The Midwestern Regional Climate Center has extensive databases on daily temperature, precipitation, and snowfall across Illinois and the Midwest. This used to be a subscription-based system. In fact, one of my original jobs at the Illinois State Water Survey was working on the original version of this system, then called MICIS. In 2013 they revamped the system and made it free to everyone. All that’s required is a quick registration. The URL is http://mrcc.isws.illinois.edu/CLIMATE/ Check it out!
I use it for almost all my data, mapping, and plotting needs at work. For example, here is a plot for Chicago of daily temperature and precipitation so far in June of this year. This is a screen shot, the live version allows the pop-up window to move with the cursor.
June rainfall has been well above average for much of Illinois. Rainfall amounts in the 3 to 8 inch range were common in the last 14 days (yellow to red in the map below). The relatively driest part of the state was the northwest corner where amounts were less than 2 inches. Heavy rainfall amounts were reported in Missouri, southern Iowa, and Indiana as well.
The NWS precipitation forecast for the next 7 days (map below) shows more opportunities for rain, especially in northern Illinois. The 6-10 day and 8-14 day forecast show an increased chance of wetter-than-average conditions for Illinois and the eastern Cornbelt.
At the beginning of June we had some concerns for western Illinois, especially with low river and stream flows and short to very short subsoil moisture (below 6 inches). The recent rains have improved the situation to some degree. For example, the La Moine River at Collmar IL USGS stream gauge increased from 30 cubic feet per second on June 1 to 3,000 cubic feet per second on June 8, a one-hundred fold increase in flow (figure below).
The last USDA report from June 9 showed widespread improvements in topsoil moisture. In fact, 12 percent of the state reported excess topsoil moisture. I suspect that percentage would be even higher now. However, subsoil moisture in western Illinois improved only slightly, suggesting that much of the rain ran off into the streams and rivers instead of recharging the deeper layers of the soil.
Based on preliminary data, the statewide average temperature for May in Illinois was 63.9 degrees. That is 1.2 degrees above average and the first month to be above average in Illinois since October 2013.
The statewide average precipitation for May in Illinois was 4.26 inches, just 0.34 inches below average. Below is a map of precipitation throughout the state. This is a radar-based product that is adjusted with rain gauges, resulting in higher resolution than a rain gauge network and more accuracy than a radar-only precipitation measurement. Sometimes hail can mislead the radar into calculating higher rainfall rates. That may have been the case in southern Champaign County, for example.
Some of the heaviest rainfall totals from the CoCoRaHS network for May occurred in Cook County, including Burnham-Hegewisch (IL-CK-82) with 7.64 inches and Homewood (IL-CK-64) with 7.58 inches.
The area of concern for May was the large section of blue across western and central Illinois, representing rainfall totals of only 1 to 3 inches. There are some smaller patches of blue in southern Illinois and far northwestern Illinois as well. One of the drier locations in west-central Illinois was Roseville (IL-WR-2) with only 1.32 inches with all 31 days reported. The US Drought Monitor list parts of western Illinois as “abnormally dry”.
Plots of Temperature and Precipitation
Here are the time series plots for temperature and precipitation departures for each month of 2013 and 2014. In the first plot, one can clearly see the string of very cold months from November 2013 to April 2014. On the second plot, the dryness of late last summer shows up. While March of this year was dry, it was counterbalanced by a wetter than average April.
According to preliminary records, the first half of May was both warmer and wetter than average for many locations in Illinois. The statewide average temperature was 61.2 degrees, about 1.4 degrees above average. Meanwhile, this morning there are reports of snow falling in northern Illinois. Talk about weather extremes. This was after last weekend when we saw widespread reports of highs in the upper 80s and low 90s.
The statewide average precipitation was 2.43 inches, 18 percent above average. Here is a screenshot of the last 14 days showing the widespread and heavy rainfall in much of the northeast, east-central, and southern parts of Illinois with many sites reporting between 3 to 6 inches of rain. Parts of western and central Illinois have not been as wet with amounts in the range of 1 to 3 inches of rain.
Snow in May? Read more on the Chicago NWS page. It looks like Rockford set a new record for the latest report of snowfall in the season. The Chicago record still stands at June 2, 1910.
Map courtesy of the Chicago NWS office.
The Climate Prediction Center released their latest forecasts today (May 15) for June and this summer with cooler and wetter than average conditions expected in parts of Illinois.
The temperature forecast for June (Figure 1) in Illinois includes an area to the north of Interstate 74 with an increased chance of being cooler than average. This is part of a larger area of cooler conditions that runs across the northern states from the Rockies to the Appalachians. The rest of Illinois is labeled EC for equal chances of above, below, and near-average conditions – a neutral forecast.
Figure 1. June Temperature. Click to enlarge.
