwhile, the theme running through the outlooks is the increased risk of above-average temperatures through the fall. Illinois has been running warmer than average in the last few years. In 2016, 10 out of 12 months were above-average. So far, every month in 2017 has been above-average.

  • January 2017: 5.7 degrees above average
  • February 2017: 10.1 degrees above average
  • March 2017: 1.9 degrees above average
  • April 1-19, 2017: 6.5 degrees above average

May: eastern portions of Illinois have a slightly increased chance of being warmer than average. I am going out a little farther on the limb and say that all of Illinois has an increased chance of being warmer than average, based on recent trends and the climate models. Meanwhile, most of Illinois and the Great Lakes are expected to have an increased chance of below-average precipitation. Click to enlarge maps. Continue reading

April Showers Bring May Flowers?

The first part of April has been warmer and wetter than average across much of Illinois and the Midwest. As these maps show, there is a wide band of 1 to 3 inches of rain stretching from Kansas, through Missouri, Indiana, Michigan, and Ohio (click to enlarge) in April. These rains have helped ease concerns of any developing drought after the dry winter. In fact, the concerns have reversed and center around delays in field work from wet conditions. Continue reading

March in Illinois – Lots of Snow and Rain

March Temperatures: The statewide average temperature for March was 42.3 degrees, 1 degree above normal. Temperatures swung from periods several degrees above normal and several degrees below normal with little time in-between. Several sites reported temperatures reaching into the 80s. The warmest daily report was Belleville with 86 degrees on March 21. Chicago Midway reported a high of 82 degrees on March 24. Meanwhile, the coldest temperatures of the month were experienced in the northwest quarter of the state, including Altona and Illinois City with a low of 6 degrees on March 25.

March Precipitation: The statewide precipitation was 3.62 inches, 0.66 inches above normal. The highest monthly total precipitation was Lockport with 7.22 inches. Precipitation was greatest in a wide band from Quincy to Chicago with amounts between 3 to 6 inches, which is 1 to 3 inches above normal. The driest area was in southeastern Illinois with only 1 to 2 inches, which is 1 to 2 inches below normal. Click on the maps below for a closer view. Continue reading