The precipitation forecast for June (Figure 2) in Illinois includes an area south of Interstate 74 with an increased chance of above average precipitation. BTW, while I used Interstate 74 as the dividing line, the forecast obviously is not that precise in terms of geography.
Figure 2. June Precipitation. Click to enlarge.
The temperature forecast for June-August (traditional summer) includes northern Illinois in an area with an increased chance of below-average temperatures along with states to the north. The rest of Illinois is labeled EC for equal chances (Figure 3).
Figure 3. Click to enlarge.
The precipitation forecast for June-August (traditional summer) has EC across Illinois and most of the Midwest (Figure 4).
Figure 4. Click to enlarge.
If the temperature pattern for June and June-August seems familiar, here is what we have experienced in the last 30-days for Illinois and the Midwest (Figure 5). Notice the much-colder-than average temperatures across the upper Midwest (4 to 8 degrees below average). Also central Illinois has been the dividing line between the colder-than-average conditions to the north and the slightly warmer-than-average conditions to the south.
Figure 5. Click to enlarge.
The NOAA Climate Prediction Center has released a new El Niño watch stating,
Chance of El Niño increases during the remainder of the year, exceeding 65% during summer.
At this point it is not clear how strong this El Niño will be. However, it has the potential to be very strong. The two major El Niño events in my career were the 1982-83 and 1997-98 event. Looking at the June-August period at the start of those two events, there was a widespread pattern of cooler than average (1981-2010) conditions across the Midwest. On the other hand, there was not a consistent pattern of precipitation. Average to above-average precipitation fell in Illinois in the summer of 1982 while average to below-average precipitation fell in 1997, depending on where you were. It was notably drier in western Illinois in the summer of 1997.
The temperature pattern shifted in September and October, with warmer than average conditions in the western Corn Belt. This was especially true in 1997. Illinois was split with the northwest being warmer and the southeast being colder than average for September/October. This fall was notably dry across the northern half of Illinois in 1982 and near-average in 1997.
Overall, the last two major El Niño events produced widespread cooler summer temperatures but were somewhat inconsistent in terms of fall temperatures as well as summer and fall precipitation. Of course, our sample size is small and as the stock brokers are supposed to say, “past performance does not guarantee future results”.
BTW, over at climate.gov there is a new blog about El Niño-Southern Oscillation (ENSO) that describes the situation on a regular basis. ENSO is the general term for El Niño (warm phase), La Niña (cold phase), and the neutral phase of conditions in the Pacific Ocean along the equator. In fact, they have an excellent short tutorial on the three phases here. Here is an excellent illustration of the La Niña and El Niño pattern in the Pacific Ocean from NOAA. One can clearly see the blue colder than average waters across the equator during La Niña (top panel) and the red warmer than average waters during El Niño (lower panel).
Observed Precipitation Changes in the US. The colors on the map show annual total precipitation changes for 1991-2012 compared to the 1901-1960 average, and show wetter conditions in most areas. The bars on the graphs show average precipitation differences by decade for 1901-2012 (relative to the 1901-1960 average) for each region. The far right bar in each graph is for 2001-2012. (Figure source: adapted from Peterson et al. 20131). Click to enlarge.
The third U.S. National Climate Assessment was released today, including state-specific fact sheets like this one for Illinois. I’ll post some Illinois specific comments in the near future.
The assessments are mandated by law with the intent of providing the latest report of climate change and it’s impacts on the United States.
Here are the key findings for the Midwest (the Midwest report is located here):
- In the next few decades, longer growing seasons and rising carbon dioxide levels will increase yields of some crops, though those benefits will be progressively offset by extreme weather events. Though adaptation options can reduce some of the detrimental effects, in the long term, the combined stresses associated with climate change are expected to decrease agricultural productivity.
- The composition of the region’s forests is expected to change as rising temperatures drive habitats for many tree species northward. The role of the region’s forests as a net absorber of carbon is at risk from disruptions to forest ecosystems, in part due to climate change.
- Increased heat wave intensity and frequency, increased humidity, degraded air quality, and reduced water quality will increase public health risks.
- The Midwest has a highly energy-intensive economy with per capita emissions of greenhouse gases more than 20% higher than the national average. The region also has a large and increasingly utilized potential to reduce emissions that cause climate change.
- Extreme rainfall events and flooding have increased during the last century, and these trends are expected to continue, causing erosion, declining water quality, and negative impacts on transportation, agriculture, human health, and infrastructure.
- Climate change will exacerbate a range of risks to the Great Lakes, including changes in the range and distribution of certain fish species, increased invasive species and harmful blooms of algae, and declining beach health. Ice cover declines will lengthen the commercial navigation season [this winter was the exception to the rule - Jim].